Male Sprague-Dawley Rats Research Articles

Relationship between the ratio of increase in lean tissue to body weight gain and energy required to gain body weight in growing rats.

Although the energy stored in the lean tissue (LT) and adipose tissue (AT) is well known, the energy required to synthesize these tissues is obscure. Theoretically, the energy at the point at which ΔLT/Δ body weight (BW) reaches 100% on a regression line, which indicates the relationship between ΔLT/ΔBW and the energy required for BW gain, is considered to be the energy expended to synthesize LT. Therefore, we investigated this relationship in rats. Rats were fed diets with different ratios of protein, fat, and carbohydrates because their ΔLT/ΔBW values were expected to be different. Six-week-old male Sprague-Dawley rats had ad libitum access to normal (N, n = 6), high-fat (HF, n = 7), or high-protein (HP, n = 8) diets for 4 weeks. The ΔLT/ΔBW was 0.77 in the N group, 0.70 in the HF, and 0.87 in the HP groups, respectively. The average energy required to gain BW was 8.8 kJ/g in the N group, 7.0 kJ/g in the HF group, and 11.3 kJ/g in the HP group. We observed a positive correlation between ΔLT/ΔBW and energy required for BW gain. The regression line demonstrated that the energy expended to synthesize LT was 13.9 kJ/g and AT was -7.9 kJ/g. Therefore, combined with the energy stored in LT, the energy required to accumulate LT is approximately 19 kJ/g, whereas the energy to accumulate AT could not be elucidated.

Repeated, High-dose Fentanyl Administration in Rats Reveals Minimal Tolerance to Unconsciousness, Bradycardia, Muscle Rigidity and Respiratory Depression

Background: Fentanyl is a synthetic opioid that is widely used in anesthesiology, but its illicit use is rapidly increasing. At high doses fentanyl induces unconsciousness and muscle rigidity, the mechanisms of which are poorly understood. Since animal models are needed to study these effects, the aim of this study was to establish a rat model of fentanyl abuse and investigate the effects of repeated high-dose fentanyl injections on loss of righting reflex, heart rate, respiratory depression, muscle, and brain activity. Methods: Male and female Sprague-Dawley rats were studied (n=40). A bolus of 100µg/kg fentanyl was administered intravenously twice a week for five consecutive weeks. Time to return of righting reflex (RORR) after fentanyl injection and changes in EMG/EEG activity as well as heart rate were analyzed. Additionally, arterial blood gas analysis for evaluation of ventilation was performed. Mixed-effect models with Dunnet’s test and effect sizes were used for statistical analysis. Results: Repeated injections resulted in a U-shaped change in time to RORR with the longest latency after the first exposure (median: 50[1st-3rd quartile:36-56]min) and the shortest after the fifth exposure (16[13-33]min). Following fentanyl administration, heart rate dropped immediately by 225[95%CI: 179, 271]bpm (F=3952.16, p<.001), while EMG activity increased by 291[95%CI: 212, 370]% (F=27.51, p<0.001) and PaCO2 inclined by 49.4[95%CI: 40.6, 58.2]mmHg (F=75.97, p<0.001) within 5 minutes after injection. Additionally, pH decreased by 0.48[95%CI: 0.41, 0.54] (F=142.00, p<0.01), and PaO2 decreased by 50.4[40.8, 60.0]mmHg (F=57.90, p<0.001). Repeated fentanyl exposures did not significantly affect the extent of these changes (EMG: F=1.63, p=0.237; PaCO2: F=1.23, p=0.312; HR: F=1.05, p=0.400; pH: F=3.05, p=0.066; pO2: F=3.35, p=0.052). EEG analysis revealed that repeated fentanyl exposures elicited significantly higher absolute power in frequencies >20Hz as indicated by an area under the receiver operator characteristics curve >0.7. Conclusion: We established a rodent model of repeated, high-dose fentanyl administration. Overall, significant evidence of tolerance was not observed after ten exposures of high-dose fentanyl for any of the analyzed parameters. These results suggest that tolerance does not develop for fentanyl-induced unconsciousness, muscle rigidity, or respiratory depression.

Single-cell RNA sequencing uncovers heterogenous immune cell responses upon exposure to food additive (E171) titanium dioxide

The prospective use of food additive titanium dioxide (E171 TiO2) in a variety of fields (food, pharmaceutics, and cosmetics) prompts proper cellular cytotoxicity and transcriptomic assessment. Interestingly, smaller-sized E171 TiO2 can translocate in bloodstream and induce a diverse immunological response by activating the immune system, which can be either pro-inflammatory or immune-suppressive. Nevertheless, their cellular or immunologic responses in a heterogeneous population of the immune system following exposure of food additive E171 TiO2 is yet to be elucidated. For this purpose, we have used male Sprague-Dawley rats to deliver E171 TiO2 (5 mg/kg bw per day) via non-invasive intratracheal instillation for 13 weeks. After the 4 weeks recovery period, 3 mL of blood samples from both treated and untreated groups were collected for scRNAseq analysis. Firstly, granulocyte G1 activated innate immune response through the upregulation of genes involved in pro-inflammatory cytokine mediated cytotoxicity. Whereas NK cells resulted in heterogeneity role depending on the subsets where NK1 significantly inhibited cytotoxicity, whereas NK2 and NK3 subsets activated pro-B cell population & inhibited T cell mediated cytotoxicity respectively. While NKT_1 activated innate inflammatory responses which was confirmed by cytotoxic CD8+ T killer cell suppression. Similarly, NKT_2 cells promote inflammatory response by releasing lytic granules and MHC-I complex inhibition to arrest cytotoxic T killer cell responses. Conversely, NKT_3 suppressed inflammatory response by release of anti-inflammatory cytokines suggesting the functional heterogeneity of NKT subset. The formation of MHC-I or MHC-II complexes with T-cell subsets resulted in neither B and T cell dysfunction nor cytotoxic T killer cell inhibition suppressing adaptive immune response. Overall, our research offers an innovative high-dimensional approach to reveal immunological and transcriptomic responses of each cell types at the single cell level in a complex heterogeneous cellular environment by reassuring a precise assessment of immunological response of E171 TiO2.Graphical

Evaluation of the effect of melatonin treatment on telomere length of the retinal pigment epithelium in streptozotocin-induced diabetic rat model

ObjectivesWe aimed to investigate the effect of diabetic retinopathy and melatonin treatment on the relative telomer lengths (RTL) in retinal pigment epithelium (RPE) cells in a streptozotocin-induced diabetic rat model.BackgroundTL can be used to evaluate diabetes mellitus, its complications, and the effectiveness of its treatment. However, TL assessment has not been performed in retinal cells in a diabetic retinopathy model until now.MethodsForty Sprague-Dawley male rats were randomly divided into four groups. The experimental groups were: Control Group (C): non- diabetic rats; Diabetes Mellitus Group (DM): rats induced to diabetes without treatment; Melatonin and Diabetes Mellitus Group (Mel + DM): rats induced to diabetes and after confirmation, treated with melatonin; Melatonin Group (Mel): rats were not induced to diabetes, treated with melatonin. Diabetes was induced by intraperitoneal administration of streptozotocin solution after 12 h food fasting. For eight weeks after the diabetes was induced, melatonin was administered via subcutaneous injection at a dose of 10 mg / kg. RTLs were measured by qPCR method with modifications. The comparison of averaged data among groups was performed using least significant difference (LSD) and Kruskal – Wallis Test and One way ANOVA test.ResultsRTL was significantly similar in control and melatonin group. RTL was thinnest in DM group, in addition melatonin treatment significantly prevented the RTL shortening in DM + Mel group (p = 0.031).ConclusionWe demonstrated that diabetic retinopathy led to the shortening of RTL in RPE cells in rats and melatonin treatment prevents this shortening.

PM2.5 Exposure Triggers Hypothalamic Oxidative and ER Stress Leading to Depressive-like Behaviors in Rats

Epidemiological studies have linked fine dust pollution to depression, yet the underlying mechanisms remain unclear. Oxidative stress and endoplasmic reticulum (ER) stress are known contributors to depression, but their induction by particulate matter (PM), particularly PM2.5, in animal models has been limited. This study aimed to establish a rat model of PM2.5-induced depression-like behaviors and elucidate the underlying molecular mechanisms. Adult male Sprague–Dawley rats received daily intranasal PM2.5 for four weeks. Behavioral assessments, including the open field test (OFT), forced swim test (FST), and light-dark box (LDB) test, were conducted weekly. PM2.5-exposed rats displayed depressive-like behaviors, particularly in the FST, reflecting decreased motivation and learned helplessness. Molecular analyses indicated a specific increase in ER stress markers (CHOP, eIF2α, GRP78, and P16) and NOX4 in the hypothalamus, while other brain regions (striatum, cortex, and hippocampus) were not as pronounced. Additionally, PM2.5 exposure reduced tyrosine hydroxylase (TH) levels in the hypothalamus, suggesting impaired dopamine synthesis. These findings indicate that PM2.5 induces depressive-like behaviors via hypothalamic ER stress and oxidative stress pathways, leading to dopaminergic dysfunction. Targeting oxidative and ER stress within the hypothalamus may offer new therapeutic strategies for treating depression associated with environmental pollutants.

Human placental stem cell-based therapies for prevention of abdominal adhesions: A prospective randomized preclinical trial.

Abdominal adhesions are networks of fibrotic tissues that form between organs postoperatively. Current prophylactic strategies do not reproducibly prevent adhesive small bowel obstruction across the entire abdomen. Human placental-derived stem cells produce an anti-inflammatory secretome that has been applied to multiple fibrosing diseases. The purpose of this project is to test human placental stem cell (hPSC)-based therapies for prevention of abdominal adhesions in a clinically relevant rat model. Fifty-four (n = 54, n = 6/group) male Sprague-Dawley rats (250-350 g) underwent model creation and treatment randomization under anesthesia. Experimental groups included human placental-derived stem cells (hPSC, 5 × 106 cells/10 mL Plasmalyte A), human placental-derived stem cells in a hyaluronic acid (HA-Mal-hPSC) hydrogel, the human placental-derived stem cell secretome from conditioned media in 10 mL Plasmalyte A, human placental-derived stem cells' conditioned media in a hyaluronic acid (HA-Mal-CM) hydrogel, Plasmalyte A (media alone, 10 mL), hyaluronic acid hydrogel alone (HA-Mal), Seprafilm (Baxter, Deerfield, IL), and the control groups, model with no treatment (MNT) and sham animals. Treatments were administered intraperitoneally, and the study period was 14 days postoperation. Adhesions were scored at necropsy and analyzed as the difference between means of an index statistic (Animal Index Score) versus MNT. Underlying molecular mechanisms were explored by functional genomic analysis and histology of peritoneal tissues. Hyaluronic acid hydrogel alone, HA-Mal-CM hydrogel, and Seprafilm significantly reduced the overall appearance of abdominal adhesions by mean Animal Index Score at 14 days versus MNT. Human placental stem cell, HA-Mal-hPSC hydrogel, HA-Mal-CM hydrogel, HA-Mal hydrogel alone, and Seprafilm significantly reduced the collagen content of injured peritoneal tissues. Human placental stem cell and HA-Mal-hPSC hydrogel suppressed expression of the most profibrotic genes. Conditioned media, HA-Mal hydrogel alone, and media alone significantly altered the expression of proteins associated with peritoneal fibrotic pathways. Human placental stem cell-based therapies reduce abdominal adhesions in a prospective randomized preclinical trial. This effect is supported by suppression of profibrotic genomic and proteomic pathways.

Histomorphometric analysis of external apical root resorption using L-loops and different intrusive forces

ABSTRACT Purpose This study aimed to conduct a histomorphometric analysis on the impact of varying intrusive forces on external apical root resorption (EARR) in rat molars, using an L-loop was employed to apply intrusion forces, artificially inducing EARR in the maxillary left first molar (M1) of rats. Materials and methods The L-loop was bent on a plaster rat model using stainless steel round wires with diameters of 0.014 and 0.016 inches. Using a universal test force measuring device, L-loops were calibrated to 4 N/mm and 6 N/mm for the 0.014-inch and 0.016-inch diameter stainless steel round wires, respectively. Fifteen-week-old Sprague-Dawley (SD) male rats were used and divided into the control (no loop) and experimental (0.014 and 0.016) groups (n = 5 for each group). The L-loop was attached to the left maxillary molar, applying an intrusive force to M1. After 15 days, the rats were euthanized. Maxillary bones were analysed using micro-computed tomography (μCT), evaluating M1 intrusive distance of vertical tooth movement and counting the number of tartrate-resistant acid phosphatase (TRAP)-positive cells on the surface of the mesial root apex and alveolar bone. Results The L-loop groups exhibited significantly increased M1 intrusive distance and TRAP-positive cell counts compared to controls. Specifically, the 0.016 group demonstrated greater M1 intrusive distance and more TRAP-positive cells than the 0.014 group. The M1 intrusive distance and TRAP-positive cells increased when intrusive forces were applied using L-loops of different diameters. Conclusion Greater intrusive forces enhance TRAP-positive cell activity, influencing EARR and vertical tooth movement.

Histological Evaluation of the Effects of Intra-Articular Injection of Caffeic Acid on Cartilage Repair in a Rat Knee Microfracture Model.

BACKGROUND Cartilage injuries are challenging to treat due to limited self-healing. Standard treatments often lead to the formation of less durable fibrocartilage. Caffeic acid phenethyl ester (CAPE), a polyphenolic compound, can improve cartilage repair. This animal study aimed to evaluate the histological effects of intra-articular injection of CAPE on cartilage repair in a rat model of microfracture of the knee joint. MATERIAL AND METHODS Twenty-four male Sprague-Dawley rats were divided into 4 groups. A cartilage defect was created in all groups, but Group A received no further intervention. Group B underwent a microfracture. Group C received intra-articular CAPE in the presence of a defect, without microfracture. Group D underwent both microfracture and CAPE treatment. Also, each rat underwent bilateral surgery, with one knee receiving CAPE (150 µg/kg) and the other receiving a control solution. After 28 days, histological analysis was performed on the cartilage tissue samples obtained from the defect sites by using the International Cartilage Research Society (ICRS-I and -II) visual assessment scale. Statistical analysis was performed using appropriate tests to compare histological scores between groups, with significance set at P<0.05. RESULTS Intra-articular CAPE significantly improved histopathological outcomes across several parameters, including reduced inflammation (P<0.05), enhanced tissue morphology (P<0.05), and improved cartilage matrix staining (P<0.05). No significant difference was observed in chondrocyte clustering or surface architecture among the groups. CONCLUSIONS Intra-articular CAPE enhances cartilage healing by improving tissue morphology and cartilage matrix quality.

Oxidative and Endoplasmic Reticulum Stress Mediate Testicular Injury in a Rat Model of Varicocele.

Evidence of endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) have been increasingly reported in varicocele (VCL)-affected testes. However, the mechanisms by which oxidative stress (OS) and ER stress contribute to male infertility in VCL remain unclear. In this study, male Sprague-Dawley rats were divided into a control group, which underwent sham surgery, and a VCL group, in which VCL was surgically induced. Eight weeks postoperatively, the VCL group exhibited significant testicular damage and sperm abnormalities. Western blot analysis revealed upregulation of ER stress-related proteins and downstream apoptotic markers in the VCL group. For further investigation, we developed an in vitro oxidative stress model using GC-2 cells treated with 400 µM hydrogen peroxide (H2O2) for 12h. Cells were also treated with either an ER stress inducer or inhibitor. We found that treatment with H2O2 and the ER stress inducer significantly reduced GC-2 cell viability and increased reactive oxygen species (ROS) production, ER stress, and apoptosis. Conversely, treatment with the ER stress inhibitor 4-phenylbutyric acid (4-PBA) alleviated these effects. Our findings suggest a strong association between VCL-induced redox imbalance and ER stress-related injury driven by the UPR in this rat model. Furthermore, 4-PBA effectively reduced germ cell damage induced by ROS-mediated ER stress, offering potential therapeutic insights for treating VCL-related infertility.

Development of a UPLC-MS/MS method for the determination of sulfatinib and its no interaction with myricetin in rats.

Sulfatinib is a novel oral tyrosine kinase inhibitor (TKI) with selective inhibition of fibroblast growth factor (FGFR), colony-stimulating factor 1 receptor (CSF-1R) and vascular endothelial growth factor receptor (VEGFR) 1, 2, and 3. It has been approved for the therapy of neuroendocrine tumors arising in the non-pancreatic (December 2020) and pancreatic (June 2021) glands. Until now, there has no research on the determination of sulfatinib in biological medium by ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method. The current study validated a sensitive and reliable quantitative detection of sulfatinib in plasma using UPLC-MS/MS for the first time, and investigated the interaction with myricetin in rats. Acetonitrile was used to precipitate the plasma protein, and lenvatinib was employed as the internal standard (IS). The method demonstrated that sulfatinib presented high linearity over the concentration of 11-2,000ng/mL with the lower limit of quantification (LLOQ) of 1ng/mL. It was validated methodologically that the precision, matrix effect, stability, accuracy and extraction recovery were all within the allowable values. Moreover, male Sprague-Dawley (SD) rats were assigned randomly to assess the interaction between sulfatinib (30mg/kg) and myricetin (50mg/kg). Nevertheless, no significant differences of the main pharmacokinetic parameters were revealed. This may be due to insufficient doses of myricetin, or failure of myricetin to act in a timely manner in vivo. The findings contributed to a better understanding of the metabolism and drug-drug interaction of sulfatinib, but the presence or absence of interactions needs to be confirmed by further studies.

Retrograde evoked compound action potentials as an alternative for close-loop spinal cord stimulation

Evoked compound action potential (ECAP) is an important parameter in close-loop spinal cord stimulation (SCS). The recording electrode is typically positioned proximal to the stimulation electrode to capture the antegrade ECAP signals generated by ascending fibers. However, relatively little research has been conducted on retrograde ECAPs. This study investigated retrograde ECAPs using custom-made epidural electrodes in 11 adult male Sprague–Dawley rats. Results show that the average motor threshold (MT) and ECAP threshold (ECAPT) for 11 anesthetized rats were 218.18 ± 69.54 μA and 107.27 ± 27.96 μA, respectively. The ECAP amplitudes increased with increasement of the stimulation current and pulse width (PW), and were larger in awake rats than in anesthetized rats. Additionally, aside from ECAPs recorded by a commercial electrophysiological recorder, ECAPs were also recorded by a custom-made amplifier for the purpose of future long-term implantation, but the custom-made amplifier showed lower signal to noise ratio than the commercial amplifier. In conclusion, this study illustrates that retrograde ECAP may also be considered as a feedback signal for close-loop SCS and more sophisticated ECAP recording circuits are needed to form a close-loop system.

Losartan attenuates sex-dependent hypertension, neuroinflammation, and cognitive impairment in the aging male sprague-dawley rat.

The prevalence of hypertension increases with age and is the leading modifiable risk factor for cognitive impairment and dementia. At present, the neural mechanisms promoting hypertension across the lifespan are incompletely understood. Using the Sprague-Dawley (SD) rat as a model of normal aging, we hypothesized (1) blood brain barrier (BBB) disruption and neuroinflammation in the paraventricular nucleus (PVN) of the hypothalamus enhances sympathetic tone and contributes to age-dependent hypertension, (2) age-dependent hypertension is associated with cognitive impairment, and (3) lowering blood pressure in aged rats with established hypertension improves cognitive function. We found male, but not female, rats develop age-dependent hypertension with enhanced sympathetic tone, BBB disruption, and neuroinflammation in the PVN. Aged hypertensive male rats also showed impairments in recognition and spatial memory. Utilizing pharmacological interventions, blood pressure was lowered in male rats with established hypertension using either losartan (LOS) or hydrochlorothiazide. However, only losartan improved recognition memory. Further, LOS reduced BBB disruption, microglial activation, astrocyte reactivity, and proinflammatory cytokine expression in the PVN which we speculate contributes to a decrease in blood pressure. These data show SD rats develop age-dependent hypertension and cognitive impairment in a sex-dependent manner. However, not all antihypertensive agents improve cognitive function equally as only losartan, an angiotensin II type 1 receptor antagonist (AT1R) improved recognition memory. Thus, AT1R antagonists represent a potential therapeutic approach for treating cognitive decline in the aging population.

A reliable strategy for establishment of an animal model of diabetic cardiomyopathy: Induction by a high-fat diet combined with single or multiple injections of low-dose streptozotocin

BackgroundDiabetic cardiomyopathy (DCM) is one of the leading causes of death in patients with diabetes mellitus (DM). This study aimed to identify a reliable method for establishing an animal model of DCM for investigation of new targets and treatments. MethodsEighty-four 4-week-old male Sprague–Dawley rats were randomly allocated to receive a normal diet or a high-fat diet (HFD) in an approximate ratio of 1:3. At 9 weeks of age, rats in the HFD group received streptozotocin (STZ) 30 mg/kg by intraperitoneal injection and rats in the control group received the same volume of buffer solution. The rodent model of DM was deemed to be successfully established when a random blood glucose measurement was >16.7 mmol/L on three consecutive occasions. If necessary, STZ was readministered. ResultsThree of the 64 rats in the HFD group died after a second STZ injection. DM was induced in 14, 39, and 8 rats after one, two, and three injections, respectively, with cumulative success rates of 21.9 %, 82.8 %, and 95.3 %. Three months later, the rats with DM showed persistent hyperglycemia and insulin resistance and developed histopathological changes indicating cardiac hypertrophy, myocardial fibrosis, and diastolic dysfunction. The metabolic and cardiac histopathological changes were consistent regardless of whether DM was induced by one, two, or three injections of STZ. ConclusionAn HFD combined with one or more intraperitoneal injections of low-dose STZ is a straightforward and reliable method for inducing DCM in rats. When a single dose of STZ fails to induce DM, repeated injections can be considered.

Protective effect of ascorbic acid against renal injury induced by 3-chloropropane-1,2-diol-dipalmitate in rats.

3-monochloropropane-1,2-diol esters (3-MCPDE) are a group of contaminants which are mainly formed during heat processing of edible oil and fat-based foods. The kidney is the primary target organ for the toxic effects of 3-MCPDE. 3-MCPD-di-palmitate exists in a variety of oils and fats, and is the most common and relatively high proportion of 3-MCPDE. In this study, we investigated the protective effect of ascorbic acid on 3-MCPD-di-palmitate-induced renal injury in rats. Thirty 8-week-old male Sprague-Dawley rats were randomly divided into 5 groups, namely control, 3-MCPD-di-palmitate (240 mg/kg·bw), 3-MCPD-di-palmitate (240 mg/kg·bw) + ascorbic acid (100 mg/kg·bw), 3-MCPD-di-palmitate (240 mg/kg·bw) + ascorbic acid (200 mg/kg·bw) and 3-MCPD-di-palmitate (240 mg/kg·bw) + ascorbic acid (500 mg/kg·bw). These treatments were administered via gavage for a duration of 4 weeks. The effects of ascorbic acid on 3-MCPDE-induced kidney injury in rats were investigated by evaluating the kidney index, renal function (BUN, CRE), renal histopathology, oxidative stress markers (ROS, GSH, MDA, and T-AOC), DNA oxidation marker (8-OHdG), and activities of Caspase 3 and 9. The results showed that the exposure to 3-MCPDE significantly increased the kidney index, BUN and CRE levels, ROS and MDA levels, 8-OHdG levels, and activities of Caspase 3 and 9, while decreasing GSH and T-AOC. The combined treatment with 3-MCPDE and ascorbic acid can effectively restore the aforementioned parameters. The present study concluded that ascorbic acid effectively attenuates the renal apoptosis and oxidative homeostasis induced by 3-MCPDE uptake thereby intervening in renal injury.

Xiao-xu-ming Decoction Improved Synaptic Damage after Acute Cerebral Ischemia and Reperfusion via JAK2/STAT3 Pathway in Rats.

Ischemic stroke is an important cause of death and disability worldwide. Xiao-xu-ming Decoction (XXMD) is a classic prescription for the treatment of stroke patients, which has been widely used in China and has significant therapeutic effect, but the therapeutic target and mechanism are still unclear. The current study aimed to investigate temporal alternation of synaptic damage and the protective effects of XXMD on synaptic damage following cerebral ischemia and reperfusion in vivo. Adult male Sprague-Dawley (SD) rats subjected to 90 mins of middle cerebral artery occlusion (MCAO) and subsequent reperfusion at various time points. Neurobehavioral function was assessed using modified neurological severity scores (mNSS), while pro-inflammatory cytokine levels were measured using ELISA kits. Histological assessment involved silver staining and Luxol Fast Blue (LFB) staining, and the ultrastructural alterations in neurons and synapses were examined using a transmission electron microscope (TEM). Golgi-cox staining was used to evaluate the density of dendritic spines. Levels of synapse-related proteins were quantified via immunofluorescence staining and Western blotting. Additionally, JAK2/STAT3 pathway related protein levels were assessed using Western blotting. In the second part, the rats were randomly divided into sham operation group, 24 hours of reperfusion group, and XXMD group. The ultrastructural alterations and dendrite spine density of synapses were observed by TEM and Golgi-Cox staining respectively, and the expression levels of SYN, PSD95, GAP43, p-JAK2 and p-STAT3 were evaluated by WB. Findings included deteriorated neurobehavioral function, increased release of IL-6, IL-1β, and TNFα, and time-dependent neuronal and synaptic damages during the initial phase of ischemia and reperfusion. At the ultrastructural level, neurons and synapses exhibited structural failure in the peri-infarct cortex. In addition, golgi-cox staining showed dendritic density in ischemic cortex significantly reduced after cerebral ischemia and reperfusion. Moreover, significant reductions in SYN, PSD95, and GAP43 expression levels, along with increases in p-JAK2 and p-STAT3 expression levels, were observed after cerebral ischemia and reperfusion. Meantime, XXMD significantly reduced synaptic impairment and down-regulated SYN, GAP43, PSD95 expression and phosphorylation expression of JAK2 and STAT3 following MCAO and 24 hours of reperfusion. Collectively, these results indicates XXMD may play a neuroprotective role in reducing synaptic damage via JAK2/STAT3 signaling pathway.

Dorsal raphe to basolateral amygdala corticotropin-releasing factor circuit regulates cocaine-memory reconsolidation.

Environmental stimuli elicit drug craving and relapse in cocaine users by triggering the retrieval of strong cocaine-related contextual memories. Retrieval can also destabilize drug memories, requiring reconsolidation, a protein synthesis-dependent storage process, to maintain memory strength. Corticotropin-releasing factor (CRF) signaling in the basolateral amygdala (BLA) is necessary for cocaine-memory reconsolidation. We have hypothesized that a critical source of CRF in the BLA is the dorsal raphe nucleus (DR) based on its neurochemistry, anatomical connectivity, and requisite involvement in cocaine-memory reconsolidation. To test this hypothesis, male and female Sprague-Dawley rats received adeno-associated viruses to express Gi-coupled designer receptors exclusively activated by designer drugs (DREADDs) selectively in CRF neurons of the DR and injection cannulae directed at the BLA. The rats were trained to self-administer cocaine in a distinct environmental context then received extinction training in a different context. Next, they were briefly re-exposed to the cocaine-predictive context to destabilize (reactivate) cocaine memories. Intra-BLA infusions of the DREADD agonist deschloroclozapine (DCZ; 0.1 mM, 0.5 µL/hemisphere) immediately after memory reactivation attenuated cocaine-memory strength, relative to vehicle infusion. This was indicated by a selective, DCZ-induced and memory reactivation-dependent decrease in drug-seeking behavior in the cocaine-predictive context in DREADD-expressing males and females at test compared to respective controls. Notably, BLA-projecting DR CRF neurons that exhibited increased c-Fos expression during memory reconsolidation co-expressed the glutamatergic neuronal marker, vesicular glutamate transporter 3. Together, these findings suggest that the DRCRF → BLA circuit is engaged to maintain cocaine-memory strength after memory destabilization, and this phenomenon may be mediated by DR CRF and/or glutamate release in the BLA.

An Experimental Insight Into the Role of Agomelatine in Renal Ischemia/Reperfusion Injury.

Acute kidney injury (AKI) is one of the leading causes of chronic kidney disease and accounts for 50%-75% of mortality following renal pathologies or organ transplantation. Ischemia‒reperfusion injury (IRI) involves an interrupted blood supply to organs and the kidney; IRI exacerbates AKI development. Owing to several pharmacological treatment methods, AKI still has a poor prognosis, and novel therapeutic options are needed. Agomelatine (AGM) is a melatonin receptor agonist (MT1 and MT2) with increased bioavailability and lipophilicity. In this study, we aimed to investigate the antioxidant and anti-inflammatory effects of AGM in experimental renal IRI via long-term and short-term applications. Sixty male Sprague-Dawley rats were randomly divided into six groups (n = 10): the control, I/R, AGM20S, AGM40S, AGM20L, and AGM40L groups. Following the establishment of the renal IRI model, the rats received agomelatine at 20 and 40 mg/kg orally, and agomelatine solvent (hydroxyethylcellulose) was used as a vehicle. At the end of the experiment, blood samples and renal tissues were harvested for histopathological and biochemical analysis. Urea, creatinine, tumor necrosis factor (TNF-α), and interleukin-1 beta (IL-1β) levels were measured in blood serum samples. Malondialdehyde (MDA) levels and increased superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSHPx), and total glutathione (GSH) levels were measured in renal tissue supernatants. Our biochemical results indicated that AGM reduced creatinine, TNF-α, IL-1β, and malondialdehyde levels and increased SOD, CAT, GSHPx, and total GSH levels. Agolematine reduced infiltration, intratubular hemorrhage, and intratubular cast formation histopathologically. Our results suggest that AGM could be a potential therapeutic adjuvant agent for ischemia‒reperfusion injury in the kidney and several other organs.

Hibiscus sabdariffa Linn. Extract Increases the mRNA Expression of the Arcuate Nucleus Leptin Receptor and is Predicted in silico as an Anti-obesity Agent.

Leptin is predominant in regulating body weight by stimulating energy expenditure through its neuronal action in the brain. Moreover, it is projected to adipose tissue and induces adipocyte browning by activating the β3-adrenergic receptor (β3AR). However, the expression of leptin receptor (Lep-R) and β3AR in people with obesity is downregulated. We hypothesized that Hibiscus sabdariffa Linn. extract (HSE) would increase hypothalamus arcuate nucleus (ARC) Lep-R and white adipose tissue (WAT) β3AR mRNA expression in DIO rats. This study also analyzed the potency of H. sabdariffa bioactive compounds as activators of Lep-R and β3AR by an in-silico experiment. Twenty-four male Sprague-Dawley rats were divided into four groups: Control (standard food), DIO (high-fat diet), DIO-Hib200 (HFD+HSE 200 mg/kg BW), and DIO-Hib400 (HFD+HSE400 mg/kg BW). HSE was administered orally for five weeks, once a day. HSE administration significantly (p <0,05) increased the ARC Lep-R expression. The Lee index significantly decreased to the normal range (≤ 310) with p <0,001 for DIO-Hib200 and p <0,01 for DIO-Hib400. Among 39 bioactive compounds, 5-O-caffeoyl shikimic acid exhibited high free binding scores (-8,63) for Lep-R, and myricetin_3_arabinogalactoside had high free binding scores (-9,39) for β3AR. These binding predictions could activate Lep-R and β3AR. This study highlights that HSE could be a potential therapeutic target for obesity by increasing LepR mRNA and leptin sensitivity, enhancing energy expenditure, and reducing obesity.

Mathurameha ameliorates cardiovascular complications in high-fat diet/low-dose streptozotocin-induced type 2 diabetic rats: insights from histological and proteomic analysis.

Type 2 diabetes mellitus (T2DM) is a global health concern with increasing prevalence. Mathurameha, a Thai herbal formula, has shown promising glucose-lowering effects and positive impacts on biochemical profiles in diabetic rats. The present study investigated the protective effects of Mathurameha on cardiovascular complications in high-fat diet/streptozotocin (HFD/STZ)-induced type 2 diabetic rats using histological and proteomic analyses. Thirty-five male Sprague-Dawley rats were divided into seven groups: normal diet (ND), ND with aqueous extract (ND + AE450), ND with ethanolic extract (ND + EE200), diabetes (DM), DM with AE (DM + AE450), DM with EE (DM + EE200), and DM with metformin (DM + Met). Mathurameha, especially at 200mg/kg EE, significantly reduced adipocyte size, cardiac and vascular abnormalities, collagen deposition, and arterial wall thickness in DM rats. Proteomic analysis of rat aortas revealed 30 significantly altered proteins among the ND, DM, and DM + EE200 groups. These altered proteins are involved in various biological processes related to diabetes. Biochemical assays showed that Mathurameha reduced lipid peroxidation (MDA), increased antioxidant levels (GSH), and decreased the expression of inflammatory markers (ICAM1, TNF-α). In conclusion, Mathurameha exhibited significant protective effects against cardiovascular complications in HFD/STZ-induced type 2 diabetic rats through its antioxidant and anti-inflammatory properties.

Transcriptomic Profiling Reveals Differences in Slow-Twitch and Fast-Twitch Muscles of a Cigarette Smoke-Exposed Rat Model.

Cigarette smoking is known to affect muscle function and exercise capacity, including muscle fatigue resistance. Most studies showed diminished cross-sectional area and fibre type shifting in slow-twitch muscles such as the soleus, while effects on fast-twitch muscles were seldom reported and the differential responses between muscle types in response to exposureto cigarette smoke (CS) were largely unknown. This study aimed to elucidate the histomorphological, biochemical and transcriptomic changes induced by CS on both slow-twitch and fast-twitch muscles. Male Sprague-Dawley rats were randomly divided into two groups: sham air (SA) and CS. The rats were exposed to CS for 8 weeks using an exposure chamber system to mimic smoking conditions. Histomorphological analyses on muscle fibre type and cross-sectional area were determined in soleus and extensor digitorum longus (EDL). Transcriptomic profiles were investigated for identifying differentially expressed genes (DEGs) and potential mechanistic pathways involved. Inflammatory responses in terms of the macrophage population and the level of inflammatory cytokines were measured. Markers for muscle-specific proteolysis were also examined. Soleus muscle, but not in EDL, exhibited a significant increase in Type IIa fibres (SA: 9.0 ± 3.3%; CS: 19.8 ± 2.4%, p = 0.002) and decrease in Type I fibres (SA: 90.1 ± 3.6%; CS: 77.9 ± 3.3%, p = 0.003) after CS exposure. RNA sequencing revealed 165 identified DEGs in soleus including upregulation of 'Cd68', 'Ccl2' and 'Ucp2' as well as downregulation of 'Ucp3', etc. Pathways enrichment analysis revealed that the upregulated pathways in soleus were related to immune system and cellular response, while the downregulated pathways were related to oxidative metabolism. Only 10 DEGs were identified in EDL with less enriched pathways. The soleus also showed elevated pro-inflammatory cytokines, and the total macrophage marker CD68 was significantly higher in soleus of CS compared to the SA group (CD68+/no. of fibre: SA = 60.3 ± 39.3%; CS = 106.5 ± 27.2%, p = 0.0039), while the two groups in EDL muscle showed no significant difference. The expression of E3 ubiquitin ligase atrogin-1 associated with muscle degradation pathways was 1.63-fold higher in the soleus after CS, while no significant differences were observed in the EDL. The CS-induced inflammatory responses on soleus muscle are likely mediated via targeting mitochondrial-related signalling, resulting in mitochondrial dysfunction and impaired oxidative capacity. The presumably less active mitochondrial-related signalling in EDL renders it less susceptible to changes towards CS, accounting for differential impacts between muscle types.