Male Rat Model Research Articles

The Masquelet induced membrane technique with PRP-FG-nHA/PA66 scaffold can heal a rat large femoral bone defect

BackgroundMasquelet membrane induction technology is one of the treatment strategies for large bone defect (LBD). However, the angiogenesis ability of induced membrane decreases with time and autologous bone grafting is associated with donor site morbidity. This study investigates if the PRP-FG-nHA/PA66 scaffold can be used as a spacer instead of PMMA to improve the angiogenesis ability of induced membrane and reduce the amount of autologous bone graft.MethodsPlatelet rich plasma (PRP) was prepared and PRP-FG-nHA/PA66 scaffold was synthesized and observed. The sustained release of VEGFA and porosity of the scaffold were analyzed. We established a femur LBD model in male SD rats. 55 rats were randomly divided into four groups depending on the spacer filled in the defect area. “Defect only” group (n = 10), “PMMA” group (n = 15), “PRP-nHA/PA66” group (n = 15) and “PRP-FG-nHA/PA66” group (n = 15 ). At 6 weeks, the spacers were removed and the defects were grafted. The induced membrane and bone were collected and stained. The bone formation was detected by micro-CT and the callus union was scored on a three point system.ResultsThe PRP-FG-nHA/PA66 scaffold was porosity and could maintain a high concentration of VEGFA after 30 days of preparation. The induced membrane in PRP-FG-nHA/PA66 group was thinner than PMMA, but the vessel density was higher.The weight of autogenous bone grafted in PRP-FG-nHA/PA66 group was significantly smaller than that of PMMA group. In PRP-FG-nHA/PA66 group, the bone defect was morphologically repaired.ConclusionThe study showed that PRP-FG-nHA/PA66 scaffold can significantly reduce the amount of autologous bone graft, and can achieve similar bone defect repair effect as PMMA. Our findings provide some reference and theoretical support for the treatment of large segmental bone defects in humans.

Intrathecal gastrodin alleviates allodynia in a rat spinal nerve ligation model through NLRP3 inflammasome inhibition

BackgroundGastrodin (GAS), a main bioactive component of the herbal plant, Gastrodia elata Blume, has shown to have beneficial effects on neuroinflammatory diseases such as Alzheimer’s disease in animal studies and migraine in clinical studies. Inflammasome is a multimeric protein complex having a core of pattern recognition receptor and has been implicated in the development of neuroinflammatory diseases. Gastrodin has shown to modulate the activation of nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome. This study investigated the effects of GAS on the intensity of mechanical allodynia and associated changes in NLRP3 inflammasome expression at the spinal level using L5/6 spinal nerve ligation model (SNL) in rats.MethodsIntrathecal (IT) catheter implantation and SNL were used for drug administration and pain model in male Sprague-Dawley rats. The effect of gastrodin or MCC950 (NLRP3 inflammasome inhibitor) on mechanical allodynia was measured by von Frey test. Changes in NLRP3 inflammasome components and interleukin-1β (IL-1β) and cellular expression were examined in the spinal cord and dorsal root ganglion.ResultsThe expression of NLRP3 inflammasome components was found mostly in the neurons in the spinal cord and dorsal root ganglion. The protein and mRNA levels of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), caspase-1, and IL-1β were upregulated in SNL animals compared to Sham animals. IT administration of GAS significantly attenuated the expression of NLRP3 inflammasome and the intensity of SNL-induced mechanical allodynia. NLRP3 inflammasome inhibitor, MCC950, also attenuated the intensity of allodynia, but the effect is less strong and shorter than that of GAS.ConclusionsExpression of NLRP3 inflammasome and IL-1β is greatly increased and mostly found in the neurons at the spinal level in SNL model, and IT gastrodin exerts a significant anti-allodynic effect in SNL model partly through suppressing the expression of NLRP3 inflammasome.

Possible Protective Effect of Co-administration of Hydrogen Sulfide and Exosomes versus Hydrogen Sulfide Preconditioned Exosomes on Hepatic Ischemia Reperfusion Injury in Adult Male Rat Model: Biochemical, Histological and Immunohistochemical Study

Possible Protective Effect of Co-administration of Hydrogen Sulfide and Exosomes versus Hydrogen Sulfide Preconditioned Exosomes on Hepatic Ischemia Reperfusion Injury in Adult Male Rat Model: Biochemical, Histological and Immunohistochemical Study

Sodium arsenite impairs sperm quality via downregulating the ZMYND15 and ZMYND10.

Zinc finger MYND-type containing 15 (ZMYND15) has been documented to play important roles in spermatogenesis, and mutants contribute to recessive azoospermia, severe oligozoospermia, non-obstructive azoospermia, teratozoospermia, even male infertility. ZMYND10 is involved in sperm motility. Whether environmental pollutants impair male fertility via regulating the expression of ZMYND15 and ZMYND10 has not been studied. Arsenic exposure results in poor sperm quality and male infertility. In order to investigate whether arsenic-induced male reproductive toxicity is related to the expression of ZMYND15, ZMYND10 and their target genes, we established a male rat model of sodium arsenite exposure-induced reproductive injury, measured sperm quality, serum hormone levels, mRNA and protein expressions of intratesticular ZMYND15 and ZMYND10 as well as their target genes. The results showed that, in addition to the increased mRNA expression of Tnp1, sodium arsenite exposure reduced sperm quality, serum hormone levels, and mRNA and protein expression of intratesticular ZMYND15 and ZMYND10 and their target genes in male rats compared with the control group (p < .05). Therefore, our study first showed that the environmental pollutant arsenic impairs sperm quality in male rats by reducing the expression of ZMYND10 and ZMYND15 and their regulatory genes, which provides a possible diagnostic marker for environmental pollutants-induced male infertility.

Implication changes of serum adiponectin in chronic Moderate aerobic and resistant pattern of exercise in male albino rat model of Alzheimer

Implication changes of serum adiponectin in chronic Moderate aerobic and resistant pattern of exercise in male albino rat model of Alzheimer

Effect of intrahippocampal microinjection of VU0155041, a positive allosteric modulator of mGluR4, on long term potentiation in a valproic acid-induced autistic male rat model

The precise cause of autism spectrum disorder (ASD) is not fully understood. Despite the involvement of glutamatergic dysregulation in autism, the specific contribution of mGlu4 receptors to synaptic plasticity remains unclear. Using the positive allosteric modulator VU0155041, we aimed to restore long-term potentiation (LTP) in the perforant path-dentate gyrus (PP-DG) pathway in VPA-induced autistic rat model. High-frequency stimulation was applied to the PP-DG synapse to induce LTP, while the VU0155041 was administered into the DG. Unexpectedly, VU0155041 failed to alleviate the observed LTP reduction in VPA-exposed rats, further resulting in a significant decrease in population spike LTP. This unexpected outcome prompts discussion on the complex nature of mGlu4 receptor modulation, highlighting potential interference with physiological processes underlying synaptic plasticity.

Impact of various dietary lipids on amelioration of biomarkers linked to metabolic syndrome in both healthy and diabetic Wistar rats

BackgroundThe present study was designed to investigate the influence of different dietary lipids (sheep’s fat, olive oil, coconut oil, and corn oil) on specific biomarkers associated with metabolic syndrome in both healthy and diabetic rats.MethodsThe study designed for 45 days, utilized a male diabetic wistar rat (body weight, 180–220 g) model induced by streptozotocin (45 mg/kg bw). The rats were divided into two sections: five non-diabetic and five diabetic groups, each containing six rats. The first group in each section serving as the control, received a standard diet. Both non-diabetic or diabetic groups, were provided with a standard diet enriched with 15% sheep fat, 15% coconut oil, 15% olive oil, and 15% corn oil, respectively for a duration of 45 days.ResultsPost-supplementation, both healthy and diabetic control rats exhibited a higher food intake compared to rats supplemented with lipid diet; notably food intake was higher in diabetic control than healthy control. However, rats fed with coconut oil, olive oil and sheep fat showed weight gain at the end of the experiment, in both healthy and diabetic groups. Coconut oil supplementation significantly (p ≤ 0.05) increased HDL-C and total cholesterol level in diabetic groups compared to healthy group, it was confirmed by an increased PPAR-α and ABCA-1 protein level. Olive oil significantly decreased triglyceride, total cholesterol, and LDL-C levels in diabetic rats when compared to sheep fat or coconut oil. Corn oil significantly decreased fasting glucose, total cholesterol and LDL-C levels compared to all other groups. Corn and olive oil supplemented normal groups, found with significant increase in hepatic glucose-lipid oxidative metabolism associated protein, like FGF-21, MSH, ABCA-1, PPAR-γ and decreased lipogenesis proteins like, SREBP and PPAR-α levels. In contrast, sheep grease and coconut oil increased SREBP and PPAR-α expression in both normal and diabetic groups. Most notably, normal and diabetic groups pretreated with sheep grease resulted in increased inflammatory (MCP-1, IL-1β, TLR-4, TNF-α), and oxidative stress markers (LPO, GSH, GPx, SOD and CAT) linked with metabolic complications.ConclusionThe combination or alternative use of olive oil and corn oil in daily diet may play a significant role in preventing proinflammatory condition associated with insulin resistance and cardiovascular diseases.

Granulocyte- Macrophage Colony-Stimulating Factor Reverses Immunosuppression Acutely Following a Traumatic Brain Injury and Hemorrhage Polytrauma in a Juvenile Male Rat Model.

Traumatic brain injury (TBI) is a common cause of morbidity and mortality in children. We have previously shown that TBI with a concurrent extracranial injury reliably leads to post-injury suppression of the innate and adaptive immune systems. In patients with post-injury immune suppression, if immune function could be preserved, this might represent a therapeutic opportunity. As such, we examined, in an animal injury model, whether systemic administration of granulocyte macrophage colony-stimulating factor (GM-CSF) could reverse post-injury immune suppression and whether treatment was associated with neuroinflammation or functional deficit. Prepubescent male rats were injured using a controlled cortical impact model and then subjected to removal of 25% blood volume (TBI/H). Sham animals underwent surgery without injury induction, and the treatment groups were sham and injured animals treated with either saline vehicle or 50 μg/kg GM-CSF. GM-CSF was administered following injury and then daily until sacrifice at post-injury day (PID) 7. Immune function was measured by assessing tumor necrosis factor-α (TNF-α) levels in whole blood and spleen following ex vivo stimulation with pokeweed mitogen (PWM). Brain samples were assessed by multiplex enzyme-linked immunosorbent assay (ELISA) for cytokine levels and by immunohistochemistry for microglia and astrocyte proliferation. Neuronal cell count was examined using cresyl violet staining. Motor coordination was evaluated using the Rotarod performance test. Treatment with GM-CSF was associated with a significantly increased response to PWM in both whole blood and spleen. GM-CSF in injured animals did not lead to increases in levels of pro-inflammatory cytokines in brain samples but was associated with significant increases in counted astrocytes. Finally, while injured animals treated with saline showed a significant impairment on behavioral testing, injured animals treated with GM-CSF performed similarly to uninjured animals. GM-CSF treatment in animals with combined injury led to increased systemic immune cell response in whole blood and spleen in the acute phase following injury. Improved immune response was not associated with elevated pro-inflammatory cytokine levels in the brain or functional impairment.

Chronic kidney disease alters tryptophan metabolite concentrations in male and female Sprague Dawley rats

Kynurenine is the first stable metabolite of tryptophan degradation. An increased ratio of kynurenine (KYN) to tryptophan (TRP) has been implicated in many disease states including chronic kidney disease (CKD) in humans. We hypothesized that we would see a similar increase in KYN/TRP in a CKD model in male and female rats. We induced CKD with a 0.25% adenine diet for 15 weeks and then measured a variety of renal parameters. Serum and kidneys were collected at sacrifice. We found that GFR was better preserved in CKD female rats compared to males (0.232 ± 0.056 vs. 0.081 ± 0.019 ml/min/100g BW) but was decreased significantly compared to controls (0.739 ± 0.048 female, 0.635 ± 0.099 male). Urine volume was elevated significantly in CKD rats compared to controls (80.0 ± 6.9 ml/day male CKD, 72.5 ± 4.7 female CKD vs. 13.3 ± 1.1 male CTL and 22.0 ± 1.8 female CTL). However, male CKD rats consumed significantly more water than female CKD (104.1 ± 7.3 ml/day male vs. 81.0 ± 5.1 female), although water consumption was similar in controls in both sexes (30.9 ± 2.6 male and 30.1 ± 2.5 female). Weekly food consumption and body weight were similar between same sex groups. Both male and female rats showed increased KYN/TRP in CKD compared to controls (0.102 ± 0.010 in male and 0.105 ± 0.011 in female CKD vs. 0.049 ± 0.005 and 0.033 ± 0.002 CTL). Similarly, kynurenic acid was elevated significantly in both sexes in CKD (305.7 ± 76.7 nmol/L male and 669.2 ± 140.7 female) compared to controls (92.3 ± 17.7 and 118.1 ± 14.7) respectively. These data show that the adenine feeding model of CKD reproduces many of the characteristics of human disease including alterations in TRP metabolites. This model will allow study of TRP metabolites in CKD progression. This work was supported by Career Development Award IK2 BX004997 from the United States Department of Veteran Affairs, Biomedical Laboratory Research and Development Service. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

The effects of Anchusa azurea methanolic extract on burn wound healing: Histological, antioxidant, and anti-inflammatory evaluation

Anchusa azurea one of the medicinal plants that has been traditionally used for treat burn wounds. However, the traditional claim that A.azurea can hasten burn wound healing has not been supported by scientific studies. This experiment used a male Wistar rats model to investigate the activity of A. azurea aerial parts methanolic extract in burn wound healing. To determine their ability to help in healing burn wounds in rat models, the active components of the aerial parts of A. azurea were extracted with 80% methanol, then, 1% and 10% ointments were prepared from the extract, and applied topically. The LCMS chromatography of A. azurea plant extract showed different active ingredients, including phenolic compounds, flavonoids, fatty acids, and others. The plant extract's investigated as anti-inflammatory, antioxidant, and histological effects on the burn wound healing process. The results showed a significant (p-value < 0.025) rate of burn wound healing with 78.6% and 84.8% contraction, respectively using 1% and 10% (w/w) extract ointments after 12 days. These results were corroborated by histological observations such as collagen deposition, re-epithelialization, and repair of the remaining skin tissues without any sign of cutaneous toxicity. The plant extract showed significant (p-value < 0.025) antioxidant effect at the highest tested dose of 500 µg/mL, scavenging 89.78% of the DPPH with an IC50 of 213.6 µg/mL. These results confirmed by histological changes observations of collagen deposition, re-epithelialization, and reformation of remaining skin tissues without any signs of dermal toxicity. The plant extract exhibited significant (p-value < 0.025) level of antioxidant agents, by scavenging 89.78% of the DPPH at 500 µg/mL with IC50 of 213.6 µg/mL. Additionally, all pro-inflammatory cytokines examined, including IL-6 and IL-10, the results exhibited reduction in IL-6 level and increase IL-10 level. The aerial extract of the A. azurea plant revealed a wealth of several significant active ingredients, including phenolic compounds, flavonoids, fatty acids, and others, suggesting the potential for anti-inflammatory, burn wound-healing, and antioxidant medications. These findings can open an avenue to find new therapeutics for burn wounds healing, anti-inflammatory and antioxidant properties.

Social-Single Prolonged Stress affects contextual fear conditioning in male and female Wistar rats: Molecular insights in the amygdala

Stress exposure can lead to post-traumatic stress disorder (PTSD) in male and female rats. Social-Single Prolonged Stress (SPS) protocol has been considered a potential PTSD model. This study aimed to pharmacologically validate the Social-SPS as a PTSD model in male and female rats. Male and female Wistar rats (60-day-old) were exposed to Social-SPS protocol and treated with fluoxetine (10 mg/Kg) or saline solution intraperitoneally 24 h before euthanasia. Two cohorts of animals were used; for cohort 1, male and female rats were still undisturbed until day 7 post-Social-SPS exposure, underwent locomotor and conditioned fear behaviors, and were euthanized on day 9. Animals of cohort 2 were subjected to the same protocol but were re-exposed to contextual fear behavior on day 14. Results showed that fluoxetine-treated rats gained less body weight than control and Social-SPS in both sexes. Social-SPS effectively increased the freezing time in male and female rats on day eight but not on day fourteen. Fluoxetine blocked the increase of freezing in male and female rats on day 8. Different mechanisms for fear behavior were observed in males, such as Social-SPS increased levels of glucocorticoid receptors and Beclin-1 in the amygdala. Social-SPS was shown to increase the levels of NMDA2A, GluR-1, PSD-95, and CAMKII in the amygdala of female rats. No alterations were observed in the amygdala of rats on day fourteen. The study revealed that Social-SPS is a potential PTSD protocol applicable to both male and female rats.

From Zimbabwean Indigenous Knowledge: Scientific Substantiation of the Aphrodisiac Efficacy and Safety of Pittosporum viridiflorum in Male Rat Models

Introduction: Pittosporum viridiflorum, the multi habitat thriving plant species is widely believed to have been the source of sexual prowess for the polygamous kings and elites of the mighty medieval empire known as ‘Great Zimbabwe’. Despite the lack of systematic scientific validation, the macerated roots fractions continue to be the aphrodisiacs of choice among Zimbabweans.&#x0D; Aims: To scientifically validate the aphrodisiac claims using male rats’ sexual performance investigation protocols. To evaluate the toxicity profile and to identify the pharmacologically active metabolites present in the lyophilized hydro-ethanolic crude extracts.&#x0D; Methodology: Four concentrations of prepared Pittosporum viridiflorum root extract doses of 200, 400, 800 and 2000mg/kg as well as a commercial 5 mg/kg sildenafil citrate (standard) and distilled water (control) dosages were gavaged to male rats (n = 5 animals per group) for 21 days. The crude extract was subjected to screening protocols for various secondary metabolites of pharmacological relevance as well as acute oral toxicity profiling using OECD 425 TG. The sexual behaviour, mating parameters and hormonal changes in the male rats were evaluated accordingly.&#x0D; Observation and Results: Compared with the control, a significant increase in mating behaviour, mating performance and the serum hormonal levels were observed in test animals which showed a dose‑dependent bias. The phytoscreening evaluation confirmed the presence of saponins, phytosterols, flavonoids, di-terpenoids, tannins, and polyphenols. The Extract was toxicological safe with an LD50 above 2000mg/kg body weight.&#x0D; Conclusion: Pittosporum viridiflorum has excellent aphrodisiac activity on rats and is toxicologically safe for oral use. The abundant phytochemicals found are known to be pharmacologically active with regards to modulation of sexual hormones as well as sexual enhancement. It was further concluded that the traditional belief is valid, the plant can indeed be used as an alternative to modern medicines for various sexual dysfunctions and sexual performance enhancement.

Human neural stem cell secretome relieves endoplasmic reticulum stress-induced apoptosis and improves neuronal functions after traumatic brain injury in a rat model.

Neural stem cell secretome (NSC-S) plays an important role in neuroprotection and recovery. Studies have shown that endoplasmic reticulum stress (ER stress) is involved in the progression of traumatic brain injury (TBI) and is a crucial cause of secondary damage and neuronal death after brain injury. Whether NSC-S is engaged in ER stress and ER stress-mediated neuronal apoptosis post-TBI has not been investigated. In the study, the Feeney SD male rat model was established. The results showed that NSC-S treatment significantly improved the behavior of rats with TBI. In addition, NSC-S relieved ER stress in TBI rats and was observed by transmission electron microscopy and western blot. The specific mechanism was further elucidated that restoration was achieved by alleviating the PERK-eIF2α pathway and thus protecting neurons from apoptosis. Notably, the discovery of calumenin (CALU) in NSC-S by liquid chromatography-tandem mass spectrometry (LC-MS/MS/MS) may be related to the protective effect of NSC-S on ER stress in neurons. Also, the mechanism by which it functions may be related to ubiquitination. In summary, NSC-S improved prognosis and ER stress in TBI rats and might be a promising treatment for relieving TBI.

Vagotomy accelerates the onset of symptoms during early disease progression and worsens joint-level pathogenesis in a male rat model of chronic knee osteoarthritis

ObjectiveLow vagal tone is common in osteoarthritis (OA) comorbidities and results in greater peripheral inflammation. Characterizing vagal tone's role in OA pathogenesis may offer insights into OA's influences beyond the articular joint. We hypothesized that low vagal tone would accelerate onset of OA-related gait changes and worsen joint damage in a rat knee OA model. MethodsKnee OA was induced in male Sprague Dawley rats by transecting the medial collateral ligament and medial meniscus. Then, left cervical vagus nerve transection (VGX, n ​= ​9) or sham VGX (non-VGX, n ​= ​6) was performed. Gait and tactile sensitivity were assessed at baseline and across 12 weeks, with histology and systemic inflammation evaluated at endpoint. ResultsAt week 4, VGX animals showed limping gait characteristics through shifted stance times from their OA to non-OA limb (p ​= ​0.055; stance time imbalance ​= ​1.6 ​± ​1.6%) and shifted foot strike locations (p ​< ​0.001; spatial symmetry ​= ​48.4 ​± ​0.835%), while non-VGX animals walked with a balanced and symmetric gait. Also at week 4, while VGX animals had a mechanical sensitivity (50% withdrawal threshold) of 13.97 ​± ​7.70 compared to the non-VGX animal sensitivity of 29.74 ​± ​9.43, this difference was not statistically significant. Histologically, VGX animals showed thinner tibial cartilage and greater subchondral bone area than non-VGX animals (p ​= ​0.076; VGX: 0.80 ​± ​0.036 ​mm2; non-VGX: 0.736 ​± ​0.066 ​mm2). No group differences in systemic inflammation were observed at endpoint. ConclusionsVGX resulted in quicker onset of OA-related symptoms but remained unchanged at later timepoints. VGX also had thinner cartilage and abnormal bone remodeling than non-VGX. Overall, low vagal tone had mild effects on OA symptoms and joint remodeling, and not at the level seen in common OA comorbidities.

Wound healing activity of hydromethanolic Dioscorea bulbifera extract on male wistar rat excision wound models

IntroductionWound healing is a complex physiological process that involves a series of coordinated events that recover structural and functional tissue integrity. The desire to promote nature-based solutions has led to the screening of various plants and herbs for their wound healing potentials with results showing the enhancement of various aspects of the wound healing process. Dioscorea bulbifera possesses a wide range of applications in folk remedies. In traditional Chinese medicine, it is used in the treatment of mumps, goitre, sore throat, gastric cancer and carcinoma of the rectum alone or in combination with other plants. The present study evaluated the effect of hydromethanolic extract of Dioscorea bulbifera (HEDB) on wound size, percentage of wound contraction and tissue hydroxyproline in male Wistar rat excision wound models. MethodsTwenty-five (25) male Wistar rats (180–200 g) were used for the study. They were divided into five (5) groups comprising five (5) animals per group. A circular excision wound (1.5–2 cm) was experimentally induced in each animal following ketamine anaesthesia. Groups I and II served as negative and positive controls and were treated with topical administration of distilled water and petroleum jelly respectively. Groups III, IV and V served as the experimental groups and were treated with 200, 400 and 800 mg/kg of HEDB topically. The diameter of the wound was measured and the wound area and percentage of wound contraction were calculated. Tissue hydroxyproline was determined using tissue excised from the healed portion of the dorsal surface of the animals via coulometric standard procedures. ResultsData from the study indicates that animals in the experimental groups (III, IV and V) had an earlier wound closure compared to the control. Animals treated with 200 mg/kg HEDB (Group III) showed complete wound closure by day 17, whereas animals treated with 400 mg/kg (Group IV) and 800 mg/kg HEDB (Group V) groups achieved complete wound closure by the 18th and 20th day of the experiment respectively. Similarly, all the animals in the experimental groups had significantly increased percentage of wound contraction compared to negative control (P < 0.05). Tissue hydroxyproline was significantly raised amongst the animals treated with 200 and 800 mg/kgHEDB compared to the negative control (p < 0.05). DiscussionEvidence from the study has shown that HEDB possesses potent wound healing activity as the present study has demonstrated that it reduced wound area, and increased wound contraction and tissue hydroxyproline on experimentally induced excision wound male Wistar rat models. These findings provide scientific evidence that validates the traditional medicinal application of Dioscorea bulbifera in promoting wound healing.

Neurophysiological analysis of disadvantageous social inequity: Exploring emotional behavior changes and c-Fos expression in a male rat model

Humans and other animals exhibit aversive behavioral and emotional responses to unequal reward distributions compared with their conspecifics. Despite the significance of this phenomenon, experimental animal models designed to investigate social inequity aversion and delve into the underlying neurophysiological mechanisms are limited. In this study, we developed a rat model to determine the effects of socially equal or unequal reward and stress on emotional changes in male rats. During the training session, the rats were trained to escape when a sound cue was presented, and they were assigned to one of the following groups: all escaping rats [advantageous equity (AE)], freely moving rats alongside a restrained rat [advantageous inequity (AI)], all restrained rats [disadvantageous equity (DE)], and a rat restrained in the presence of freely moving companions [disadvantageous inequity (DI)]. During the test session, rats in the advantageous group (AE and AI) escaped after the cue sound (expected reward acquisition), whereas rats in the disadvantageous group (DE and DI) could not escape despite the cue being presented (expected reward deprivation). Emotional alteration induced by exposure to restraint stress under various social interaction circumstances was examined using an open field test. Notably, the DI group displayed reduced exploration of the center zone during the open field tests compared with the other groups, indicating heightened anxiety-like behaviors in response to reward inequity. Immunohistochemical analysis revealed increased c-Fos expression in the medial prefrontal and orbitofrontal cortices, coupled with reduced c-Fos expression in the striatum and nucleus accumbens under DI conditions, in contrast to the other experimental conditions. These findings provide compelling evidence that rats are particularly sensitive to reward inequity, shedding light on the neurophysiological basis for distinct cognitive processes that manifest when individuals are exposed to social equity and inequity situations.

A neutrophil elastase inhibitor, sivelestat, attenuates sepsis-induced acute kidney injury by inhibiting oxidative stress

BackgroundSivelestat, a selective inhibitor of neutrophil elastase (NE), can mitigate sepsis-related acute lung injury. However, the role of sivelestat in inhibiting oxidative stress and attenuating sepsis-related acute kidney injury (AKI) remains unclear. Here, we reported the effects of sivelestat against oxidative stress-induced AKI by suppressing the production of oxidative stress indicators. Materials and methodsA male Sprague-Dawley rat model of sepsis was established by cecal ligation and puncture (CLP). Sivelestat or normal saline was administered into jugular vein with a sustained-release drug delivery system. Indicators of inflammation and AKI, including white blood cells (WBC), neutrophils, lymphocytes, C-reactive proteins (CRP), procalcitonin (PCT), blood urea nitrogen (BUN), creatinine (Cr) and uric acid (UA), were assessed at 24 h post-sivelestat treatment. Indicators of liver injury, including direct bilirubin (DBIL), indirect bilirubin (IBIL), aspartate aminotransferase (AST) and alanine aminotransferase (ALT), were also assessed at 24 h post-sivelestat treatment. Indicators of oxidative stress, including superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-Px), were assessed at 12 h and 24 h post-sivelestat treatment. At 24 h post-sivelestat treatment, H&E staining of kidney and liver tissue was performed to observe pathological alterations. ResultsAt 24 h post normal saline or sivelestat (0.2 g/kg body weight) treatment, WBC, neutrophil, CRP, PCT, MDA, BUN, Cr, UA, AST, ALT, DBIL and IBIL were increased, while SOD and GSH-Px were decreased, in septic rats treated with normal saline compared with that in non-septic rats treated with normal saline (all p < 0.05). The changes of these indicators were reversed in septic rats treated with sivelestat compared with that in septic rats treated with normal saline (all p < 0.05). Similar results were found regarding the levels of oxidative stress indicators at 12 h post-sivelestat treatment. The degenerative histopathological changes in both kidney and liver tissues were ameliorated upon sivelestat treatment. ConclusionsSivelestat plays a protective role in sepsis-related AKI by inhibiting oxidative stress. Our study reveals a possible therapeutic potential of sivelestat for oxidative stress-induced AKI.

Effects of Synergistic Consuption of Aqueous Extract of Cyperus esculentus, Phoenix dactylifera and Cocos nucifera on Hematological Indices in Male Rat Model

Effects of Synergistic Consuption of Aqueous Extract of Cyperus esculentus, Phoenix dactylifera and Cocos nucifera on Hematological Indices in Male Rat Model

Contribution of pudendal nerve injury to stress urinary incontinence in a male rat model

Urinary incontinence is a common complication following radical prostatectomy, as the surgery disturbs critical anatomical structures. This study explored how pudendal nerve (PN) injury affects urinary continence in male rats. In an acute study, leak point pressure (LPP) and external urethral sphincter electromyography (EMG) were performed on six male rats with an intact urethra, the urethra exposed (UE), the PN exposed (NE), and after PN transection (PNT). In a chronic study, LPP and EMG were tested in 67 rats 4 days, 3 weeks, or 6 weeks after sham PN injury, PN crush (PNC), or PNT. Urethras were assessed histologically. Acute PNT caused a significant decrease in LPP and EMG amplitude and firing rate compared to other groups. PNC resulted in a significant reduction in LPP and EMG firing rate 4 days, 3 weeks, and 6 weeks later. EMG amplitude was also significantly reduced 4 days and 6 weeks after PNC. Neuromuscular junctions were less organized and less innervated after PNC or PNT at all timepoints compared to sham injured animals. Collagen infiltration was significantly increased after PNC and PNT compared to sham at all timepoints. This rat model could facilitate preclinical testing of neuroregenerative therapies for post-prostatectomy incontinence.

Targeted Delivery of Abaloparatide to Spinal Fusion Site Accelerates Fusion Process in Rats.

Spinal fusions are performed to treat congenital skeletal malformations, spondylosis, degenerative disk diseases, and other pathologies of the vertebrae that can be resolved by reducing motion between neighboring vertebrae. Unfortunately, up to 100,000 fusion procedures fail per year in the United States, suggesting that efforts to develop new approaches to improve spinal fusions are justified. We have explored whether the use of an osteotropic oligopeptide to target an attached bone anabolic agent to the fusion site might be exploited to both accelerate the mineralization process and improve the overall success rate of spinal fusions. The data presented below demonstrate that subcutaneous administration of a modified abaloparatide conjugated to 20 mer of D-glutamic acid not only localizes at the spinal fusion site but also outperforms the standard of care (topically applied BMP2) in both speed of mineralization (p < 0.05) and overall fusion success rate (p < 0.05) in a posterior lateral spinal fusion model in male and female rats, with no accompanying ectopic mineralization. Because the bone-localizing conjugate can be administered ad libitum post-surgery, and since the procedure appears to improve on standard of care, we conclude that administration of a bone-homing anabolic agent for improvement of spinal fusion surgeries warrants further exploration.