Intraperitoneal Injection Of Dexamethasone Research Articles

Гистологические и иммуногистохимические изменения префронтальной коры головного мозга мышей под действием дексаметазона

Introduction. The effects of the synthetic glucocorticoid dexamethasone on target organs are mediated by the interaction with the glucocorticoid receptor, but the effects of the drug on the intact brain have been poorly studied. We aimed to look at a one-time and repeated exposure to a two-dose dexamethasone on the expression of the glucocorticoid receptor and cellular changes in the prefrontal cortex over time. Materials and methods. Male C57Bl/6 mice aged 7–8 weeks received a one-time or multiple intraperitoneal injections of dexamethasone in doses of 1.0 or 2.5 mg/kg. Structural changes in the prefrontal cortex were analyzed on paraffin sections stained by hematoxylin and eosin 90 days after the injection. The expression of the glucocorticoid receptor was studied with immunohistochemistry using monoclonal antibodies and quantitative analysis. Results. A histological study of the prefrontal cortex exposed to a two-dose dexamethasone revealed the absence of an obvious dose dependence and the reversibility of dystrophic and hydropic changes. The most pronounced changes were revealed with a one-time administration of the drug (on day 7) and repeated administration (on day 15) while normal tissue architecture returned to that of the control groups. The expression level of the glucocorticoid receptor after a one-time dexamethasone injection at a dose of 2.5 mg/kg showed a significant growth (р<0.05) on days 3 and 10 compared to that of the control group, while after multiple dexamethasone injections, the GR expression decreased on day 15, but by day 30 it returned to its initial level. Conclusion. Stereotypical dystrophic and hydropic changes in the prefrontal cortex during exposure to two different regimens and dexamethasone doses developed on days 7 and 15. We revealed an opposite effect of 2.5 mg/kg dexamethasone administration regimens on the expression of the glucocorticoid receptor in the prefrontal cortex of mice relative to the control group: at a one-time administration the expression increased by 8.1% on day 10 and at multiple administration the expression grew by 9.9% on day 15. Keywords: dexamethasone, glucocorticoids, brain, prefrontal cortex, glucocorticoid receptor, immunohistochemistry

Insulin-sensitizing and antioxidant effects of <i>Ethulia</i> <i>conyzoïdes</i> aqueous extract in dexamethasone-induced insulin resistant rats

Rising the prevalence of type 2 diabetes mellitus in sub-saharian Africa has necessitated surveys of antidiabetic medicinal plants. Ethulia conyzoïdes is a plant widely used in traditional medicine to treat diabetes. However, the different mechanisms by which it exerts its antidiabetic effects remain unknown. Thus, this study aimed to investigate the effect of Ethulia conyzoïdes aqueoux extract on dexamethasone-induced insulin resistance in Wistar rats. Insulin resistance was induced by intraperitoneal injection of dexamethasone (1mg/kg) for 8 days and the animals received simultaneously, orally, distilled water (insulin resistant control group) and, metformin (100 mg/kg) or Ethulia conyzoïdes aqueoux extract at doses of 133 and 266 mg/kg. Normal control rats received NaCl 0.9% (intraperitoneal by injection) and distilled water orally. Insulin sensitivity, total cholesterol, triglycerides, transaminases activity and redox status were evaluated. Results showed a significant reduction of insulin tolerance (p<0.001), a drastic increased of transaminase activity (p<0.05), hyperlipidemia, and a great potentiation of liver antioxidant enzymes (GSH, SOD and catalase) in insulin resistant control group. Ethulia conyzoïdes aqueoux extract markedly improved insulin sensitivity and reversed all the modified parameters. This study demonstrated the efficacy of Ethulia conyzoïdes aqueoux extract to improve insulin sensitivity and manage biochemical disorders induced by insulin resistance. Short term administration of dexamethasone appears to stimulate the first line antioxidant defense in order to counteract oxidative stress, meaning that Ethulia conyzoïdes aqueoux extract inhibited free radicals production.

Study on the therapeutic effect of glucocorticoids on acute kidney injury in rats exposed to diquat

AimsTo preliminarily explore, whether glucocorticoids have a therapeutic effect on diquat-induced acute kidney injury in rats. Method150 Wistar rats were randomly divided into six groups: exposure model group (DQ group), dexamethasone control group (GC group), blank control group (Ctrl group), dexamethasone 2.1 mg/kg dose group (DQ+L-GC group), dexamethasone 4.2 mg/kg dose group (DQ+M-GC group), and dexamethasone 8.4 mg/kg dose group (DQ+H-GC group), with 25 rats in each group. Each group was further divided into five subgroups, 24 h, 3 d, 7 d, 14 d, and 21 d after exposure, according to the feeding time and the course of treatment, with five animals in each subgroup. The rats in DQ, DQ+L-GC, DQ+M-GC, and DQ+H-GC groups were administered 115.5 mg/kg diquat by gavage, respectively. Moreover, 30 min after gavage, rats in DQ+L-GC group, DQ+M-GC group, DQ+H-GC group and GC group were intragastric administered dexamethasone 2.1 mg/kg, 4.2 mg/kg, 8.4 mg/kg and 8.4 mg/kg, respectively. After 7 days, the intraperitoneal injection of dexamethasone was changed to 6.3 mg/kg prednisone by intragastric administration. Subsequently, 7 days later, it was changed to 3.15 mg/kg prednisone by intragastric administration until the end of the experiment on 21 days. After the start of the experiment, changes in the conditions of the rats in each group were observed at a fixed time every day, changes in the body weight of the rats were monitored at the same time, and the death of the rats was recorded at 24 h, 3 d, 7 d, 14 d, and 21 d after exposure. The rats were sacrificed by an intraperitoneal injection of 100 mg/kg sodium pentobarbital overdose. Blood was collected by puncture of the inferior vena cava, used to determine Cr and BUN. The upper segment of the left kidney was collected for histopathological examination. Elisa was used to detect neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) in the lower segment of left kidney. TLR4, Myd88, and NF-κB were detected in the right kidney. Results(1) After exposure, most rats in DQ group, DQ+L-GC group, DQ+M-GC group and DQ+H-GC group showed shortness of breath, oliguria, diarrhea, yellow hair and other symptoms. No symptoms and related signs were observed in Ctrl group and GC group.(2) The weight of rats in the Ctrl group and the GC group increased slowly during the test. the body weight of the rats in the DQ, DQ+L-GC, DQ+M-GC, and DQ+H-GC groups continued to decrease after self-infection. Body weight dropped to the lowest point at approximately 7 d, and gradually increased from 7 d to 21 d.(3) A small amount of capillary congestion in the medulla was observed after 7 days in the GC group. The DQ group showed tubular atrophy, edema of the epithelial cells, and over time, the tubules were seen dilated and became irregular in shape; large amount of capillary congestion was also observed in the renal cortex and medulla. The renal injury in the DQ+L-GC group was less than that in the DQ group. DQ+H-GC group had no obvious injury before 7 d, but more renal tubules were seen in the DQ+H-GC group from 7 d to 14 d.(4) Compared with the DQ group, there was no difference before 14 d, and at 14 d-21 d, DQ+L-GC group, DQ+M-GC group, DQ+H-GC group all had different degrees of decline. NGAL content: Compared with the DQ group, the content of NGAL and KIM-1 in kidney tissue of the DQ+L-GC, DQ+M-GC, and DQ+H-GC groups decreased compared with the DQ group at each time node.(5) Compared with the Ctrl group, the expression of TNF-α, TLR4, MyD88, NF-κB in the DQ, DQ+L-GC, DQ+M-GC, and DQ+H-GC groups at each time node increased in the renal tissue. The content of TNF-α, TLR4, MyD88, NF-κB in kidney tissue of the DQ+L-GC, DQ+M-GC, and DQ+H-GC groups at each time node was lower than that in the DQ group. Conclusion(1) Diquat can cause kidney damage in rats, mainly manifested as renal tubular atrophy, epithelial cell edema, capillary congestion and dilation, and the renal function damage indicators have been improved to varying degrees.(2) Glucocorticoids have therapeutic effects on acute kidney injury in rats exposed to diquat. During the treatment, the efficacy of glucocorticoids did not increase with increasing doses after reaching a dose of 4.2 mg/kg.(3) TLR4 receptor-mediated TLR4/Myd88/NF-κB signaling pathway is involved in the inflammatory response of acute kidney injury in diquat poisoning rats. Glucocorticoids can inhibit the inflammatory response, thereby affecting the expression of TLR4/Myd88/NF-κB signaling pathway-related proteins.

Melatonin alleviates ovarian function damage and oxidative stress induced by dexamethasone in the laying hens through FOXO1 signaling pathway

Oxidative stress can trigger follicular atresia, and decrease follicles quantity in each development stage, thereby alleviating reproductive activity. The induction of oxidative stress in chickens through intraperitoneal injection of dexamethasone is a reliable and stable method. Melatonin has been shown to mitigate oxidative stress in this model, but the underlying mechanism remains unclear. Therefore, this study aimed to investigate whether melatonin can recover aberrant antioxidant status induced by dexamethasone and the specific mechanism behind melatonin-dependent protection. A total of 150 healthy 40-wk-old Dawu Jinfeng laying hens with similar body weights and laying rates were randomly divided into three groups, with five replicates per group and 10 hens per replicate. The hens in the control group (NS) received intraperitoneal injections of normal saline for 30 d, the dexamethasone group (Dex+NS) received 20 mg/kg dose of dexamethasone for the first 15 d, followed by the 15 d of normal saline treatment. While in the melatonin group (Dex+Mel), dexamethasone (20 mg/kg dose) was injected intraperitoneally in the first 15 d, and melatonin (20 mg/kg/d) was injected in the last 15 d. The results showed that dexamethasone treatment significantly enhanced oxidative stress (P < 0.05), while melatonin not only inhibited the oxidative stress but also notably enhanced the antioxidant enzymes superoxide dismutase (SOD), catalase activity (CAT), glutathione peroxidase (GSH-Px), and antioxidant genes CAT, superoxide dismutase 1 (SOD1), glutathione peroxidase 3 (GPX3), and recombinant peroxiredoxin 3(PRDX3) expression (P < 0.05). Melatonin treatment also markedly reduced 8-hydroxy deoxyguanosine(8-OHdG), malondialdehyde (MDA), and reactive oxygen species (ROS) levels (P < 0.05) and apoptotic genes Caspase-3, Bim, and Bax in the follicle. In the Dex+Mel group, the Bcl-2 and SOD1 protein levels were also increased (P < 0.05). Melatonin inhibited the forkhead Box Protein O1(FOXO1) gene and its protein expression (P < 0.05). In general, this investigation revealed that melatonin might decrease oxidative stress and ROS by enhancing antioxidant enzymes and genes, activating the antiapoptotic genes, and inhibiting the FOXO1 pathway in laying hens.

Is dexamethasone-induced muscle atrophy an alternative model for naturally aged sarcopenia model?

Primary sarcopenia is usually known as age-related skeletal muscle loss; however, other factors like endocrine, lifestyle and inflammation can also cause muscle loss, known as secondary sarcopenia. Although many studies have used different sarcopenia animal models for exploring the underlying mechanism and therapeutic approaches for sarcopenia, limited study has provided evidence of the relevance of these animal models. This study aims to investigate the similarity and difference in muscle qualities between primary and secondary sarcopenia mice models, using naturally aged mice and dexamethasone-induced mice. 21-month-old mice were used as naturally aged primary sarcopenia mice and 3-month-old mice received daily intraperitoneal injection of dexamethasone (20 mg/ kg body weight) for 10 days were used as secondary sarcopenia model. This study provided measurements for muscle mass and functions, including Dual-energy X-ray absorptiometry (DXA) scanning, handgrip strength test and treadmill running to exhaustion test. Besides, muscle contraction, muscle fibre type measurements and gene expression were also performed to provide additional information on muscle qualities. The results suggest two sarcopenia animal models shared a comparable decrease in forelimb lean mass, muscle fibre size, grip strength and muscle contraction ability. Besides, the upregulation of protein degradation genes was also observed in two sarcopenia animal models. However, only primary sarcopenia mice were identified with an early stage of mtDNA deletion. Collectively, this study evaluated that the dexamethasone-induced mouse model could be served as an alternative model for primary sarcopenia, according to the comparable muscle mass and functional changes. However, whether dexamethasone-induced mice can be used as an animal model when studying the molecular mechanisms of sarcopenia needs to be carefully evaluated. The purpose of sarcopenia research is to investigate appropriate treatments for reversing the loss of skeletal muscle mass and functions. Using animal models for the preclinical study could predict the safety and efficacy of the treatments. This study compared the typical age-related sarcopenia mice model and dexamethasone-induced secondary sarcopenia mice to provide evidence of the pathological and functional changes in the mice models.

The domino effect in inhaled carbon black nanoparticles triggers blood[sbnd]brain barrier disruption via altering circulatory inflammation

The bloodbrain barrier (BBB) impedes the influx of most compounds from the blood to the brain, and its integrity is a hallmark of nervous system health. Nanoparticles can cross the BBB through transcytosis, direct BBB impairment, reverse neuronal transport, and others. However, it is still ambiguous how the inhaled nanoparticles affect the BBB integrity. Herein, we evaluated the BBB disruption after carbon black nanoparticles (CBNPs) inhalation exposure and proposed a domino effect hypothesis to explain the extrapulmonary toxicity of inhaled nanoparticles. Mechanistically, inhaled CBNPs were internalized by alveolar macrophages and initiated the inflammatory storm in the pulmonary, resulting in the subsequent circulatory inflammation in the internal systemic environment and damage to the cerebrovascular tight junction with zonula occludens-1 (ZO-1) reduction. Moreover, an ex vivo biosensor assay elucidated that Wnt/β-catenin signaling was closely associated with cerebrovascular endothelial cell impairment. Furthermore, the reversal of BBB breakdown with intraperitoneal injection of dexamethasone supported that pulmonary and circulatory inflammation played a significant role in the domino effect of inhaled CBNPs. Therefore, this study demonstrates the mechanism of extrapulmonary toxicity of inhaled CBNPs and provides potential early intervention targets for the nervous system injury.

In vivo evaluation of wound healing effect and antioxidant properties of extracts and fractions of Gymnema sylvestre

Among the causes of mortality, wound healing remains a major problem that often results from imbalance between prooxidants and endogenous antioxidants in diabetics. The aim of this study was to evaluate the wound healing activity of Gymnema sylvestre in normoglycemic rat, and its antioxidant properties in type 2 diabetic rat. Evaluation of the healing properties of extracts (aqueous and methanol) and fractions (methylene chloride and methanol) G. sylvestre (10% of fraction or extract) were conducted in female normoglycemic rats and 1% fluoxetine was considered positive control using glycerin as a vehicle, while antioxidant assessments were conducted in male diabetic rats. Type 2 diabetes was induced in male rats by a high sucrose diet for 12 weeks followed by daily intraperitoneal injection of dexamethasone (8 mg/kg) for 5 consecutive days. Animals with a blood glucose above or equal to 140 mg/kg after 12 hours of fasting were considered diabetic. For the evaluation of wound healing 5 groups consisting of 3 female rats each were formed. Fluoxetine (1%), aqueous (Aq) and methanol (MeOH) extracts as well as methylene chloride (F1) and methanol (F2) fractions of the plant were administered at 10% via utopian application on wounds of about 2.5 cm in diameter. For the estimation of oxidative stress parameters in the diabetic rat, 7 groups of 5 animals each were formed, with three control groups including two negative control groups (normoglycemic and diabetic) receiving the vehicle orally (DMSO 3%) and a positive control group receiving metformin (Met, 200 mg/kg). The four experimental groups were treated orally with administration of Aq (100 mg/kg), MeOH, F1 and F2 (7.5 mg/kg). The different treatments were administered once a day for 14 consecutive days. Results showed that G. sylvestre promoted wound healing (P&gt;0.05) in the normoglycemic rat with a stronger effect for F2 and MeOH compared to the untreated group. In the diabetic rat, extracts and fractions of G. sylvestre significantly reduced (P&lt;0.001) the MDA level, while F1 significantly increased (P&lt;0.01) the activity of catalase (CAT) and reduced glutathione (GSH) compared to the untreated diabetes group on day one. These results revealed that G. sylvestre exhibited strong wound healing effects and justify the use of this in traditional pharmacopoeia.

Dexamethasone as an anti-cancer or hepatotoxic

The linkage between inflammation and oxidative stress in liver damage has been proven and is undeniable; dexamethasone with some antioxidants can reduce the toxicity of liver tissue. Due to the importance of cancer treatment, glucocorticoids' synergistic effect in inhibiting cancer cell growth is also investigated. Dexamethasone alone and combined with etoposide were tested at concentrations of 1, 5, and 10 μM to evaluate the potency of dexamethasone in inhibiting the growth of A549 cells using oxidative stress factors and DNA damage. Also, intraperitoneal injection of dexamethasone in rats was used to induce liver toxicity. Coenzyme Q10 at different concentrations (1, 10, and 50 mg/kg) was used as an antioxidant to assess the oxidative stress factors and measure Caspase-3 activity. The results showed that dexamethasone combined with etoposide could significantly inhibit the growth of cancer cells and induce apoptosis. Treatment of A549 cells using dexamethasone also inhibits cancer cells' growth by inducing oxidative stress and DNA damage. Dexamethasone also, by inducing oxidative stress and activation of caspase 3, ultimately causes hepatotoxicity. Treatment with different concentrations of CoQ10 showed improved mitochondrial function, antioxidant defense, and liver enzyme. The best effect of coenzyme Q10 on dexamethasone-induced hepatotoxicity is 50 mg/kg. As a result, dexamethasone (alone and combined with etoposide) has an anti-cancer effect by damaging DNA and inducing oxidative stress. Also, CoQ10 has antioxidant effects against dexamethasone-induced hepatotoxicity by improving mitochondrial function and reducing caspase-3 activity.

Extracts and fractions of Gymnema sylvestre restore liver and kidney function by regulating tissue and serum transaminases in the type 2 diabetic rat

Diabetes mellitus usually induce kidney and liver complications, characterized by an increase in transaminases activity. The aim of this study was to evaluate the activity of Gymnema sylvestre on the variation of tissue and serum transaminases activities in high sucrose diet and dexamethasone-induced diabetic rats. The animals were fed with high sucrose diet and 20% sugar water for 12 weeks then, received an intraperitoneal injection of dexamethasone (8mg/kg) once a day for 5 days between 07 and 08 am. After induction, the insulin sensitivity test was performed and the animals were divided into 7 groups. The experimental groups received extracts (aqueous and methanolic) and fractions (methylene chloride and methanol) of G. sylvestre once a day for 14 days. At the end of experiment, the animals were sacrificed and the blood, liver and kidney were collected for evaluation of transaminases and histopathology reduced by the plant. The activity of liver and kidney transaminases of the diabetic negative control (DNC) group on days 1 and 14 had significantly elevated (P&lt;0.001) compared with this of the normoglycemic negative control (NNC) group and the different treated groups. This trend was also observed at the serum level but only with ASAT. Histological analysis revealed hepatic leukocyte infiltrations and mesangial expansions in the urinary space in the DNC group on days 1 and 14. These tissue abnormalities were corrected in groups receiving extracts and fractions of G. sylvestre. This study suggests that the extracts and fractions of G. sylvestre restore tissue damage in diabetic rats.

Efficacy of Emilia coccinea aqueous extract on inhibition of α-amylase enzyme activity and insulin resistance in dexamethasone treated-rats

BackgroundDiabetes mellitus is one of the most common chronic metabolic diseases throughout the world, characterized by hyperglycemia and insulin resistance. The purpose of this study was to evaluate the effects of aqueous extract of Emilia coccinea (AEEC) leaves on dexamethasone-induced insulin resistance in rats and on in vitro α-amylase enzyme activity. MethodsInsulin resistance was induced by intraperitoneal injection of dexamethasone (1 mg/kg) for 8 days in rats. The animals were concomitant received extracts at doses of 107.5; 215; 430 mg/kg for this period. At the end of the treatment, blood glucose level, lipid profile, transaminases, triglyceride glucose (TyG) index, body mass and relative organ weight were evaluated. ResultsThe results showed that AEEC inhibits α-amylase enzyme with an IC50 of 34.10 μg/ml in vitro. AEEC significantly reduced blood glucose level, triglycerides, TyG index, total and LDL cholesterol, liver weight and increased HDL cholesterol. Moreover, it reduced ALAT and ASAT activity. These parameters were strongly modify by dexamethasone. ConclusionAEEC plays antidiabetic roles by ameliorating insulin resistance and reducing postprandial blood glucose level through α-amylase enzyme inhibition.

Acupoint catgut embedment may reduce airway inflammation reaction by down-regulating ICAM-1 and EOS by suppressing p38MAPK signaling in lung tissue of asthmatic rats

To observe the effect of acupoint catgut embedment(ACE) on expression of p38 mitogen activated protein kinase (p38MAPK), intercellular adhesion molecule-1(ICAM-1), interleukin-4 (IL-4) and eosinophils (EOS) in lung tissue of asthmatic rats, so as to explore its mechanism underlying improvement of asthma. Forty male Wistar rats were randomly divided into control, model, ACE and dexamethasone (DEX) groups, with 10 rats in each group. The asthmatic model was established by intraperitoneal injection of mixture suspension (1 mL) of ovalbumin (OVA,10%) and 10% Al (OH)3+ normal saline, followed by inhalation of atomized 1% OVA solution for 30 min, once daily for 2 weeks to trigger occurrence of asthmatic symptoms. The ACE was applied once to "Feishu" (BL13), "Dingchuan" (EX-B1) and "Danzhong" (CV17). Rats of the DEX group were given intraperitoneal injection of DEX once a day for 2 weeks. H.E. staining was used to evaluate histopathological changes of the lung tissue. The relative number of EOS in the bronchoalveolar lavage fluid (BALF) was detected by Wright Giemsa staining. The apoptosis level of EOS in the lung tissue was detected by TUNEL staining. The ultrastructural changes of EOS in the lung tissues were observed by transmission electron microscope (TEM). The expression of p38MAPK, ICAM-1 and IL-4 mRNAs in the lung tissue was detected by quantitative real-time PCR. Findings of optical microscope and TEM showed obvious bronchial deformation and inflammatory cell infiltration, rupture of EOS cell membrane, uneven cytoplasm with swelling and uneven density of eosinophilic granules in EOS of the model group, which was relatively milder in the ACE and DEX groups. Compared with the control group, the EOS number in BALF and the expressions of p38MAPK, ICAM-1 and IL-4 mRNAs in the lung tissue were significantly increased (P<0.01), and the apoptosis index of EOS in the lung tissue was significantly decreased (P<0.01) in the model group. After intervention, the EOS number in BALF and expression levels of p38MAPK, ICAM-1 and IL-4 mRNAs in the lung tissue of ACE and DEX groups were significantly decreased (P<0.01, P<0.05), as well as the apoptosis index of EOS in the lung tissue was significantly increased in both ACE and DEX groups (P<0.01) in comparison with the model group. The EOS number in BALF and expression of ICAM-1 mRNA were significantly lower in the DEX group than those in the ACE group (P<0.05). Catgut embedding at acupoints may alleviate the airway inflammatory response in asthma rats, which may be related with its effects in down-regulating p38MAPK signaling, ICAM-1 and IL-4 mRNA expression, reducing the aggregation of EOS, and promoting the apoptosis of EOS.

Proteomic Study of Low-Birth-Weight Nephropathy in Rats.

The hyperfiltration theory has been used to explain the mechanism of low birth weight (LBW)-related nephropathy. However, the molecular changes in the kidney proteome have not been defined in this disease, and early biomarkers are lacking. We investigated the molecular pathogenesis of LBW rats obtained by intraperitoneal injection of dexamethasone into pregnant animals. Normal-birth-weight (NBW) rats were used as controls. When the rats were four weeks old, the left kidneys were removed and used for comprehensive label-free proteomic studies. Following uninephrectomy, all rats were fed a high-salt diet until 9 weeks of age. Differences in the molecular composition of the kidney cortex were observed at the early step of LBW nephropathy pathogenesis. Untargeted quantitative proteomics showed that proteins involved in energy metabolism, such as oxidative phosphorylation (OXPHOS), the TCA cycle, and glycolysis, were specifically downregulated in the kidneys of LBW rats at four weeks. No pathological changes were detected at this early stage. Pathway analysis identified NEFL2 (NRF2) and RICTOR as potential upstream regulators. The search for biomarkers identified components of the mitochondrial respiratory chain, namely, ubiquinol-cytochrome c reductase complex subunits (UQCR7/11) and ATP5I/L, two components of mitochondrial F1FO-ATP synthase. These findings were further validated by immunohistology. At later stages of the disease process, the right kidneys revealed an increased frequency of focal segmental glomerulosclerosis lesions, interstitial fibrosis and tubular atrophy. Our findings revealed proteome changes in LBW rat kidneys and revealed a strong downregulation of specific mitochondrial respiratory chain proteins, such as UQCR7.

Evaluation of Dexamethasone-Induced Osteoporosis In Vivo Using Zebrafish Scales.

Glucocorticoid-induced osteoporosis (GIOP) is a major cause of secondary osteoporosis, and the pathogenic mechanisms of GIOP remain to be elucidated. Here, we show a rapid dexamethasone-induced osteoporosis animal model using zebrafish scales. Intraperitoneal injection of dexamethasone over a 5-day period suppressed the regeneration of scales. Furthermore, the circularity of the newly formed regenerated scales was also slightly reduced compared to that of the control group on day 5. The changes in bone-related enzymes, such as cathepsin K, tartrate-resistant acid phosphatase (TRAP) for bone resorption, and alkaline phosphatase (ALP) for bone formation, provide insight into the progression of bone diseases; therefore, we further developed a method to measure the activities of cathepsin K, TRAP, and ALP using zebrafish scales. We found that a lysis buffer with detergent at neutral pH under sonication efficiently helped extract these three enzymes with high activity levels. Interestingly, treatment with a dexamethasone injection produced considerably higher levels of cathepsin K activity and a lower Ca/P ratio than those in the control group, suggesting that dexamethasone increased osteoclast activity, with no significant changes in the activities of TRAP and ALP. Our GIOP model and enzyme assay method could help to design better treatments for GIOP.

Effects of Humulus lupulus L. and its active ingredient xanthohumol on preventing glucocorticoid-induced osteoporosis

Objective To explore the effects of Humulus lupulus L. extract (HLE) and xanthohumol (XN) on preventing glucocorticoid-induced osteoporosis (GIOP). Methods The GIOP model was established by intraperitoneal injection of dexamethasone (DEX). Bone microstructure, bone mineral density and serum biochemical indexes were evaluated by Micro-CT and ELISA kits. The levels of cells proliferation and ALP activity, and the expression of bone formation related proteins were assayed with primary osteoblasts injured by DEX. Results HLE and XN significantly alleviated the bone microstructure damage, enhanced the bone mineral density, and improved the trabecular parameters in GIOP mice. In vitro experiments showed that HLE and XN can prevent bone loss not only by improving cell proliferation and ALP activity, but also through increasing the expression of bone γ-glutamic acid-containing proteins (BGP), bone morphogenetic protein 2 (BMP-2) and runt-related transcription factor 2 (Runx-2). Conclusion This study confirmed that HLE and XN had anti-GIOP effects for the first time. It provides a new resource for the development of anti-osteoporosis medications.

The role of Serpina3n in the reversal effect of ATRA on dexamethasone-inhibited osteogenic differentiation in mesenchymal stem cells

BackgroundGlucocorticoid-induced osteoporosis (GIOP) is the most common secondary osteoporosis. Patients with GIOP are susceptible to fractures and the subsequent delayed bone union or nonunion. Thus, effective drugs and targets need to be explored. In this regard, the present study aims to reveal the possible mechanism of the anti-GIOP effect of all-trans retinoic acid (ATRA).MethodsBone morphogenetic protein 9 (BMP9)-transfected mesenchymal stem cells (MSCs) were used as an in vitro osteogenic model to deduce the relationship between ATRA and dexamethasone (DEX). The osteogenic markers runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), and osteopontin were detected using real-time quantitative polymerase chain reaction, Western blot, and immunofluorescent staining assay. ALP activities and matrix mineralization were evaluated using ALP staining and Alizarin Red S staining assay, respectively. The novel genes associated with ATRA and DEX were detected using RNA sequencing (RNA-seq). The binding of the protein–DNA complex was validated using chromatin immunoprecipitation (ChIP) assay. Rat GIOP models were constructed using intraperitoneal injection of dexamethasone at a dose of 1 mg/kg, while ATRA intragastric administration was applied to prevent and treat GIOP. These effects were evaluated based on the serum detection of the osteogenic markers osteocalcin and tartrate-resistant acid phosphatase 5b, histological staining, and micro-computed tomography analysis.ResultsATRA enhanced BMP9-induced ALP, RUNX2 expressions, ALP activities, and matrix mineralization in mouse embryonic fibroblasts as well as C3H10T1/2 and C2C12 cells, while a high concentration of DEX attenuated these markers. When DEX was combined with ATRA, the latter reversed DEX-inhibited ALP activities and osteogenic markers. In vivo analysis showed that ATRA reversed DEX-inhibited bone volume, bone trabecular number, and thickness. During the reversal process of ATRA, the expression of retinoic acid receptor beta (RARβ) was elevated. RARβ inhibitor Le135 partly blocked the reversal effect of ATRA. Meanwhile, RNA-seq demonstrated that serine protease inhibitor, clade A, member 3N (Serpina3n) was remarkably upregulated by DEX but downregulated when combined with ATRA. Overexpression of Serpina3n attenuated ATRA-promoted osteogenic differentiation, whereas knockdown of Serpina3n blocked DEX-inhibited osteogenic differentiation. Furthermore, ChIP assay revealed that RARβ can regulate the expression of Serpina3n.ConclusionATRA can reverse DEX-inhibited osteogenic differentiation both in vitro and in vivo, which may be closely related to the downregulation of DEX-promoted Serpina3n. Hence, ATRA may be viewed as a novel therapeutic agent, and Serpina3n may act as a new target for GIOP.

Protective Effects of Collagen Peptides on the Dexamethasone-Induced Immunosuppression in Mice

Collagen peptides are collagen derived products by enzymatic proteolysis, which is widely distributed in mammalian connective tissues. They have exhibited various bioactivities, including antioxidant activity, antihypertensive activity, improvement of joint pain, etc. However, the immunomodulatory effects of collagen peptides in the condition of immune suppression have not been elucidated. The objective of this study was to investigate the effects of collagen peptides on immune function in immunosuppressed mice. The immunosuppression was induced by intraperitoneal injection of dexamethasone for three days and at same time, collagen peptides (0, 300, 600, 900 mg/kg body weight) were given by gavage for seven days. On the day 8, the mice were sacrificed by decapitation. The body weight and the weights of thymus and spleen were recorded. Thymus and spleen indexes were calculated. The proliferation and interleukin-2 production of splenic T lymphocytes and ratio of CD4+/CD8+T lymphocytes in the peripheral blood were examined. Compared with the control mice, the body weight, thymus and spleen indexes, the proliferations and interleukin-2 production in T lymphocytes and the ratios of CD4+/CD8+T cells were significantly decreased in dexamethasone induced immunosuppressed mice. However, in collagen peptides treated mice, the thymus indexes, proliferation index, secretion of interleukin-2 and the ratio of CD4+/CD8+ were significantly increased compared with the mice in experimental model group. These results indicate that collagen peptides could play a protect role in glucocorticoid-induced immunosuppression.

Supplementation with Tetrahydrocurcumin Enhances the Therapeutic Effects of Dexamethasone in a Murine Model of Allergic Asthma

Background: Tetrahydrocurcumin (THC) is the major active metabolite of curcumin, which is a dietary factor derived from Curcuma species. Our previous study demonstrated a significant beneficial effect of THC in mice with allergic asthma. Glucocorticosteroids (GCs) are commonly used drugs in asthma. Whether THC supplementation could promote the beneficial effects of GC therapy on asthma has not yet been reported. The current study aimed to investigate the combined efficacy of GC and THC treatment in a mouse model of allergic asthma. Methods: BALB/c mice were randomly divided into 5 groups: the control group, ovalbumin (OVA)-induced group, and OVA-induced mice treated with dietary THC only, intraperitoneal injection of dexamethasone (DEX) only, or THC combined with DEX. The nasal symptoms, histopathological alterations of lung tissues, lung cytokine production, and Th cell subsets were assessed. Results: THC or DEX had beneficial effects on nasal symptoms and pathological lung changes, and the therapeutic effects between THC and DEX treatment were comparable. Importantly, compared to the monotherapy groups (THC or DEX only), the combination of THC and DEX showed a significantly reduced nasal rubbing frequency, lower mucus hyperproduction, lower Th2 and Th17 cell numbers as well as lower related cytokine levels (IL-4, IL-5, and IL-17A). Conclusions: Supplementation with THC can enhance the therapeutic effects of DEX to alleviate airway symptoms, lung inflammation, and the Th2 response. Our findings suggest that dietary administration of THC could act as an add-on therapy for asthma treated with GCs.

Biochemical and histopathological evidence for the beneficial effects of modafinil on the rat model of inflammatory bowel disease: involvement of nitric oxide pathway.

Inflammatory bowel disease is an intestinal disorder presented by recurrent inflammation in the gastrointestinal tract. It has been reported that modafinil, also known as an awakening drug, has anti-inflammatory characteristics. The objective of this experiment is to investigate the protective effects of modafinil on colitis induced by acetic acid in rat and the involvement of nitric oxide pathway. Colitis was induced by intra-rectal instillation of 1ml acetic acid (4%). After one h of colitis induction (first day), intraperitoneal injection of dexamethasone (1mg/kg), modafinil (50, 100, and 150mg/kg), nitric oxide synthase inhibitors (NOS)-N (G)-nitro-L-arginine methyl ester (L-NAME) 10mg/kg, 7-nitroindazole 40mg/kg, and aminoguanidine 50mg/kg-was performed and continued for 2 consecutive days. Ultimately, macroscopic, microscopic, and biochemical assessments were performed. While induction of colitis caused severe macroscopic lesions, administration of dexamethasone and modafinil (100 and 150mg/kg) significantly improved macroscopic ulcers. Interestingly, the combination of modafinil with NOS inhibitors reversed the beneficial effects of modafinil on macroscopic destructions. In addition, the elevated level of interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) was decreased by modafinil. However, treatment with NOS inhibitors before modafinil neutralized the anti-inflammatory influence of modafinil. Additionally, histological disorders emerged by acetic acid in colon tissue remarkably were disappeared after treatment with modafinil. In conclusion, modafinil has a protective effect on injuries induced by acetic acid in the colon of rat, which is presumably via the inhibition of inflammatory cascade and mediation of NO pathway.

Protective Effects of Aqueous Extract of Baillonella toxisperma Stem Bark on Dexamethasone-Induced Insulin Resistance in Rats

The aim of this study was to evaluate the effects of the aqueous extract of Baillonella toxisperma stem bark on dexamethasone-induced insulin resistance in rats. A quantitative phytochemical study was done on the aqueous extract of Baillonella toxisperma for the total phenol, flavonoid, and flavonol determination. Insulin resistance was induced by intraperitoneal injection of dexamethasone (1 mg/kg) for 8 days, one hour before oral administration of different treatments (extract at doses of 60, 120, and 240 mg/kg and metformin at 40 mg/kg). During the test, body weight and blood glucose level were evaluated on days 1 and 8. At the last day of treatment, the glucose tolerance test was performed in rats; after that, blood samples were collected for triglycerides, total cholesterol, LDL and HDL cholesterols, transaminases (ALT and AST), and total protein level determination. Organs (heart, liver, pancreas, and kidneys) were also collected for the relative organ weight determination. The results showed that the aqueous extract of B. toxisperma is rich in total phenols, flavonoids, and flavonols. This extract significantly reversed the metabolic alterations (lipid profile, protein level, and transaminase activity) induced by dexamethasone in rats. At doses of 120 and 60 mg/kg, Baillonella toxisperma also significantly decreases (p < 0.05; p < 0.01) postprandial hyperglycemia in insulin resistance rats. The results suggest that Baillonella toxisperma can manage insulin resistance and may be useful for the treatment of type 2 diabetes mellitus.

Effect of protracted dexamethasone exposure and its withdrawal on rocuronium-induced neuromuscular blockade and sugammadex reversal: an ex vivo rat study

Studies have reported that protracted dexamethasone treatment induces resistance to nondepolarizing neuromuscular blocking agents (NMBAs) and the association with nicotinic acetylcholine receptors in the diaphragm of rats. Here, we investigated the effect of protracted dexamethasone administration on the sensitivity to rocuronium and the recovery profile when reversed by sugammadex; additionally, we observed the recovery period of pharmacodynamic change after withdrawal. Sprague-Dawley rats received daily intraperitoneal injections of dexamethasone or saline for 14 days. On days 1, 3, and 7 after the last dexamethasone treatment (Dexa1, Dexa3, and Dexa7, respectively) or 1 day after saline (control group), the phrenic nerve-hemidiaphragm preparation was dissected for assay. The dose-response curve of rocuronium in Dexa1 was shifted to the right compared to controls, but curves in Dexa3 and Dexa7 were not significantly different. Groups were not significantly different in attaining the train-of-four ratio ≥ 0.9, but the recovery index in Dexa7 was shorter than that in control and Dexa1. Recovery profiles (period of sugammadex reversal) were not correlated with resistance properties but rather with total administered drugs (binding capacity of NMBAs and sugammadex). Protracted dexamethasone exposure induced resistance to rocuronium but seemed to have no effect on sugammadex reversal in the rat diaphragm.