Type 2 vomeronasal receptor-A4 subfamily: Potential predator sensors in mice.

Sensory signals detected by olfactory sensory organs are critical regulators of animal behavior. An accessory olfactory organ, the vomeronasal organ, detects cues from other animals and plays a pivotal role in intra- and inter-species interactions in mice. However, how ethologically relevant cues control mouse behavior through approximately 350 vomeronasal sensory receptor proteins largely remains elusive. The type 2 vomeronasal receptor-A4 (V2R-A4) subfamily members have been repeatedly detected from vomeronasal sensory neurons responsive to predator cues, suggesting a potential role of this receptor subfamily as a sensor for predators. This review focuses on this intriguing subfamily, delving into its receptor functions and genetic characteristics.

Hearing loss in juvenile rats leads to excessive play fighting and hyperactivity, mild cognitive deficits and altered neuronal activity in the prefrontal cortex.

Background: In children, hearing loss has been associated with hyperactivity, disturbed social interaction, and risk of cognitive disturbances. Mechanistic explanations of these relations sometimes involve language. To investigate the effect of hearing loss on behavioral deficits in the absence of language, we tested the impact of hearing loss in juvenile rats on motor, social, and cognitive behavior and on physiology of prefrontal cortex. Methods: Hearing loss was induced in juvenile (postnatal day 14) male Sprague-Dawley rats by intracochlear injection of neomycin under general anesthesia. Sham-operated and non-operated hearing rats served as controls. One week after surgery auditory brainstem response (ABR) measurements verified hearing loss or intact hearing in sham-operated and non-operated controls. All rats were then tested for locomotor activity (open field), coordination (Rotarod), and for social interaction during development in weeks 1, 2, 4, 8, 16, and 24 after surgery. From week 8 on, rats were trained and tested for spatial learning and memory (4-arm baited 8-arm radial maze test). In a final setting, neuronal activity was recorded in the medial prefrontal cortex (mPFC). Results: In the open field deafened rats moved faster and covered more distance than sham-operated and non-operated controls from week 8 on (both p < 0.05). Deafened rats showed significantly more play fighting during development (p < 0.05), whereas other aspects of social interaction, such as following, were not affected. Learning of the radial maze test was not impaired in deafened rats (p > 0.05), but rats used less next-arm entries than other groups indicating impaired concept learning (p < 0.05). In the mPFC neuronal firing rate was reduced and enhanced irregular firing was observed. Moreover, oscillatory activity was altered, both within the mPFC and in coherence of mPFC with the somatosensory cortex (p < 0.05). Conclusions: Hearing loss in juvenile rats leads to hyperactive behavior and pronounced play-fighting during development, suggesting a causal relationship between hearing loss and cognitive development. Altered neuronal activities in the mPFC after hearing loss support such effects on neuronal networks outside the central auditory system. This animal model provides evidence of developmental consequences of juvenile hearing loss on prefrontal cortex in absence of language as potential confounding factor.

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 extra-cranial 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 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 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 given following injury and then daily until sacrifice at post-injury day 7. Immune function was measured by assessing TNF-α levels in whole blood and spleen following ex-vivo stimulation with poke weed mitogen (PWM). Brain samples were assessed by multiplex 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 similar 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 brain or functional impairment.

Alleviating sepsis: Revealing the protective role of costunolide in a cecal ligation and puncture rat model.

Objectives: Sepsis poses a significant threat to human life, rendering it a burdensome medical disease. Despite significant advancements, the current state of medical science still lacks a viable and efficacious cure. Costunolide (COST) is a multifaceted sesquiterpene lactone that exhibits a range of actions, including anti-inflammatory and antioxidant properties. We investigated the potential impacts of COST on a rat sepsis model caused by cecal ligation and puncture (CLP). Materials and Methods: We created an experimental rat model with the following groups: SHAM, CLP, CLP+low dose COST, and CLP+high dose COST. Blood, kidney, and lung samples were collected. Inflammatory mediators such as interleukin-1beta (IL-1ß), IL-6, tumor necrosis factor-alpha (TNF- α), and nuclear factor kappa-B (NF-κB) were investigated. In addition, we assessed oxidative stress by measuring 8-Hydroxydeoxyguanosine (8-OHdG) immunopositivity, MDA levels, glutathione (GSH), and superoxide dismutase (SOD) activity. Histopathological and immunohistochemical examinations backed up our findings. Results: Compared to the CLP group, the COST group showed a reduction in inflammatory and oxidative stress indicators. The expression of inflammatory mediators was suppressed by COST, and histological examinations revealed improvements in kidney and lung tissues in the treatment groups. Conclusion: Our study highlights the preventive effects of COST against CLP-induced sepsis-related injury. Considering its beneficial effects against many diseases, COST is worthy as to be evaluated against sepsis.

Concomitant use of Pre-emptive analgesia with Local and General Anesthesia in Rat Uterine Surgical Pain Model.

Preemptive analgesia is used for postoperative pain management, providing pain relief with few adverse effects. In this study, the effect of a preemptive regime on rat behavior and c-fos expression in the spinal cord of the uterine surgical pain model was evaluated. METHOD: It was a lab-based experimental study in which sixty female Sprague-Dawley rats; eight to ten weeks old, weighing 150-300 gm were used. The rats were divided into three main groups: i) Control group (CG), ii) superficial pain group (SG) (with skin incision only), iii) deep pain group (with skin and uterine incisions). Each group was further divided into three subgroups based on the type of preemptive analgesia administered i.e., "tramadol, buprenorphine, and saline subgroups." Pain behavior was evaluated using the "Rat Grimace Scale" (RGS) at 2, 4, 6, 9 and 24 hours post-surgery. Additionally, c-fos immunohistochemistry was performed on sections from the spinal dorsal horn (T12-L2), and its expression was evaluated using optical density and mean cell count two hours postoperatively. RESULTS: Significant reduction in the RGS was noted in both the superficial and deep pain groups within the tramadol and buprenorphine subgroups when compared to the saline subgroup (p≤0.05). There was a significant decrease in c-fos expression both in terms of number of c-fos positive cells and the optical density across the superficial laminae and lamina X of the spinal dorsal horn in both SD and DG (p≤0.05). In contrast, the saline group exhibited c-fos expression primarily in laminae I-II and III-IV for both superficial and deep pain groups and lamina X in the deep pain group only (p≤0.05). CONCLUSION: A preemptive regimen results in significant suppression of both superficial and deep components of pain transmission. These findings provide compelling evidence of the analgesic efficacy of preemptive treatment in alleviating pain response associated with uterine surgery.

Genotyping of Leptospira spp. in wild rats leads to first time detection of L. kirshneri serovar Mozdok in Serbia.

Introduction: This study aimed to investigate the prevalence and molecular characterization of Leptospira species in Belgrade, Serbia, an area where this disease is underexplored. Specifically, the study sought to employ molecular and multilocus sequence typing analyses to fill the gap in understanding the diversity and distribution of Leptospira species within the region. Methods: A comprehensive molecular analysis was conducted on kidney samples obtained from Norway rats (Rattus norvegicus) in the urban environment. The study utilized molecular diagnostic techniques including real-time PCR targeting the lipL32 gene and performing sequence-based typing schemes utilizing adk, icdA, lipL32, lipL41, rrs2, and secY genes. These methodologies were applied to ascertain the presence and characterize different Leptospira species and serovars, respectively. Results: The findings revealed the presence of two Leptospira species and three separate serovars in the Belgrade area. This study identified the presence of L. kirschneri serovar Mozdok in Serbia for the first time, a significant discovery previously undocumented in the region. This pioneering investigation sheds light on the molecular diversity and prevalence of Leptospira species in Serbia. Discussion: The study underscores the importance of employing molecular typing methods to gain insights into the epidemiology and characterization of Leptospira species. These findings significantly contribute to both local and global perspectives on leptospirosis epidemiology, providing vital insights for the development of effective control strategies and interventions. Summary: In our recent study, we explored the presence and performed molecular typing of the Leptospira species, the bacteria responsible for leptospirosis, in wild rats in Serbia. This was the first time such a study was conducted in the region. Leptospirosis is a serious disease that affects both animals and humans, often transmitted through contact with water contaminated by infected animals. Our focus was on understanding which types of Leptospira were present in these animals. Excitingly, we discovered a particular strain of Leptospira, known as L. kirshneri serovar Mozdok, for the first time in Serbia. This finding is significant because it sheds light on the presence and spread of different Leptospira serovars in Serbia. It also raises awareness about the potential health risks associated with this serovar, which was previously unknown in the area. Our work fits into a broader context of disease surveillance and public health. By identifying the types of Leptospira present in a specific region, we can better understand the risks to public health and take steps to prevent and control the spread of leptospirosis. This discovery is not just important for scientists studying infectious diseases; it has real implications for public health officials, veterinarians, and anyone concerned with preventing and treating leptospirosis. Our findings highlight the need for ongoing monitoring of Leptospira in wildlife and synanthropic fauna, to protect both animal and human health.

Local application of zoledronate inhibits early bone resorption and promotes bone formation.

Nonunion resulting from early bone resorption is common after bone transplantation surgery. In these patients, instability or osteoporosis causes hyperactive catabolism relative to anabolism, leading to graft resorption instead of fusion. Systemic zoledronate administration inhibits osteoclastogenesis and is widely used to prevent osteoporosis; however, evidence on local zoledronate application is controversial due to osteoblast cytotoxicity, uncontrolled dosing regimens, and local release methods. We investigated the effects of zolendronate on osteoclastogenesis and osteogenesis and explored the corresponding signaling pathways. In vitro cytotoxicity and differentiation of MC3T3E1 cells, rat bone marrow stromal cells (BMSCs) and preosteoclasts (RAW264.7 cells) were evaluated with different zolendronate concentrations. In vivo bone regeneration ability was tested by transplanting different concentrations of zolendronate with ß-tricalcium phosphate (TCP) bone substitute into rat femoral critical-sized bone defects. In vitro, zolendronate concentrations below 2.5 × 10-7 M did not compromise viability in the three cell lines and did not promote osteogenic differentiation in MC3T3E1 cells and BMSCs. In RAW264.7 cells, zoledronate inhibited extracellular regulated protein kinases and c-Jun n-terminal kinase signaling, downregulating c-Fos and NFATc1 expression, with reduced expression of fusion-related dendritic cell­specific transmembrane protein and osteoclast-specific Ctsk and tartrate-resistant acid phosphatase (. In vivo, histological staining revealed increased osteoid formation and neovascularization and reduced fibrotic tissue with 500 µM and 2000 µM zolendronate. More osteoclasts were found in the normal saline group after 6 weeks, and sequential osteoclast formation occurred after zoledronate treatment, indicating inhibition of bone resorption during early callus formation without inhibition of late-stage bone remodeling. In vivo, soaking ß-TCP artificial bone with 500 µM or 2000 µM zoledronate is a promising approach for bone regeneration, with potential applications in bone transplantation.

Optimal Intermittent Administration Interval of Abaloparatide for Bone Morphogenetic Protein-Induced Bone Formation in a Rat Spinal Fusion Model.

Both bone morphogenetic protein 2 (BMP-2) and abaloparatide are used to promote bone formation. However, there is no consensus about their optimal administration. We investigated the optimal administration theory for the pairing of BMP-2 and abaloparatide in a rat spinal fusion model. Group I was only implanted in carriers and saline. Carriers with 3 µg of recombinant human BMP-2 (rhBMP-2) were implanted in other groups. Abaloparatide injections were administered three times a week for group III (for a total amount of 120 µg/kg in a week) and six times a week for group IV (for a total amount of 120 µg/kg in a week) after surgery. They were euthanized 8 weeks after the surgery, and we explanted their spines at that time. We assessed them using manual palpation tests, radiography, high-resolution micro-computed tomography (micro-CT), and histological analysis. We also analyzed serum bone metabolism markers. The fusion rate in Groups III and IV was higher than in Group I, referring to the manual palpation tests. Groups III and IV recorded greater radiographic scores than those in Groups I and II, too. Micro-CT analysis showed that Tbs. Sp in Groups III and IV was significantly lower than in Group I. Tb. N in Group IV was significantly higher than in Group I. Serum marker analysis showed that bone formation markers were higher in Groups III and IV than in Group I. On the other hand, bone resorption markers were lower in Group IV than in Group I. A histological analysis showed enhanced trabecular bone osteogenesis in Group IV. Frequent administration of abaloparatide may be suitable for the thickening of trabecular bone structure and the enhancement of osteogenesis in a rat spinal fusion model using BMP-2 in insufficient doses.

Unveiling Drivers of Retinal Degeneration in RCS Rats: Functional, Morphological, and Molecular Insights.

Retinal degenerative diseases, including age-related macular degeneration and retinitis pigmentosa, significantly contribute to adult blindness. The Royal College of Surgeons (RCS) rat is a well-established disease model for studying these dystrophies; however, molecular investigations remain limited. We conducted a comprehensive analysis of retinal degeneration in RCS rats, including an immunodeficient RCS (iRCS) sub-strain, using ocular coherence tomography, electroretinography, histology, and molecular dissection using transcriptomics and immunofluorescence. No significant differences in retinal degeneration progression were observed between the iRCS and immunocompetent RCS rats, suggesting a minimal role of adaptive immune responses in disease. Transcriptomic alterations were primarily in inflammatory signaling pathways, characterized by the strong upregulation of Tnfa, an inflammatory signaling molecule, and Nox1, a contributor to reactive oxygen species (ROS) generation. Additionally, a notable decrease in Alox15 expression was observed, pointing to a possible reduction in anti-inflammatory and pro-resolving lipid mediators. These findings were corroborated by immunostaining, which demonstrated increased photoreceptor lipid peroxidation (4HNE) and photoreceptor citrullination (CitH3) during retinal degeneration. Our work enhances the understanding of molecular changes associated with retinal degeneration in RCS rats and offers potential therapeutic targets within inflammatory and oxidative stress pathways for confirmatory research and development.

Unified Methodology for the Primary Preclinical In Vivo Screening of New Anticoagulant Pharmaceutical Agents from Hematophagous Organisms.

The development of novel anticoagulants requires a comprehensive investigational approach that is capable of characterizing different aspects of antithrombotic activity. The necessary experiments include both in vitro assays and studies on animal models. The required in vivo approaches include the assessment of pharmacokinetic and pharmacodynamic profiles and studies of hemorrhagic and antithrombotic effects. Comparison of anticoagulants with different mechanisms of action and administration types requires unification of the experiment scheme and its adaptation to existing laboratory conditions. The rodent thrombosis models in combination with the assessment of hemostasis parameters and hematological analysis are the classic methods for conducting preclinical studies. We report an approach for the comparative study of the activity of different anticoagulants in vivo, including the investigation of pharmacodynamics and the assessment of hemorrhagic effects (tail-cut bleeding model) and pathological thrombus formation (inferior vena cava stenosis model of venous thrombosis). The reproducibility and uniformity of our set of experiments were illustrated on unfractionated heparin and dabigatran etexilate (the most common pharmaceuticals in antithrombic therapy) as comparator drugs and an experimental drug variegin from the tick Amblyomma variegatum. Variegin is notorious since it is a potential analogue of bivalirudin (Angiomax, Novartis AG, Basel, Switzerland), which is now being actively introduced into antithrombotic therapy.

The effect of calpain inhibitor-I on copper oxide nanoparticle-induced damage and cerebral ischemia-reperfusion in a rat model.

This study aimed to investigate the effects of the calpain inhibitor N-Acetyl-Leu-Leu-norleucinal (ALLN) on neuroapoptotic cell damage caused by Copper Oxide Nanoparticles (CuO-NP) and exacerbation of damage through brain ischemia/reperfusion (I/R) in a rat model. Male Wistar Albino rats (n=80) were divided into eight groups: Control, I/R, CuO-NP, CuO-NP+I/R, I/R+ALLN, CuO-NP+ALLN, CuO-NP+I/R+ALLN, and DMSO. Biochemical markers (MBP, S100B, NEFL, NSE, BCL-2, Cyt-C, Calpain, TNF-α, Caspase-3, MDA, and CAT) were measured in serum and brain tissue samples. Histological examinations (H&E staining), DNA fragmentation analysis (TUNEL) were performed, along with Caspase-3 assessment. The ALLN-treated groups exhibited significant improvements in biochemical markers and a remarkable reduction in apoptosis compared to the damaged groups (CuO-NP and I/R). H&E and Caspase-3 staining revealed damage-related morphological changes and reduced apoptosis in the ALLN-treated group. However, no differences were observed among the groups with TUNEL staining. The findings suggest that ALLN, as a calpain inhibitor, has potential implications for anti-apoptotic treatment, specifically in mitigating neuroapoptotic cell damage caused by CuO-NP and I/R.

Development of a wound epithelialization healing model: reducing the impact of contraction healing on the wound surface.

Animal experiments are important in trauma-related studies because they simulate in vivo effects. Rodents are a good choice for preparing trauma models; however, contractile healing in rodents results in a healing pattern that differs considerably from that in humans. Therefore, this study developed a new rodent model that avoids contractile healing of the skin around the wound using an anti-contraction ring, and the skin in the wound's center remains intact and acts as a source for epithelialized diffusion healing. Cell proliferation, migration, revascularization, and collagen secretion did not differ between the novel and conventional full-skin defect trauma models. However, the healing rate at various stages significantly differed between the two groups owing to differences in the healing patterns. And without effective treatment, the experimental group cannot heal. The stabilities of the novel and conventional methods were good regardless of operator or batch. In summary, this new animal trauma model provides a stable experimental environment similar to that in humans, which may promote trauma-related research.

Machine Learning for Prediction of Tuberculosis Detection: Case Study of Trained African Giant Pouched Rats.

BACKGROUND: Technological advancement has led to the growth and rapid increase of tuberculosis (TB) medical data generated from different health care areas, including diagnosis. Prioritizing better adoption and acceptance of innovative diagnostic technology to reduce the spread of TB significantly benefits developing countries. Trained TB-detection rats are used in Tanzania and Ethiopia for operational research to complement other TB diagnostic tools. This technology has increased new TB case detection owing to its speed, cost-effectiveness, and sensitivity. OBJECTIVE: During the TB detection process, rats produce vast amounts of data, providing an opportunity to identify interesting patterns that influence TB detection performance. This study aimed to develop models that predict if the rat will hit (indicate the presence of TB within) the sample or not using machine learning (ML) techniques. The goal was to improve the diagnostic accuracy and performance of TB detection involving rats. METHODS: APOPO (Anti-Persoonsmijnen Ontmijnende Product Ontwikkeling) Center in Morogoro provided data for this study from 2012 to 2019, and 366,441 observations were used to build predictive models using ML techniques, including decision tree, random forest, naïve Bayes, support vector machine, and k-nearest neighbor, by incorporating a variety of variables, such as the diagnostic results from partner health clinics using methods endorsed by the World Health Organization (WHO). RESULTS: The support vector machine technique yielded the highest accuracy of 83.39% for prediction compared to other ML techniques used. Furthermore, this study found that the inclusion of variables related to whether the sample contained TB or not increased the performance accuracy of the predictive model. CONCLUSIONS: The inclusion of variables related to the diagnostic results of TB samples may improve the detection performance of the trained rats. The study results may be of importance to TB-detection rat trainers and TB decision-makers as the results may prompt them to take action to maintain the usefulness of the technology and increase the TB detection performance of trained rats.

Subchronic toxicity study of indium-tin oxide nanoparticles following an intratracheal administration into the lungs of rats.

OBJECTIVES: We aimed to analyze the subchronic toxicity and tissue distribution of indium after the intratracheal administration of indium-tin oxide nanoparticles (ITO NPs) to the lungs of rats. METHODS: Male Wistar rats were administered a single intratracheal dose of 10 or 20 mg In/kg body weight (BW) of ITO NPs. The control rats received only an intratracheal dose of distilled water. A subset of rats was periodically euthanized throughout the study from 1 to 20 weeks after administration. Indium concentrations in the serum, lungs, mediastinal lymph nodes, kidneys, liver, and spleen as well as pathological changes in the lungs and kidneys were determined. Additionally, the distribution of ionic indium and indium NPs in the kidneys was analyzed using laser ablation-inductively coupled plasma mass spectrometry. RESULTS: Indium concentrations in the lungs of the two ITO NP groups gradually decreased over the 20-week observation period. Conversely, the indium concentrations in the mediastinal lymph nodes of the two ITO groups increased and were several hundred times higher than those in the kidneys, spleen, and liver. Pulmonary and renal toxicities were observed histopathologically in both the ITO groups. Both indium NPs and ionic indium were detected in the kidneys and their distributions were similar to the strong indium signals detected at the sites of inflammatory cell infiltration and tubular epithelial cells. CONCLUSIONS: Our results demonstrate that intratracheal administration of 10 or 20 mg In/kg body weight of ITO NPs in male rats produces pulmonary and renal toxicities.

[Effects and mechanisms of negative air ions on blood pressure, oxidative stress and inflammation levels in SHR rats].

OBJECTIVE: To investigate the effects and possible mechanisms of negative air ions(NAIs) on blood pressure, oxidative stress, and inflammatory status in spontaneous hypertension rats(SHR). METHODS: A total of 60 SHR(half male and half female) were randomly divided into one-month and three-month groups, 30 rats per groups, based on the duration of the intervention. Each group was further randomized into three groups based on the daily intervention time: SHR control group, 2 h NAIs-SHR group, and 6 h NAIs-SHR group, 10 rats per groups. In addition, 20 Wistar Kyoto(WKY)(half male and half female), were randomized into one-month WKY group and three-month WKY group, 10 rats per groups, based on the intervention time. The 2 h NAIs-SHR group and 6 h NAIs-SHR group were exposed to an environment with NAIs concentrations of 4.5×10~4-5×10~4 cm~3 per day for 2 h and 6 h. The WKY group and SHR group were exposed to normal air on a daily basis. Blood pressure of rats in each group was measured every three days, while weight was measured once a week. After sacrificing the rats in the first month and the third month of rearing, wet weight of the organs was weighed. The enzyme linked immunosorbent assay(ELISA) was used to detect 8-hydroxylated deoxyguanosine(8-OHdG), interleukin-6(IL-6), interleukin-8(IL-8), tumor necrosis factor-α(TNF-α), nitric oxide(NO) and endothelin-1(ET-1) levels. Reactive oxygen species(ROS) detection kit was used to detect ROS level. Malondialdehyde(MDA) and superoxide dismutase(SOD), glutathione(GSH) and glutathione disulfide(GSSG) were measured by colorimetric analysis. HE staining was conducted to observe the histopathological morphological changes of the thoracic aorta in each group, and Western blot was conducted to detect the thoracic aortap38 mitogen-activated protein kinase(p38 MAPK), extracellular signal-regulated kinases(ERK), c-Jun n-terminal kinase(JNK), c-fos proteins, c-jun proteins and their phosphorylated proteins level. RESULTS: The weight of WKY male mice in the same week age group was higher than that of SHR control group, and there was no significant difference in the weight between the other groups. The coefficient of heart in SHR control group(4.66±0.48) was higher than that in WKY group(3.73±0.15)(P<0.05), while there were no significant differences in the coefficients of brain, kidney, liver and spleen among the groups. Blood pressure in WKY group at the same age was lower than that in SHR group, and blood pressure in SHR control group at 2-5 and 8-11 weeks was higher than that in 2 h NAIs-SHR and 6 h NAIs-SHR groups(P<0.05). HE staining showed that the internal, middle and external membranes of thoracic aorta in 2 h NAIs-SHR group and 6 h NAIs-SHR group were improved to varying degrees compared with those in SHR control group, including disordered internal membrane structure, thickened middle membrane and broken external membrane. In terms of oxidative stress levels, compared with the SHR control group, the ROS(0.66%±0.17%, 0.49%±0.32%) and 8-OHdG((48.29±8.00) ng/mL, (33.13±14.67)ng/mL) levels were lower in the 6 h NAIs-SHR group(P<0.05), while the GSH/GSSG ratio was higher in the one-month 6 h NAIs-SHR group(10.08±4.93). Compared with the 2 h NAIs-SHR group, the ROS level(0.99%±0.19%) was lower in the 6 h NAIs-SHR group(P<0.05). In terms of inflammatory factor levels, compared with the SHR control group, the IL-8 levels((160.44±56.54) ng/L, (145.77±38.39) ng/L) were lower in the 6 h NAIs-SHR group(P<0.05), while the ET-1 level((249.55±16.98) ng/L) was higher in the one-month WKY group. There was no significant difference in NO levels among the groups. The relative expression of p-p38 protein in the thoracic aorta of rats in the one-month SHR control group was lower than that in the WKY group(P<0.05). The relative expression of p-p38 and p-c-fos proteins in the thoracic aorta of rats at three-months was higher in the SHR control group than in the 2 h NAIs-SHR and 6 h NAIs-SHR groups(P<0.05). CONCLUSION: The intervention of NAIs at a concentration of 4.5×10~4-5×10~4/cm~3 may regulate the partial oxidation and inflammatory state of SHR rats through the ROS/MAPK/AP1 signaling pathway, thereby reducing their blood pressure level.

Glycerol Trinitrate Acts Downstream of Calcitonin Gene-Related Peptide in Trigeminal Nociception-Evidence from Rodent Experiments with Anti-CGRP Antibody Fremanezumab.

Calcitonin gene-related peptide (CGRP) and nitric oxide (NO) have been recognized as important mediators in migraine but their mechanisms of action and interaction have not been fully elucidated. Monoclonal anti-CGRP antibodies like fremanezumab are successful preventives of frequent migraine and can be used to study CGRP actions in preclinical experiments. Fremanezumab (30 mg/kg) or an isotype control monoclonal antibody was subcutaneously injected to Wistar rats of both sexes. One to several days later, glyceroltrinitrate (GTN, 5 mg/kg) mimicking nitric oxide (NO) was intraperitoneally injected, either once or for three consecutive days. The trigeminal ganglia were removed to determine the concentration of CGRP using an enzyme-linked immunosorbent assay (ELISA). In one series of experiments, the animals were trained to reach an attractive sugar solution, the access to which could be limited by mechanical or thermal barriers. Using a semi-automated registration system, the frequency of approaches to the source, the residence time at the source, and the consumed solution were registered. The results were compared with previous data of rats not treated with GTN. The CGRP concentration in the trigeminal ganglia was generally higher in male rats and tended to be increased in animals treated once with GTN, whereas the CGRP concentration decreased after repetitive GTN treatment. No significant difference in CGRP concentration was observed between animals having received fremanezumab or the control antibody. Animals treated with GTN generally spent less time at the source and consumed less sugar solution. Without barriers, there was no significant difference between animals having received fremanezumab or the control antibody. Under mechanical barrier conditions, all behavioral parameters tended to be reduced but animals that had received fremanezumab tended to be more active, partly compensating for the depressive effect of GTN. In conclusion, GTN treatment seems to increase the production of CGRP in the trigeminal ganglion independently of the antibodies applied, but repetitive GTN administration may deplete CGRP stores. GTN treatment generally tends to suppress the animals' activity and increase facial sensitivity, which is partly compensated by fremanezumab through reduced CGRP signaling. If CGRP and NO signaling share the same pathway in sensitizing trigeminal afferents, GTN and NO may act downstream of CGRP to increase facial sensitivity.

Circumlimbal suture and laser burns: Comparison between two different chronic glaucoma models. / çŽ¯è§’è†œç¼˜ç¼åˆä¸Žæ¿€å ‰å ‰å‡æ¨¡åž‹ï¼šä¸¤ç§æ ¢æ€§é«˜çœ¼åŽ‹æ¨¡åž‹çš„æ¯”è¾ƒï¼ˆè‹±æ–‡ï¼‰.

OBJECTIVES: Glaucoma is a multifactorial optic neuropathy with a high rate of irreversible visual loss, and its pathogenesis is complex and still unclear. Elevated intraocular pressure (IOP) is well recognized as the sole modifiable risk factor for the development of glaucoma in the majority of cases. This study aims to compare 2 different methods of inducing chronic ocular hypertension by circumlimbal suture or by laser burns in degree and lasting time of the IOP, different status of the retina and retinal ganglion cells (RGCs), and changes of the microstructure of neurons. METHODS: The chronic ocular hypertension models were induced by 2 different ways. One kind of the models was built by unilateral circumlimbal suture (10/0) implantation (suture group), another kind of model was built by laser burns at trabecular meshwork and episcleral veins (laser group). The untreated contralateral eye served as the control group. Changes in IOP were observed and regularly monitored in the 2 groups of rats. HE staining was applied to observe the retinal and optic nerve pathology. Transmission electron microscope (TEM) was used to observe the mitochondrial morphology. RGCs were specifically labeled with Brn3b antibody and counted. The expression of caspase-3 was detected by Western blotting to clarify the apoptosis of RGCs. RESULTS: Compared with the control group, IOP were significantly increased in the suture group and the laser group (both P<0.05). The suture group induced a 1.5-fold elevation of IOP, and sustained for 8 weeks. The laser group induced a 2-fold elevation of IOP for 12 weeks. Both methods could cause RGCs loss (both P<0.05), which were verified by pathology and immune staining of Brn3b. The expressions of caspase-3 were also increased (both P<0.05). The mitochondrial morphology became more fragment, which changed from long shape to round and small one under TEM in 2 models. For comparison, the pathology changes of retinal structure in suture group were not obviously than those in the laser group. CONCLUSIONS: Circumlimbal suture can build an effective model of chronic elevated IOP and induce glaucomatous pathologic changes similar to those in the laser photocoagulation, but the pathologic changes are milder than those in laser photocoagulation. Compare with translimbal laser photocoagulation, equipment and skill demand for circumlimbal suture is less.

Enhancing fear extinction.

Gradually reducing a source of fear during extinction treatments may weaken negative memories in the long term.

[Effect and mechanism of aqueous extract of Strychni Semen on bone destruction in rats with type â ¡ collagen-induced rheumatoid arthritis].

To investigate the mechanism of action of aqueous extract of Strychni Semen(SA) on bone destruction in rats with type Ⅱ collagen-induced arthritis(CIA), the SD rats were randomly divided into normal group, model group, low, medium, and high dose(2.85, 5.70, and 11.40 mg·kg~(-1)) groups of SA, and methotrexate group. Except for the normal group, the CIA model was prepared for the other groups. After the second immunization, different doses of SA were given to the low, medium, and high dose groups of SA once a day, and the methotrexate group was given once every three days. 0.3% sodium hydroxymethylcellulose(CMC-Na) was given once a day to the normal and model groups for 28 d. The clinical score of arthritis was evaluated every three days. Micro computed tomography(Micro-CT) method was used to evaluate the degree of bone destruction. Histopathological changes in the joint tissue and the number of osteoclasts in CIA rats were evaluated by hematoxylin-eosin(HE) staining and tartrate-resistant acid phosphatase(TRAP) staining. The expression of interleukin-1ß(IL-1ß) in the joint tissue of rats was detected by immunohistochemistry. Western blot was used to detect key protein expression in mitogen-activated protein kinase(MAPK) and phosphatidylinositol 3-kinase/protein kinase B(PI3K/Akt) signaling pathways in the joint tissue of rats. The results showed that different doses of SA were able to improve the red and swollen inflammatory joint and joint deformity in CIA rats to varying degrees, reduce the clinical score, inhibit synovial inflammation, vascular opacification, cartilage erosion, and bone destruction, and reduce the number of TRAP-positive cells in bone tissue. Micro-CT results showed that the SA was able to increase bone mineral density, bone volume fraction, trabecular reduce, and trabecular number and reduce bone surface/bone volume and trabecular separation/spacing. Different doses of SA could down-regulate the protein expression of IL-1ß, p-JNK, p-ERK, p-p38, PI3K, and p-Akt to varying degrees. In conclusion, SA can improve disease severity, attenuate histopathological and imaging changes in joints, and have osteoprotective effects in CIA rats, and its mechanism of action may be related to the inhibition of the overactivation of MAPK and PI3K/Akt signaling pathways.

Effect of Myelin Debris on the Phenotypic Transformation of Astrocytes after Spinal Cord Injury in Rats.

After spinal cord injury (SCI), the accumulation of myelin debris can serve as proinflammatory agents, hindering axon regrowth and exacerbating damage. While astrocytes have been implicated in the phagocytosis of myelin debris, the impact of this process on the phenotypic transformation of astrocytes and their characteristics following SCI in rats is not well understood. Here, we demonstrated that the conditioned medium of myelin debris can trigger apoptosis in rat primary astrocytes in vitro. Using a compressional SCI model in rats, we observed that astrocytes can engulf myelin debris through ATP-binding cassette transporter sub-family A member 1 (ABCA1), and these engulfed cells tend to transform into A1 astrocytes, as indicated by C3 expression. At 4 days post-injury (dpi), astrocytes rapidly transitioned into A1 astrocytes and maintained this phenotype from 4 to 28 dpi, while A2 astrocytes, characterized by S100, were only detected at 14 and 28 dpi. Reactive astrocytes, identified by Nestin, emerged at 4 and 7 dpi, whereas scar-forming astrocytes, marked by N-cadherin, were evident at 14 and 28 dpi. This study illustrates the distribution patterns of astrocyte subtypes and the potential interplay between astrocytes and myelin debris after SCI in rats. We emphasize that myelin debris can induce astrocyte apoptosis in vitro and promote the transformation of astrocytes into A1 astrocytes in vivo. These two classification methods are not mutually exclusive, but rather complementary.