Leman Sencar

Macrophage depletion delays progression of neuropathic pain in diabetic animals

Despite the fact that it is a frequent diabetic complication, the mechanisms underlying the manifestation of diabetic neuropathic pain remain poorly understood. In this study, we hypothesized that the depletion of peripheral macrophages with liposome-encapsulated clodronate (LEC) can prevent, at least delay, the progression of diabetes-induced neuropathic pain. Therefore, the aim of this study was to evaluate the effects of macrophage depletion on mechanical allodynia and thermal hyperalgesia in the streptozotocin (STZ)-induced rat model of diabetic neuropathy. LEC was intravenously administrated to rats three times with 5-day intervals. A single intravenous injection of STZ caused an increase in the average blood glucose levels and a decrease in body weight. Although LEC treatment did not affect the body weight gain, the blood glucose level was lower and serum insulin level higher in LEC-treated diabetic rats than in that of diabetic rats. In addition, LEC treatment alleviated the excessive damage in beta cells in diabetic rats. Diabetic animals displayed marked mechanical allodynia and thermal hyperalgesia. While the treatment of diabetic rats with LEC did not significantly change the thermal withdrawal latency, diabetes-induced decrease in mechanical paw withdrawal threshold was significantly corrected by the LEC treatment. The results of this study show that thermal hyperalgesia and mechanical allodynia induced by diabetes may be associated with alterations in blood glucose level. Depletion of macrophages with LEC in diabetic rats may reduce mechanical allodynia without affecting thermal hyperalgesia. Taken together, these results suggested that depletion of macrophages in diabetes may partially postpone the development of diabetic neuropathic pain.

The effect of levetiracetam on neuronal apoptosis in neonatal rat model of hypoxic ischemic brain injury

BACKGROUND Hypoxic-ischemic brain injury (HIBI) is a common cause of neonatal mortality and morbidity. The use of levetiracetam (LEV), as a potential neuroprotective in brain ischemia, receives an increasingly high attention, and it could have a crucial role in the regulation of epileptogenesis and neuroprotection. Potential effects of LEV on neuronal apoptosis in HIBI have not previously been reported in literature. OBJECTIVES The aim of this study is to evaluate the possible effects of LEV on neuronal apoptosis in neonatal rat model of HIBI. METHODS Seven-day-old Wistar rat pups were subjected to right common carotid artery ligation and hypoxia (92% nitrogen and 8% oxygen) for 2h. The pups were treated with LEV or saline after hypoxia. In sham group rats, neither ligation, nor hypoxia was performed. Neuronal apoptosis was evaluated by the terminal deoxynucleotidyl-transferase- mediated dUTP nick-end labeling (TUNEL) methods. RESULTS The counts of apoptotic cells in both hippocampus and cerebral cortex were significantly higher in the saline treatment group than in the sham group. The counts of apoptotic cells in both hippocampus and cerebral cortex were similar to those in the sham group and in the LEV treatment group. The number of apoptotic cells decreased significantly in the LEV-treated group compared with the saline group. CONCLUSIONS These results show that LEV administration after hypoxia reduces neuronal apoptosis. Thus, we propose that LEV, as an effective antiepileptic and antiapoptotic drug, may be a viable choice for the control of seizure activity in neonates with HIBI.

Comparison of Vascularized Osteoperiosteal Femur Flaps and Nonvascularized Femur Grafts for Reconstruction of Mandibular Defects: An Experimental Study

PURPOSE The aim of this study was to compare the vascularized osteoperiosteal femur flaps (VFFs) and the nonvascularized femur grafts (NVFGs) for reconstruction of the mandibular defects of pigs. MATERIALS AND METHODS Eight adult domestic pigs were used. The defects created in the mandibular angle were reconstructed with VFFs in 4 pigs (group 1) and NVFGs in the other 4 pigs (group 2). All the pigs were killed after 3 months of healing. Undecalcified and decalcified sections were prepared for histomorphometric analysis and histologic examination. Radiodensitometric absorptiometry was used to assess the differences in bone mineral density between the 2 groups. RESULTS The bone volume to the total measured volume, trabecular thickness, and trabecular number were significantly greater in the VFF group than in the NVFG group (P < .05). However, the trabecular separation was significantly lower in the VFF group than the NVFG group (P = .029). Although the VFF group had a greater bone mineral density value than the NVFG group, the difference was not statistically significant (P = .057). In histologic examination, the viability of bone in the VFF group, enchondral bone healing, and lamellar bone formation in the NVFG group were apparent. CONCLUSIONS The results of this study suggest that NVFGs have a greater bone resorption rate than do VFFs. Furthermore, the histomorphometric results imply that reconstruction of the mandibular defects with vascularized osteoperiosteal femur flaps will provide greater strength.

Impacts of β-estradiol on intestinal injury in newborn rats.

Abstract Objective: Necrotizing enterocolitis has been investigated and debated extensively in recent years; however, there is still no effective treatment. The aim of this study was thus to examine the effects of β-estradiol on intestinal injury in rats. Methods: Twenty-four newborn female rat pups were divided into three groups. In group 1 (sham), hypoxia–re-oxygenation was not performed. In group 2 (saline), the rats were injected with saline after hypoxia–re-oxygenation, and the process was repeated for 5 d. In group 3 (β-estradiol treatment), the rats were subjected to hypoxia–re-oxygenation and then given β-estradiol intraperitoneally once a day for 5 d. After these procedures, the terminal ileum was removed for analysis. Results: Statistically significant differences in histological grades were found between groups 1 and 2 (p = 0.000), groups 1 and 3 (p = 0.028), and groups 2 and 3 (p = 0.021). There were also differences in TNF-α and IL-6 levels between groups 2 and 3 (p = 0.000 and p = 0.038, respectively) and between groups 1 and 2 (p = 0.000 and p = 0.000); there was no difference between groups 1 and 3 (p = 0.574 and p = 0.195, respectively). Electron microscopy examination revealed a decrease in lipid droplets at the apical cytoplasm of the columnar cells in group 2; in group 3, the absorption of the lipids as lipid droplets was similar to that of group 1. Conclusion: In this study, β-estradiol was found to decrease the intensity of intestinal injury significantly by inhibiting TNF-α and IL-6.

Comparative study of the osseous healing process following three different techniques of bone augmentation in the mandible: an experimental study

The aim of this study was to evaluate the osseointegration of three different bone grafting techniques. Forty-eight mature New Zealand rabbits were divided randomly into three groups of 16 each. Horizontal augmentation was performed on the corpus of the mandible using three different techniques: free bone graft (FBG), free periosteal bone graft (PBG), pedicled bone flap (BF). The animals were sacrificed at postoperative weeks 1, 3, or 8. Specimens were decalcified for histological examination, and histomorphometric measurements were performed. The histological evaluation demonstrated bony fusion between the grafts and the augmented mandibular bone after 8 weeks in all groups. At week 8, the bone volume was significantly greater in the BF group than in the FBG (P<0.001) and PBG (P=0.001) groups, and also the trabecular thickness was significantly greater than in the FBG (P=0.015) and PBG (P=0.015) groups. Trabecular separation was significantly lower in the BF group than in the FBG group at week 8 (P=0.015). BF demonstrated greater osseous healing capacity compared to FBG and PBG. The preserved vascularization in BF improves the bone quality in mandibular bone augmentations.

Effects of sodium selenite and amiloride on calvarial calcification in closing small cranial defects

OBJECT Fresh autogenous bone graft is the most preferred osteoplastic material, whether the purpose is cosmetic, psychological, or for the protection of the brain. These grafts are not rejected and do not react immunologically. The aim of this study was to evaluate the efficacy of autogenous fat rolled with bone dust derived from the bur hole in closing small cranial defects. Additionally, the authors examined the morphological and biochemical effects of Na selenite and amiloride on calvarial calcification. METHODS The study group consisted of 20 domestic pigs. These animals were randomly divided into 4 groups. A bur hole with a diameter of 10 mm was made at the right parietal region in all animals, and then the periosteum around the bur hole was cauterized following exposure of the dura mater. The dura was coagulated with bipolar cautery. Group 1 (controls): only a bur hole was opened, and it was then closed with a mixture of the bone dust that had been created during the opening of the bur hole and fat tissue that was taken from the animals neck. Group 2 (amiloride): 1 nmol/g body weight of amiloride was applied subcutaneously within 15 minutes after closure of the bur hole with bone dust and fat, and then amiloride was applied once a day for 4 weeks. Group 3 (Na selenite): 30 nmol/g body weight of Na selenite was applied subcutaneously within 30 minutes after closure of the bur hole with bone dust and fat, and then Na selenite was applied once a day for 4 weeks. Group 4 (amiloride and Na selenite): 1 nmol/g body weight of amiloride was applied subcutaneously at 15 minutes, and 30 nmol/g body weight of Na selenite was applied subcutaneously at 30 minutes after closure of the bur hole with bone dust and fat, and these 2 injections were repeated once a day for 4 weeks. At the end of 4 weeks, the animals were anesthetized to evaluate the closure of the bur hole. Tissue samples were obtained for ultrastructural and biochemical examination. RESULTS The defect was covered with diffuse connective tissue in the control group. Although multiple capillary vessels were present, the authors did not observe osteogenic differentiation. Histological examination of the second group revealed osteogenic changes. Although new matrix was formed, calcification was not detected. The authors observed fibroblast, collagen fibers, and dense connective tissue filled with capillary in the third group of pigs, which had undergone Na selenite application. Calcification was not detected in this group. Both connective and osteogenic tissue were observed in specimens obtained in the fourth group, which had undergone amiloride and Na selenite application. CONCLUSIONS The authors experimentally evaluated the supplementary osteogenic effects of Na selenite and amiloride by using them separately and together. The findings seem promising as a lead-in to new studies in restoring cranial defects.

Therapeutic Potential of Pterostilbene and Resveratrol on Biomechanic, Biochemical, and Histological Parameters in Streptozotocin-Induced Diabetic Rats

Aims The aim of this study was to investigate the effects of pterostilbene (PTS) (trans-3,5-dimethoxy-4′-hydroxystilbene) and resveratrol (RSV) (trans-3,5,4′ trihydroxystilbene) applied at different doses for the treatment of streptozotocin- (STZ-) induced diabetic rats. Materials and Methods At the end of the 5-week experimental period, the right gastrocnemius muscles of the rats were examined biomechanically, while the left ones were examined histologically. In addition, blood glucose, serum insulin, and malondialdehyde (MDA) levels were analyzed in blood samples taken from the rats. Results The skeletal muscle isometric contraction forces, which showed a decrease with diabetes, were observed to increase with antioxidant applications. Blood glucose, serum insulin, and MDA levels in diabetic rats approached normal levels after applying PTS. When the electron microscopic images of the rat skeletal muscle were examined, those in the combination treatment group were observed to show a better enhancement in the skeletal muscle morphological structure compared to the other diabetic and treatment groups. Conclusion According to the findings, we suggest that these antioxidant treatments might have good therapeutic nutraceutical potential for some muscle diseases that coexist with diabetes. These treatments should be comprehensively investigated in the future.

Early propranolol treatment amelioratesendothelial dysfunction in experimental septic lung

BACKGROUND Recent reports have indicated an improved prognosis in sepsis with beta blocker agents; however, the underlying action mechanism is still under debate. OBJECTIVES The aim of this study was to investigate the potential effect of propranolol on endothelial dysfunction in septic rats. MATERIAL AND METHODS The cecal ligation and puncture model (CLP) was used to generate sepsis. Adult male Wistar-Albino rats were divided into 4 groups: group 1 was a sham group, group 2 received sterile saline, group 3 received 10 mg/kg of propranolol 3 days before the intervention, and group 4 received 10 mg/kg of propranolol 30 min after CLP. Six rats from each group were sacrificed 24 h postoperatively. The remaining rats were followed for survival. We have also evaluated the effects on systemic inflammation, coagulation and the lung tissue with immunohistochemical and electron microscopic evaluation. RESULTS Serum tumor necrosis factor alpha (TNF-α) and plasminogen activator inhibitor-1 (PAI-1) levels, as well as tissue TNF-α scores were elevated in septic rats. Electron microscopic examination of the lung tissue showed endothelial dysfunction in the sepsis group. Pretreatment significantly improved survival. Moreover, pre-treatment altered serum vascular endothelial growth factor receptor-1 (VEGFR-1) levels and post-treatment reduced serum PAI-1 and VEGFR-1 levels. In both the preand post-treatment groups, electron microscopic examination revealed improvement of the destroyed lung endothelium and showed only mild alterations in the cytoplasmic organelles, especially in the mitochondria of the endothelial cells. CONCLUSIONS These results suggest that the improved outcome with beta blockers in sepsis may be due to the ameliorated endothelial dysfunction. Further studies focusing on the potential effect of beta blockers on the endothelium may lead to a better understanding of sepsis.

Effects of arginine vasopressin and v1 receptor antagonist on cerebral vasospasm secondary to subarachnoid hemorrhage: an experimental study

AIM To examine morphological, radiological and biochemical effects of arginine vasopressin (AV) and V1 receptor antagonist on cerebral vasospasm (CVS) after subarachnoid hemorrhage (SAH) in rabbits. MATERIAL AND METHODS Forty male New Zealand white rabbits were randomly divided into four groups comprising 10 rabbits each. The groups were; 1) Control group, 2) SAH group, 3) SAH+AV group, 4) SAH+V1 antagonist group. Diameters of the basilar artery in all groups were measured on angiograms. All animals were sacrificed two days following basilar angiography and tissue samples of basilar artery were obtained under microscope immediate after craniectomy for ultrastructural and biochemical examinations. RESULTS The artery diameters were found to be 50% and 50% at the 30th minute in the groups 2 and 3 respectively. In group 3, CVS was 13% more in comparison with the 2nd group. In group 4, vascular constriction was 34.5% at the 30th minute and about 30.9% at the 300th minute. Despite the increase in regional blood flow, AV did not provide morphological change. Histological appearance was related to vascular stenosis due to CVS. Histological outcome was the best in group 4 because of less CVS. CONCLUSION Arginine vasopressin plays an important role in CVS. We detected morphological and radiological recovery in basilar artery, besides moderate improvement due to AV receptor antagonist in CVS.

Arterialized Venous Bone Flaps: An Experimental Investigation.

In arterialized venous flaps (AVFs) the venous network is used to revascularize the flap. While the feasibility of AVFs in soft tissues has been reported there is no study on osseous AVFs. In this study we aim to assess the flap survival of osseous AVFs in a pig model. Medial femoral condyle flaps were elevated in 18 pigs. Three groups were created: AVF (n = 6), conventional arterial flap (cAF, n = 6) and bone graft (BG, n = 6). The AVFs were created by anastomosis of genicular artery with one vena comitans while leaving one efferent vein for drainage. After 6 months the specimens were harvested. The histology and histomorphometry of of the bone in cAF and AVF was significantly superior to bone grafts with a higher bone volume in AVFs (p = 0.01). This study demonstrates that osseous free flaps may be supported and survive using the technique of arterialization of the venous network. The concept of AVFs in osseous flaps may be feasible for revascularization of free flaps with an inadequate artery but well developed veins. Further experimental and clinical studies are needed to assess the feasibility of clinical use of arterialized venous bone flaps.