Rat Head Research Articles

Tension-Free Weight-Bearing Model of Steroid-Induced Osteonecrosis of Femoral Head in Rats.

Unlike humans, rats are animals that walk on all fours, while humans are bipedal animals that stand, and the hips are subjected to tremendous pressure when walking and standing. In rat steroid-induced femoral head necrosis models, the biomechanical characteristics of the human hip under higher pressure often need to be simulated. Some scholars try to emulate the state of human hip pressure by making rats bear a certain weight, but fixing the weight-bearing object on the rat is tough. Rats can easily break free of immobilization, and sticking the weight on the rats with adhesive tape will cause the rats to suffocate or die from intestinal obstruction. Our research group used elastic therapeutic tape to perform tension-free immobilization of weight-bearing objects in rats so that the rats could breathe freely and not break away from the immobilization under weight-bearing conditions. Compared to the usual steroid-induced femoral head necrosis rat model, we found that this weight-bearing intervention can aggravate the progression of femoral head necrosis in rats.

A Technique to Isolate Satellite Cells From Rat Head Muscle Tissue

A Technique to Isolate Satellite Cells From Rat Head Muscle Tissue

A Technique to Isolate Satellite Cells From Rat Head Muscle Tissue

A Technique to Isolate Satellite Cells From Rat Head Muscle Tissue

Effect of genetically engineered drugs in aseptic necrosis of the femoral head in rats

Bone tissue is a dynamic structure with a metabolic function. The maintenance of bone homeostasis is carried out due to the continuous process of its renewal, remodeling. At the same time, a number of pathological processes, such as ischemic catastrophe, can lead to a violation of the balance of maintaining the constancy of the bone structure. One of these diseases is aseptic necrosis of the femoral head. The presented study analyzes the dynamics of expression of genes involved in maintaining bone tissue homeostasis, changes in the histological picture during the development of aseptic necrosis of the femoral head in laboratory rats that did not receive genetically engineered drugs and against the background of the use of inhibitors of biological action IL-6, TNF-α. After induction of aseptic necrosis in the proximal epiphysis of the femur, the histological picture in animals of different groups was not the same. More preserved bone architectonics and a larger volume of bone plates were recorded in rats receiving genetically engineered drugs compared to animals without the introduction of biological agents. The latter also had the most vivid picture of osteodestruction with increased expression of proinflammatory cytokine genes. In animals, against the background of the use of drugs of inhibitors of the biological action of IL-6, TNF-α, from the second week after induction of aseptic necrosis of the mRNA, the profile of the spongiose bone of the proximal epiphysis of the femur tended to increase the expression of osteoreparation genes. At the same time, the greatest inhibition of osteoclastogenesis gene expression was obtained in rats after injection of a monoclonal antibody to the IL-6 receptor.

α7nAChR-mediated astrocytic activation: A novel mechanism of Xiongzhi Dilong decoction in ameliorating chronic migraine

Ethnopharmacological relevanceAlpha 7 nicotinic acetylcholine receptor (α7nAChR)-mediated astrocytic activation is closely related to central sensitization of chronic migraine (CM). Xiongzhi Dilong decoction (XZDL), originated from Xiongzhi Shigao decoction of Yi-zong-jin-jian, has been confirmed to relieve CM in experiment and clinic. However, its underlying mechanism for treating CM has not been elucidated. Aim of the studyTo reveal the underlying mechanisms of XZDL to alleviate CM in vivo focusing mainly on α7nAChR-mediated astrocytic activation and central sensitization in TNC. Materials and methodsCM rat model was established by subcutaneous injection of nitroglycerin (NTG) recurrently, and treated with XZDL simultaneously. Migraine-like behaviors of rats (ear redness, head scratching, and cage climbing) and pain-related reactions (mechanical hind-paw withdrawal threshold) of rats were evaluated before and after NTG injection and XZDL administration at different points in time for nine days. The immunofluorescence single and double staining were applied to detect the levels of CGRP, c-Fos, GFAP and α7nAChR in NTG-induced CM rats. ELISA kits were employed to quantify levels of TNF-α, IL-1β, and IL-6 in medulla oblongata of CM rats. The expression levels of target proteins were examined using western blotting. Finally, methyllycaconitine citrate (MLA, a specific antagonist of α7nAChR) was applied to further validate the mechanisms of XZDL in vivo. ResultsXZDL significantly attenuated the pain-related behaviors of the NTG-induced CM rats, manifesting as constraints of aberrant migraine-like behaviors including elongated latency of ear redness and decreased numbers of head scratching and cage climbing, and increment of mechanical withdrawal threshold. Moreover, XZDL markedly lowered levels of CGRP and c-Fos, as well as inflammatory cytokines (IL-1β, IL-6 and TNF-α) in CM rats. Furthermore, XZDL significantly enhanced α7nAChR expression and its co-localization with GFAP, while markedly inhibited the expression of GFAP and the activation of JAK2/STAT3/NF-κB pathway in the TNC of CM rats. Finally, blocking α7nAChR with MLA reversed the effects of XZDL on astrocytic activation, central sensitization, and the pain-related behaviors in vivo. ConclusionXZDL inhibited astrocytic activation and central sensitization in NTG-induced CM rats by facilitating α7nAChR expression and suppressing JAK2/STAT3/NF-κB pathway, implying that the regulation of α7nAChR-mediated astrocytic activation represents a novel mechanism of XZDL for relieving CM.

Effects and Significance of Dicliptera chinensis Polysaccharide on the Expression of Transforming Growth Factor β1/Connective Tissue Growth Factor Pathway in the Masseter and Head and Neck Skin of Rats With Radiation-Induced Fibrosis

PurposeTo investigate whether Dicliptera chinensis polysaccharide (DCP) can alleviate radiation-induced fibrosis of masseter and head and neck skin. MethodsSD rats were divided into the control, the irradiation (IR), the IR + low dose DCP (200 mg/kg), and the IR + high dose DCP (400 mg/kg) groups. The head and neck of rats in the last 3 groups received a single dose of 18 Gy X-ray. At 1st, 2nd, 4th week (w) after radiation, haematoxylin and eosin staining were performed on masseter and skin to observe the histopathological changes; immunohistochemistry staining was performed to observe the pathological changes of the skin; Masson staining was performed on masseter and skin to observe the collagen deposition; western blot analysis was used on masseter to calculate the relative transforming growth factor β1 (TGF-β1), connective tissue growth factor (CTGF) expressions; ELISA was used to detect the contents of TGF-β1 and CTGF in skin and the contents of type I and type III collagens in masseter and skin. ResultsIn terms of skin, compared to the IR group, the IR + high-dose DCP group exhibited relatively smaller changes in skin structure, lower levels of TGF-β1 and CTGF; thinner skin thickness was observed at the 4th w after radiation; and the positive rates of collagen fibre and the optical densities of type I and type III collagens were lower at the 2nd and 4th w. For the masseter, compared to the IR group, the morphological changes were improved and the expression levels of TGF-β1 and CTGF proteins decreased in the 2 DCP dose groups at 2nd and 4th w. ConclusionDCP can reduce the formation and accumulation of type I and type III collagens after IR and ameliorate radiation-induced fibrosis of masseter and skin by down-regulating the expressions of TGF-β1 and CTGF.

The effect of the IL-6 monoclonal blocker on the course of aseptic femoral head necrosis in the experiment (pilot study)

Background There is currently no pathogenetically based treatment for aseptic necrosis of the femoral head. One of the most promising areas of possible targeted therapy is the use of genetically engineered drugs, including monoclonal blockers of proinflammatory cytokines, aimed at inhibiting inflammation and indirectly reducing the activity of osteodestruction. The aim of the work is to evaluate the effectiveness of the use of the IL-6 monoclonal blocker in the course of aseptic necrosis of the femoral head in an experiment.Purpose Evaluate the preliminary results of the use of the IL-6 monoclonal blocker in the course of aseptic necrosis of the femoral head in an experiment.Materials and methods Surgical induction of aseptic necrosis of the femoral head was performed in 18 male Wistar rats. The animals were divided into two groups of 9 individuals each. The first group did not receive any treatment, the second received therapy with a monoclonal IL-6 receptor blocker, starting from the second week of the experiment, one injection once every two weeks. All animals were removed from the experiment at 4, 6 and 8 weeks after the induction of aseptic necrosis, 3 rats from each group at a time. Total RNA was isolated from the femoral head on the aseptic necrosis side and the conditionally healthy side as a control. The expression of genes of regulatory proteins of osteogenesis was studied by PCR. To study the features of osteodestructive processes, histological examination of femoral head preparations in all animals was conducted.Results Histological preparations of femoral heads of the second group animals were characterized by less pronounced osteodestructive, chondrodestructive processes compared to the animals that did not receive therapy. The mRNA profile of the rats of the second group displayed an increase in the expression of genes encoding proteins involved in osteoreparation at all stages of the experiment. At the same time, the activity of genes encoding proteins of proinflammatory cytokines, regulatory molecules of osteoclastogenesis was reduced relative to the first group.Discussion The data obtained indicate an important role of inflammation in the regulation of osteodestruction. Inhibition of the biological action of IL-6 contributed to inhibition of the expression of osteoclastogenesis genes, increased activity of bone metabolism genes, and caused a decrease in the intensity of osteodestruction and activation of osteoreparation. Conclusion Preliminary results of the use of a monoclonal blocker of the proinflammatory cytokine IL-6 indicate the inhibition of osteodestructive and strengthening of osteoreparative processes due to the correction of the expression of bone metabolism genes during the progression of aseptic necrosis of the femoral head in rats in an experimental model.

Palliative effect of rotating magnetic field on glucocorticoid-induced osteonecrosis of the femoral head in rats by regulating osteoblast differentiation

With the substantial increase in the overuse of glucocorticoids (GCs) in clinical medicine, the prevalence of glucocorticoid-induced osteonecrosis of the femoral head (GC-ONFH) continues to rise in recent years. However, the optimal treatment for GC-ONFH remains elusive. Rotating magnetic field (RMF), considered as a non-invasive, safe and effective approach, has been proved to have multiple beneficial biological effects including improving bone diseases. To verify the effects of RMF on GC-ONFH, a lipopolysaccharide (LPS) and methylprednisolone (MPS)-induced invivo rat model, and an MPS-induced invitro cell model have been employed. The results demonstrate that RMF alleviated bone mineral loss and femoral head collapse in GC-ONFH rats. Meanwhile, RMF reduced serum lipid levels, attenuated cystic lesions, raised the expression of anti-apoptotic proteins and osteoprotegerin (OPG), while suppressed the expression of pro-apoptotic proteins and nuclear factor receptor activator-κB (RANK) in GC-ONFH rats. Besides, RMF also facilitated the generation of ALP, attenuated apoptosis and inhibits the expression of pro-apoptotic proteins, facilitated the expression of OPG, and inhibited the expression of RANK in MPS-stimulated MC3T3-E1 cells. Thus, this study indicates that RMF can improve GC-ONFH in rat and cell models, suggesting that RMF have the potential in the treatment of clinical GC-ONFH.

Effect of collagen sponge combined with epidermal growth factor in repairing maxillofacial head and neck wounds in rats.

Collagen sponge and epidermal growth factor (EGF) promote wound healing. However, the effect of collagen sponge combined with EGF in repairing maxillofacial head and neck wounds remains unclear. The rats were divided into 3 groups, including experimental group 1 (Vaseline gauze+EGF), experimental group 2 (collagen sponge+EGF) with control group (Vaseline+normal saline), and maxillofacial head and neck wounds were simulated. Wound pathological morphology was detected by HE staining; wound EGF, IL-1β, IL-6 along with TNF-α contents by ELISA and MMP1 level by western blot. At 7 and 14 days after treatment, wound healing rate of two experimental groups was higher than that of control group, and that of experimental group 2 presented higher than that of experimental group 1. Compared with control group, experimental group 1 had significantly fewer inflammatory cells in the wound tissue, local erythrocyte spillage outside the vascular walls, more collagen deposition and more granulation tissue. Compared with experimental group 1, inflammatory cells in wound tissues of experimental group 2 were significantly reduced, the collagen tissues were visible and arranged, and the growth of the wound granulation tissue was obvious. IL-1β, IL-6 along with TNF-α levels in two experimental groups presented lower than control group, and EGF level was higher. More importantly, in contrast to experimental group 1, IL-1β, IL-6 along with TNF-α in experimental group 2 presented lower, and EGF level presented higher. At 14 days after treatment, MMP1 level in two experimental groups was lower than control group. In contrast to experimental group 1, MMP1 level in experimental group 2 was lower. In summary, collagen sponge combined with EGF for the first time significantly improved the healing speed of maxillofacial head and neck wounds and reduced the scar left after wound healing.

Astaxanthin-mediated Nrf2 activation ameliorates glucocorticoid-induced oxidative stress and mitochondrial dysfunction and impaired bone formation of glucocorticoid-induced osteonecrosis of the femoral head in rats

BackgroundOsteonecrosis of the femoral head caused by glucocorticoids (GIONFH) is a significant issue resulting from prolonged or excessive clinical glucocorticoid use. Astaxanthin, an orange-red carotenoid present in marine organisms, has been the focus of this study to explore its impact and mechanism on osteoblast apoptosis induced by dexamethasone (Dex) and GIONFH.MethodsIn this experiment, bioinformatic prediction, molecular docking and dynamics simulation, cytotoxicity assay, osteogenic differentiation, qRT-PCR analysis, terminal uridine nickend labeling (TUNEL) assay, determination of intracellular ROS, mitochondrial function assay, immunofluorescence, GIONFH rat model construction, micro-computed tomography (micro-CT) scans were performed.ResultsOur research demonstrated that a low dose of astaxanthin was non-toxic to healthy osteoblasts and restored the osteogenic function of Dex-treated osteoblasts by reducing oxidative stress, mitochondrial dysfunction, and apoptosis. Furthermore, astaxanthin rescued the dysfunction in poor bone quality, bone metabolism and angiogenesis of GIONFH rats. The mechanism behind this involves astaxanthin counteracting Dex-induced osteogenic damage by activating the Nrf2 pathway.ConclusionAstaxanthin shields osteoblasts from glucocorticoid-induced oxidative stress and mitochondrial dysfunction via Nrf2 pathway activation, making it a potential therapeutic agent for GIONFH treatment.

Chemopreventive Role of Sulindac Sulfone on 4-nitroquinoline 1-oxide-induced Head and Neck Squamous Cell Carcinogenesis in Rats

Chemopreventive Role of Sulindac Sulfone on 4-nitroquinoline 1-oxide-induced Head and Neck Squamous Cell Carcinogenesis in Rats

Jintiange capsule ameliorates glucocorticoid-induced osteonecrosis of the femoral head in rats by regulating the activity and differentiation of BMSCs

Background and aimA surplus of glucocorticoids (GC) is a main cause of non-traumatic osteonecrosis of the femoral head (ONFH), and Jintiange (JTG), as one of the traditional Chinese medicines (TCM), also plays an instrumental role in the alleviation of bone loss simultaneously. Therefore, JTG was thought to be able to reverse GC-induced ONFH (GC-ONFH) to a certain extent. Experimental procedureIn vivo, the effect of JTG on trabeculae in the subchondral bone of the femoral head was investigated using micro-computed tomography (micro-CT), TdT-mediated dUTP nick end labeling (TUNEL) and histological staining; in vitro, proliferation, viability, apoptosis, and senescence of purified bone mesenchymal stem cells (BMSCs) were examined to demonstrate the direct impact of JTG on these cells. Meanwhile after using a series of interventions, the function of JTG on BMSC differentiation could be assessed by measuring of osteogenic and adipogenic markers at levels of protein and mRNA. ResultsOur final results demonstrated that with the involvement of Wnt/β-catenin pathway, JTG was able to significantly promote osteogenesis, restrain adipogenesis, delay senescence in BMSCs, reduce osteoclast number, weaken apoptosis, and enhance proliferation of osteocytes, all of which could mitigate the progression of subchondral osteonecrosis. ConclusionAccording to the results of experiments in vitro and vivo, JTG was deemed to relieve the early GC-ONFH using the prevention of destruction of subchondral bone, which was contributed to regulating the differentiation of BMSCs and the number of osteoclasts.

Dexamethasone Induced Osteocyte Apoptosis in Steroid-Induced Femoral Head Osteonecrosis through ROS-Mediated Oxidative Stress.

Glucocorticoid (GC) overuse is strongly associated with steroid-induced osteonecrosis of the femoral head (SINFH). However, the underlying mechanism of SINFH remains unclear. This study aims to investigate the effect of dexamethasone (Dex)-induced oxidative stress on osteocyte apoptosis and the underlying mechanisms. Ten patients with SINFH and 10 patients with developmental dysplasia of the hips (DDH) were enrolled in our study. Sixty rats were randomly assigned to the Control, Dex, Dex + N-Acetyl-L-cysteine (NAC), Dex + Dibenziodolium chloride (DPI), NAC, and DPI groups. Magnetic resonance imaging (MRI) was used to examine edema in the femoral head of rats. Histopathological staining was performed to assess osteonecrosis. Immunofluorescence staining with TUNEL and 8-OHdG was conducted to evaluate osteocyte apoptosis and oxidative damage. Immunohistochemical staining was carried out to detect the expression of NOX1, NOX2, and NOX4. Viability and apoptosis of MLO-Y4 cells were measured using the CCK-8 assay and TUNEL staining. 8-OHdG staining was conducted to detect oxidative stress. 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) staining was performed to measure reactive oxygen species (ROS). The expression of NOX1, NOX2, and NOX4 in MLO-Y4 cells was analyzed by Western blotting. Multiple comparisons were performed using one-way analysis of variance (ANOVA). In patients and the rat model, hematoxylin-eosin (HE) staining revealed a significantly higher rate of empty lacunae in the SINFH group than in the DDH group. Immunofluorescence staining indicated a significant increase in TUNEL-positive cells and 8-OHdG-positive cells in the SINFH group compared to the DDH group. Immunohistochemical staining demonstrated a significant increase in the expression of NOX1, NOX2, and NOX4 proteins in SINFH patients compared to DDH patients. Moreover, immunohistochemical staining showed a significant increase in the proportion of NOX2-positive cells compared to the Control group in the femoral head of rats. In vitro, Dex significantly inhibited the viability of osteocyte cells and induced apoptosis. After Dex treatment, the intracellular ROS level increased. However, Dex treatment did not alter the expression of NOX proteins in vitro. Additionally, NAC and DPI inhibited the generation of intracellular ROS and partially alleviated osteocyte apoptosis in vivo and in vitro. This study demonstrates that GC promotes apoptosis of osteocyte cells through ROS-induced oxidative stress. Furthermore, we found that the increased expression of NOXs induced by GC serves as an important source of ROS generation.

Echinacoside alleviates glucocorticoid induce osteonecrosis of femoral head in rats through PI3K/AKT/FOXO1 pathway

Steroid-induced osteonecrosis of the femoral head (SONFH), caused by glucocorticoid (GC) administration, is known to exhibit a high incidence worldwide. Although osteoblast apoptosis has been reported as an important cytological basis of SONFH, the precise mechanism remains elusive. Echinacoside (Ech), a natural phenylethanoid glycoside, exerts multiple beneficial effects, such as facilitation of cell proliferation and anti-inflammatory and anticancer activities. Herein, we aimed to explore the regulatory mechanism underlying glucocorticoid-induced osteoblast apoptosis and determine the protective efficacy of Ech against SONFH. We comprehensively surveyed multiple public databases to identify SONFH-related genes. Using bioinformatics analysis, we identified that the PI3K/AKT/FOXO1 signaling pathway was most strongly associated with SONFH. We examined the protective effect of Ech against SONFH using in vivo and in vitro experiments. Specifically, dexamethasone (Dex) decreased p-PI3K and p-AKT levels, which were reversed following Ech addition. Validation of the PI3K inhibitor (LY294002) and molecular docking of Ech and PI3K/AKT further indicated that Ech could directly enhance PI3K/AKT activity to alleviate Dex-induced inhibition. Interestingly, Dex upregulated the expression of FOXO1, Bax, cleaved-caspase-9, and cleaved-caspase-3 and enhanced MC3T3-E1 apoptosis; application of Ech and siRNA-FOXO1 reversed these effects. In vitro, Ech decreased the number of empty osteocytic lacunae, reduced TUNEL and FOXO1 positive cells, and improved bone microarchitecture. Our results provide robust evidence that PI3K/AKT/FOXO1 plays a crucial role in the development of SONFH. Moreover, Ech may be a promising candidate drug for the treatment of SONFH.

Research on online public opinion dissemination and emergency countermeasures of food safety in universities-take the rat head and duck neck incident in China as an example.

In recent years, food safety accidents have occurred frequently in colleges and universities, and students are prone to emotional resonance with food safety. It triggered heated discussions among the whole society and gradually formed a unique online public opinion on food safety in universities. After food safety incidents broke out in universities, some universities deliberately avoided responsibility or made mistakes in handling the incidents, which will create greater risks of online public opinion. Therefore, this paper takes the "Rat Head and Duck Neck" incident at Jiangxi Institute of Technology in China as an example. The purpose is to study the dissemination of public opinion on food safety online in universities and propose emergency countermeasures. Above all, the food safety online public opinion is divided into five stages: incubation period, burst period, spreading period, recurring period and dissipation period. Then, methods such as text mining and cluster analysis were used to deeply analyze the influencing factors at each stage of the development of food safety online public opinion. And analyze the role of different subjects in the development of public opinion based on the perspective of stakeholders. Finally, this paper provides corresponding countermeasures for different stages of online public opinion on food safety in universities, which provides suggestions and references for university governance. This study found that: (1) The resonance effect of online public opinion media on food safety in universities is significant. (2) Public opinion on food safety in universities is repetitive. (3) Improper response to food safety incidents in universities can easily trigger negative secondary public opinion.

Characterization of Induced Current Density During Transcorneal Electrical Stimulation to Promote Neuroprotection in the Degenerating Retina.

Transcorneal electrical stimulation (TES) is a promising approach to delay retinal degeneration by inducing extracellular electric field-driven neuroprotective effects within photoreceptors. Although achieving precise electric field control is feasible in vitro, characterizing these fields becomes intricate and largely unexplored in vivo due to uneven distribution in the heterogeneous body. In this paper, we investigate and characterize electric fields within the retina during TES to assess the potential for therapeutic approaches Methods: We developed a computational model of a rat's head, enabling us to generate predictive simulations of the voltage and current density induced in the retina. Subsequently, an in vivo experimental setup involving Royal College of Surgeon (RCS) rats was implemented to measure the voltage across the retina using identical electrode configurations as employed in the simulations. A stimulation amplitude of 0.2-0.3 mA may be necessary during TES in rats to induce a current density of at least 20 A/m2 in the retina, which is the lower limit for triggering neuroprotective effects according to culture studies on neural cells. Measurement taken from cadaveric pigs' eyes revealed that a stimulation amplitude of 1 mA is necessary for achieving the same current density. The computational modeling approach presented in this study was validated with experimental data and can be leveraged for predictive simulations to optimize the electrode design and stimulation parameters of TES. Once validated, the flexibility and low research cost of computational models are valuable in optimization studies where testing on live subjects is not feasible.

Novel multi-magnetic material transcranial magnetic stimulation coils for small animals application

Transcranial magnetic stimulation (TMS) is a non-invasive therapeutic approach with proven efficacy in treating certain psychiatric and neurological disorders. To broaden the application of TMS to a wider range of neurological disorders, the induced electric field (e-field) must be able to more focally target specific regions of the brain. Animal coil designs are promising for studying TMS effects and developing new procedures for treating various neurological and psychiatric disorders. However, investigations have mostly used coil designs intended for humans, and, as such, have failed to scale down for small animal sizes. Currently available coil systems have been limited by not adequately incorporating ideal soft magnetic materials as coil cores and not advancing the coil shapes for small animals as is necessary to achieve highly focused e-field concentration. In this study, we used multi-magnetic materials in TMS coils for the first time to our knowledge. We also considered the non-linear, hysteretic behavior of the cores in our FEM simulations of induced e-field and magnetic field in the brain models of the rat. Our study involved a comprehensive assessment of the distribution and intensity of the e-field across various coil configurations using our customized anatomically accurate rat head model. Iron-cobalt-vanadium (Permendur) alloy known for its high relative permeability, high saturation magnetization and low coercivity was used as the core material for all simulations. To enhance coil focality and concentration of the e-field, while avoiding stimulation of adjacent regions, we introduced a shape-conforming, flexible, diamagnetic pyrolytic graphite with susceptibility of -4.5×10-4 for our top performing coil. Simulation results were validated by comparing the simulated magnetic field results with experimental measurements obtained from the v-tip coil with a carbon steel AISI-1010 core at varying tip distances. This thorough study advances our knowledge of TMS coil designs and their optimization, particularly for small animal applications.

Effects of Estrogen on Histomorphology Steroid-Induced Avascular Necrosis of Head of Femur in Male Rats

Objectives: To study the effects of estrogen administration on histomorphology of avascular necrosis of the femoral head in male rats. Study Design: Lab-based experimental study. Place and Duration of Study: Department of Anatomy, Army Medical College, National University of Medical Sciences, Rawalpindi (NUMS), in collaboration with the National Institute of Health Islamabad, (NIH) Pakistan from Aug to Nov 2021. Methodology: Thirty male Sprague Dawley rats, three months of age, weighing 200-300 gm, were selected. Rats were equally divided into three groups. Group-A served as a control group in which no intervention was made, and the rats were fed on a standard lab diet. Groups B and C served as experimental groups. In Groups B and C, avascular necrosis was induced by steroids for the first week of the study. Group C along with steroids also received tab estrogen by oral gavage for eight weeks, starting from the fifth week of the study till the twelfth week of the study. All the rats were sacrificed after the completion of the experimental period. The microscopic parameters like cortical thickness and percentage of the empty lacunae were counted. Results: Histomorphological changes were observed when the comparison was made between Group B, Control Group A, and Experimental Groups B and C with statistically significant results (p-value 0.001). Conclusion: Estrogen helps in fracture healing and shows improvement in cortical and trabecular strength. It has shown improvement in the cortical thickness measurement after avascular necrosis causes a decrease in the thickness.

Erythropoietin suppresses osteoblast apoptosis and ameliorates steroid-induced necrosis of the femoral head in rats by inhibition of STAT1-caspase 3 signaling pathway

BackgroundSteroid-induced avascular necrosis of the femoral head (SANFH) is characterized by osteoblast apoptosis, leading to a loss of bone structure and impaired hip joint function. It has been demonstrated that erythropoietin (EPO) performs a number of biological roles.ObjectiveWe examined the effects of EPO on SANFH and its regulation of the STAT1-caspase 3 signaling pathway.MethodIn vitro, osteoblasts were treated with dexamethasone (Dex) or EPO. We identified the cytotoxicity of EPO by CCK-8, the protein expression of P-STAT1, cleaved-caspase9, cleaved-caspase3, Bcl-2, BAX, and cytochrome c by Western blotting, and evaluated the apoptosis of osteoblasts by flow cytometry. In vivo, we analyzed the protective effect of EPO against SANFH by hematoxylin and eosin (H&E), Immunohistochemical staining, and Micro-computed tomography (CT).ResultsIn vitro, EPO had no apparent toxic effect on osteoblasts. In Dex-stimulated cells, EPO therapy lowered the protein expression of BAX, cytochrome c, p-STAT1, cleaved-caspase9, and cleaved-caspase3 while increasing the expression of Bcl-2. EPO can alleviate the apoptosis induced by Dex. In vivo, EPO can lower the percentage of empty bone lacunae in SANFH rats.ConclusionThe present study shows that EPO conferred beneficial effects in rats with SANFH by inhibiting STAT1-caspase 3 signaling, suggesting that EPO may be developed as a treatment for SANFH.

The protective role of vitamins C and E in steroid-induced femoral head osteonecrosis: An experimental study in rats.

This study aimed to determine whether vitamin C (VC) and vitamin E (VE) can effectively protect the femoral head and reduce the risk of developing osteonecrosis in rats that have been treated with steroids. The study was conducted on 30 young adult male Sprague-Dawley rats (mean weight: 356±18 g; range, 330 to 375 g), which were randomly assigned to one of five groups. The control group received saline solution, while the other groups were given lipopolysaccharide/methylprednisolone (LPS/MPS) to induce osteonecrosis. Three groups in which osteonecrosis was induced were also intraperitoneally administered either VC, VE, or both once a day for four weeks. Intracardiac blood samples were taken at the end of the fourth week for biochemical examination, and the rats were then sacrificed under general anesthesia. After sacrification, right femurs were removed for histopathological, immunohistochemical, and radiologic examinations. The results showed that the mean trabecular number increased significantly in the VC+VE group. There was a substantial decrease observed in the mean trabecular separation within the LPS/MPS group compared to the control group, although trabecular separation decreased in all three vitamin groups compared to the LPS/MPS group. The surface area/bone volume was significantly increased in the VC+VE group compared to the LPS/MPS group. Histological, immunohistochemical, and radiological examinations showed that the administration of VC and VE significantly reduced oxidative stress, inflammation, and microvascular dysfunction in rats with steroid-induced femoral head osteonecrosis. This study suggests that VC, VE, and particularly VC+VE have a protective effect on the femoral head in rats with steroid-induced femoral head osteonecrosis. These findings may lead to new treatment options for patients.