Neuroprotective role of delta opioid receptors in hypoxic preconditioning

Background/aim: The purpose of the present study was to explore the neuroprotective role of delta opioid receptors (DOR) in the rat cortex in hypoxic preconditioning. Materials and methods: Rats were randomly divided into 8 groups: control (C), sham (S), hypoxic preconditioning (PC), severe hypoxia (SH), PC + SH, PC + SH + Saline (PS), PC + SH + DPDPE (DPDPE, selective DOR agonist), PC + SH + NT (NT, Naltrindole, selective DOR antagonist). Drugs were administered intracerebroventrically. Twenty four h after the end of 3 consecutive days of PC (10% O2, 2 h/day), the rats were subjected to severe hypoxia (7% O2 for 3 h). Bcl-2 and cyt-c were measured by western blot, and caspase-3 was observed immunohistochemically. Results: Bcl-2 expressions in the PC group were higher than in control, SH, and PC + SH groups. Even though there were no significant differences between the groups in terms of cyt-c levels, caspase-3 immunoreactivity of cortical neurons and glial cells in the severe hypoxia and NT groups were higher than in the control, sham, and hypoxic preconditioning groups. DPDPE administration diminished caspase-3 immunoreactivity compared with all of the severe hypoxia groups. Conclusions: These results suggest that cortical cells are resistant to apoptosis via increased expression of Bcl-2 and decreased immunoreactivity of caspase-3 in the cortex, and that DOR is involved in neuroprotection induced by hypoxic preconditioning via the caspase-3 pathway in cortical neurons.

The Effects of Riluzole on Cisplatin-induced Ototoxicity.

Introduction Riluzole (2-amino-6-trifluoromethoxy benzothiazole) is known as a neuroprotective, antioxidant, antiapoptotic agent. It may have beneficial effects on neuronal cell death due to cisplatin-induced ototoxicity. Objective To evaluate the effect of riluzole on cisplatin-induced ototoxicity in guinea pigs. Methods Twenty-four guinea pigs, studied in three groups, underwent auditory brainstem response evaluation using click and 8 kHz tone burst stimuli. Subsequently, 5 mg/kg of cisplatin were administered to all animals for 3 days intraperitoneally (i.p.) to induce ototoxicity. Half an hour prior to cisplatin, groups 1, 2 and 3 received 2 ml of saline i.p., 6 mg/kg of riluzole hydrochloride i.p., and 8 mg/kg of riluzole hydrochloride i.p., respectively, for 3 days. The auditory brainstem responses were repeated 24 hours after the last drug administration. The cochleae were analyzed by transmission electron microscopy (TEM). Results After drug administiration, for 8,000 Hz stimulus, group 1 had significantly higher threshold shifts when compared with groups 2 ( p < 0.05) and 3 ( p < 0.05), and there was no significant difference in threshold shifts between groups 2 and 3 ( p > 0.05). Transmission electron microscopy findings demonstrated the protective effect of riluzole on the hair cells and the stria vascularis, especially in the group treated with 8 mg/kg of riluzole hydrochloride. Conclusion We can say that riluzole may have a protective effect on cisplatin- induced ototoxicity. However, additional studies are needed to confirm these results and the mechanisms of action of riluzole.

Is leptin receptor expression triggered in the case of embryo transfer to endometrium coculture?

Background/aim: A synchronized dialogue between maternal and embryonic tissues is required for successful implantation. Low uterine receptivity is responsible for two-thirds of implantation failures and leptin is effective in the physiology of reproduction by binding to specific receptors. In this study, we investigateleptin receptor expression in cases of embryo transfer to endometrial coculture. Materials and methods: Biopsy materials were taken from 20 females with indication for coculture application and were cultured in an appropriate medium after the epithelial cells were isolated. The grown cells were cultured in chamber slides as the first group. For the second group, day 3 embryo was added to chamber slides and the development was observed. The embryo was transferred 1 or 2 days later and other cells (after the transfer process) were used to form the second group. After fixation, immunohistochemical staining was performed with anti-leptin primary antibody. Results: Regarding the coculture without embryo transfer, moderate leptin receptor immunoreactivity was seen in the perinuclear region and the cell membrane. Also, regarding the coculture with embryo transfer, moderate leptin receptor immunoreactivity was seen in the cytoplasm and strong leptin receptor immunoreactivity was seen in the cell membrane. Conclusion: Embryo transfer to endometrium coculture triggers leptin receptor expression

Examining the protective effects of acetyl l-carnitine on cisplatin-induced uterine tube toxicity.

The aim of this study was to investigate the effects of cisplatin and the protective role of acetyl l-carnitine against uterine tube toxicity. Twenty-four female Wistar albino rats were divided into four groups: control group was injected with saline (control); group 2 was injected with acetyl l-carnitine; group 3 was injected with cisplatin; and group 4 was pre-treated with acetyl l-carnitine before cisplatin intraperitoneal injection. According to our results, a significant weight loss was observed in rats from group 3. The thickness of the wall and epithelium of uterine tube were decreased in group 3 rats. We elaborate the protein expression of caspase in epithelium and stroma by IHC. We found that the expression of caspase and the number of TUNEL-positive cells were increased in group 3 rats compared to the other groups. In our study, we showed the protective role of acetyl l-carnitine against uterine tube toxicity caused by cisplatin.

The effect of di-n-butyl phthalate on testis and the potential protective effects of resveratrol.

This study aimed to observe the possible protective effects of resveratrol (RSV) against the damage of di-n-butyl phthalate (DBP) on the testis. The study was conducted in 6 groups of rats with 6 animals in each group aged 20 days. The groups include group 1: control group; group 2: solvent (carboxymethylcellulose (CMC), 10 ml/kg); group 3: 500 mg/kg/day DBP; group 4: 500 mg/kg/day DBP + 20 mg/kg/day RSV; group 5: 1000 mg/kg/day DBP; and group 6: 1000 mg/kg/day DBP + 20 mg/kg/day RSV. Groups were treated by gavage for 30 days. Indirect immunohistochemical staining was performed with c-kit, AT1, and ER-α antibodies. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling (TUNEL) method was used for apoptosis. It was found in the DBP-applied groups the C-kit immunostaining, which is parallel to increasing dose, decreased in comparison with the control. C-kit reactivity was similar to that of the control group in the group applied with 500 mg/kg/day + RSV; however, the reactivity was not same in the 1000 mg/kg/day DBP-applied group. It was observed that the reactivity of AT1 increased in the DBP-applied groups. RSV reversed these changes with its protective effects. While there was not much difference between the groups in terms of estrogen receptor reactivity, it was observed that the high dose of DBP reduced the level of estrogen receptor and the resveratrol was not at enough levels in all doses. In TUNEL analysis, high doses of DBP increased the apoptosis in all types of cells; nevertheless, the resveratrol application decreased the apoptosis in the low-level DBP dose. In the statistical analysis, while the length of epithelium and the diameter of seminiferous tubules decreased for all the other groups, it reverted to its original state in the RSV-applied groups. In conclusion, DBP (with increasing dose) administration caused cycle and hormonal changes in testis, resveratrol were recovered the cyclic changes but in hormonal changes, RSV is efficient too but inadequate.

Ciliary body toxicities of systemic oxcarbazepine and valproic acid treatments: electron microscopic study.

Ciliary body is responsible for humour aqueous production in posterior chamber. Valproic acid (VPA) has been widely used for the treatment of epilepsy and other neuropsychiatric diseases such as bipolar disease and major depression. Oxcarbazepine (OXC) is a new anti-epileptic agent that has been used recently for childhood epilepsies such as VPA. In this study, we aimed to investigate the effects of VPA and OXC treatments used as antiepileptic in ciliary body by electron microscopy. In our study, 40 Wistar rats (21 days old) were divided equally into four groups which were applied saline (group 1), VPA (group 2), OXC (group 3) and VPA + OXC (group 4). The as-prepared ocular tissues were characterized by transmission electron microscopy (TEM) technique in scanning and transmission electron microscopy (SEM-TEM) (Carl Zeiss EVO LS10). The results confirmed that VPA caused dense ciliary body degeneration. Additionally, ciliary body degeneration in group 4 was supposed to be due to VPA treatment. Ciliary body damage and secondary outcomes should be considered in patients with long-term VPA therapy.

Effects of hyperglycemia on the developing brain in newborns.

BACKGROUND: Hyperglycemia is a common problem in preterm neonates and is associated with increased risk of mortality and severe morbidities such as brain damage. However, available data about the effects of severity of hyperglycemia on the developing brain in the early life is limited. Therefore, we evaluated the effects of moderate and severe hyperglycemia on the developing brain. METHOD: Thirty newborn Sprague-Dawley rats were randomly divided into three groups as control, moderate hyperglycemia (30% dextrose), and severe hyperglycemia (50% dextrose). Pups in the hyperglycemia groups were administered subcutaneous sterile dextrose solution at a dose of 4 mL/kg daily from the second day to the eleventh day of life. Blood glucose levels were measured every day in all study groups. Rat brain tissues were removed at the end of the study. Histopathologic and immunohistochemical (caspase-9, -8, and -3) examination and biochemical analysis including xanthine oxidase, total antioxidant status, total oxidant status, and malondialdehyde activities were performed. RESULTS: Weight of the brain tissues in rats with hyperglycemia groups was significantly lower than the control group (P < 0.05). Weight of the brain tissues in rats with moderate hyperglycemia was lower than that of the severe hyperglycemia (P < 0.05). In the histopathologic and immunochemical evaluation, severity of brain damage and apoptosis were significantly higher in the severe hyperglycemia group, especially at the level of the hippocampus (P < 0.05). Tissue malondialdehyde, xanthine oxidase levels, and total oxidant status were significantly increased in the severe hyperglycemia group, whereas total antioxidant status was significantly decreased in the severe hyperglycemia group (P < 0.001). CONCLUSION: Brain damaging effects of severe hyperglycemia were observed in the developing brains of the rat pups. It might be inferred that severe hyperglycemia can damage the developing brain especially in preterm infants.

Protective effects of resveratrol against di-n buthyl phthalate induced toxicity in ductus epididymis and ductus deferens in rats.

OBJECTIVE: This study aimed to observe the possible protective effects of resveratrol (RSV) against damage induced by di-n-butylphthalate (DBP), on the ductus epididymis and deferens in rats. MATERIALS AND METHODS: Six groups of rats were used in the experiment: Group 1: Control group; Group 2: Solvent (carboxymethylcellulose (CMC), 10 ml/kg); Group 3: 500 mg/kg/day DBP; Group 4: 500 mg/kg/day DBP+20 mg/kg/day RSV; Group 5: 1000 mg/kg/day DBP; Group 6: 1000 mg/kg/day DBP + 20 mg/kg/day RSV. Groups were treated by gavage for 30 days. Immunohistochemical, electronmicroscopic and histomorphometric examinations were carried out in the epididymis and deferens. RESULTS: In the ductus epididymis and deferens mitochondrial crystolysis, exfoliation of the stereocilia and openings in lateral surface increased with DBP dosage, but these structures were recovered with RSV. DBP reduced the epithelial height of epididymis and vas deferens. Lumen dilatation was observed in both tissues. These disorders may lead to dysfunction of epithelial absorption. In the TUNEL examinations in both tissues, there were no apoptotic cells or apoptotic bodies. CONCLUSION: In conclusion, DBP administration caused structural degeneration in the epididymis and deferens, parallel to dose evaluation and RSV can reverse these changes with its protective effects.

Comparison of hippocampal interleukin-6 immunoreactivity after exhaustive exercise in both exercise-trained and untrained rats.

BACKGROUND/AIM: Exhaustive exercise is a strong stress factor and can impact cytokine production in the brain. Interleukin-6 (IL-6) is produced in greater amounts than any other cytokine in response to exercise, and its effects are closely related to both exercise duration and intensity. In this study, we measured the differences between the amount of IL-6 reactivity of the hippocampus after an exhaustive session ofrunning in long-term exercise-trained and untrained rats. MATERIALS AND METHODS: The exercise-trained group ran on a treadmill for 12 weeks. Both groups were forced to run until exhaustion. Each group of rats was sacrificed immediately, 1 day, or 3 days after exhaustion and the brains were evaluated for IL-6 immunoreactivity in the hippocampus. RESULTS: Hippocampal IL-6 immunoreactivity was absent in controls, mild to severe in untrained rats, and weak to mild in long-term-trained rats. The most prominent increase in IL-6 was observed in the untrained rats sacrificed 1 day after exhaustion. CONCLUSION: Exercise to exhaustion resulted in increased IL-6 levels in brain slices in both groups of rats, but long-term exercise training protected the hippocampus from exposure to an extreme increase in IL-6. The immediate effects of these cytokine levels were observed 1 day after exhaustion.

Transmission and scanning electron microscopy confirm that bone microstructure is similar in osteopenic and osteoporotic patients.

OBJECTIVES: The objective was to confirm the finding of "Bone microstructure is similar in osteopenic and osteoporotic patients with femoral neck fracture." obtained in previous "light microscopy study", which was new and important data. PATIENTS AND METHODS: Fourteen patients (5 males, 9 females) who were admitted with proximal femoral fracture following low energy trauma (patients who participated in the light microscopy study) were included. The patients were divided into two groups based on the bone mineral density (BMD) measurement, including osteopenic group (n=7, mean age 69 years; range 63 to 74 years) and osteoporotic group (n=7, mean age 74.1 years; range 67 to 78 years). Cortical and trabecular bone samples were taken from the patients who underwent endoprosthesis during partial hip arthroplasty and these samples were analyzed using transmission electron microscopy and scanning electron microscopy evaluations which are more sophisticated higher resolution techniques. RESULTS: The mean cortical bone thickness was 3622.14 mm in osteopenic group and 2323.14 mm in osteoporotic group (p<0.005). Transmission electron microscopy and scanning electron microscopy evaluations revealed similar findings for both groups. CONCLUSION: Although a significant difference in cortical thickness was found between the groups, transmission and scanning electron microscopy confirmed that bone microstructure shared similar characteristics in osteopenic and osteoporotic patients with low-energy femoral neck fracture, as it was in previous light microscopy study.

The treatment of segmental bone defects in rabbit tibiae with vascular endothelial growth factor (VEGF)-loaded gelatin/hydroxyapatite "cryogel" scaffold.

The aim of this study was to investigate the effectiveness of a novel hydroxyapatite containing gelatin scaffold--with and without local vascular endothelial growth factor (VEGF) administration--as the synthetic graft material in treatment of critical-sized bone defects. An experimental nonunion model was established by creating critical-sized (10 mm. in length) bone defects in the proximal tibiae of 30 skeletally mature New Zealand white rabbits. Following tibial intramedullary fixation, the rabbits were grouped into three: The defects were left empty in the first (control) group, the defects were grafted with synthetic scaffolds in the second group, and synthetic scaffolds loaded with VEGF were administered at bone defects in the third group. Five rabbits in each group were killed on 6th and 12th weeks, and new bone growth was assessed radiologically, histologically and with dual-energy X-ray absorptiometry (DEXA). At 6 weeks, VEGF-administered group had significantly better scores than the other two groups. The second group also had significantly better scores than the control group. At 12 weeks, while no significant difference was noted between the second and third groups, these two groups both had significantly better scores in all criteria compared with the control group. There were no signs of complete fracture healing in the control group. The administration of hydroxyapatite containing gelatin scaffold yielded favorable results in grafting the critical-sized bone defects in this experimental model. The local administration of VEGF on the graft had a positive effect in the early phase of fracture healing.

[Is bone microstructure different between osteopenic and osteoporotic patients with femoral neck fracture?]. / Femur boyun kirigi olan osteopenik ve osteoporotik hastalarda kemik mikromimarisi farkli midir?

OBJECTIVES: This study aims to investigate whether bone microstructure is different between osteopenic and osteoporotic patients with femoral neck fracture. PATIENTS AND METHODS: Fourteen patients (5 males, 9 females) with proximal femoral fracture following low energy trauma were included in the study. Patients with secondary osteoporosis and who received antiosteoporotic treatment prior to trauma were excluded. The patients were divided into two groups based on the bone mineral density measurement, including osteopenic group (n=7, mean age 69 years; range 63-74 years) and osteoporotic group (n=7, mean age 74.1 years; range 67-78 years). Cortical bone specimens for biopsy obtained from the patients who underwent endoprosthesis during partial hip arthroplasty and were evaluated using light microscope. RESULTS: Mean cortical bone thickness was 3622.14 µM in osteopenic group, and 2323.14 µM in osteoporotic group (p<0.005). However, light microscope revealed similar characteristics for both groups. CONCLUSION: Although a significant difference was found between the groups in terms of cortical thickness, bone microstructure showed similar characteristics in osteopenic and osteoporotic patients with low energy femoral neck fracture.

Could nephrotoxicity due to colistin be ameliorated with the use of N-acetylcysteine?

PURPOSE: The protective effect of N-acetylcysteine (NAC) on nephrotoxicity due to contrast nephropathy and reperfusion-induced ischemia has been reported in experimental models. However, its efficacy on colistin-induced nephrotoxicity has not been elucidated yet. The primary aim of this study was to evaluate the nephrotoxic effect of colistin and to investigate the possible protective effect of NAC on colistin-induced nephrotoxicity. The secondary aim was to research the systemic effects of nephrotoxicity-induced oxidative stress on the lung. METHODS: Eighteen female Sprague-Dawley rats were randomly assigned and were given (a) 1 ml/kg sterile saline, (b) 300,000 IU/kg/day colistin, and (c) 300,000 IU/kg/day colistin and 150 mg/kg NAC for six consecutive days. RESULTS: Plasma blood urea nitrogen (BUN), creatinine, urinary creatinine, urinary protein, plasma TNF-alpha levels, renal tissue superoxide dismutase (SOD) and malondialdehyde (MDA) activity and immunocytochemical findings were evaluated. Colistin exerted nephrotoxicity and achieved a significant increase in plasma BUN and creatinine levels and renal tissue SOD levels. NAC exhibited no significant effect on biochemical parameters but reduced renal tissue SOD level and reversed immunocytochemical staining of inducible nitric oxide synthase (i-NOS) and neurotrophin-3. Increased oxidative stress in the lung tissue of the rats treated with colistin has also been documented. Additionally, NAC significantly reduced the immunostaining of endothelial NOS (e-NOS) and i-NOS in the lung tissue. CONCLUSIONS: Colistin-induced renal toxicity may be attributable to oxidative damage. The combined treatment of colistin plus NAC seems to have a beneficial role in restoration of the oxidant injury which may be related to its antioxidant effect.

[Age-related changes in light microscopy with Sirius red technique in rat Achilles tendon]. / Siçan Asil tendonunda yasa bagli degisikliklerin isik mikroskobunda Sirius kirmizi teknigi ile incelenmesi.

OBJECTIVES: In this study, age-related morphological changes in intact rat Achilles tendon was investigated. MATERIALS AND METHODS: Thirty Wistar albino rats of 2-3 weeks, six months and 12 months old groups 10 animal in each group were examined with Sirius red light microscobic staining. RESULTS: The Sirius red light microscobic staining revealed that red stained collagen fibers have a decreased waviness with more rounded appearence of tenocyte nuclei, extracellular matrix along a increased vascularity and the number of tenocytes decreased with age was statistically meaningfull. CONCLUSION: The possible causes of the spontaneously Achilles tendon rupture in adult ages group was investigated with Sirius red light microscopic technique. In this age group, initiation of the degenerative changes are decreasing the elasticity thus function of this tendon.

Trauma does not aggravate deleterious effects of ischemia reperfusion injury on the lung.

OBJECTIVES: Our purpose was to investigate the effects of ischemia-reperfusion injury on traumatized lungs. MATERIALS AND METHODS: Twenty-four Wistar rats were used in the study. Rats were randomly divided into 4 groups. In the control group (group 1), only anesthesia and ventilation were used. In group 2, only lung ischemia-reperfusion injury was instituted. In group 3, only blunt chest trauma was instituted. And in group 4, lung ischemia reperfusion injury, consisting of 24 hours after the constitution of blunt chest trauma, was used. Lung damage and systemic inflammation parameters were evaluated. RESULTS: All parameters (alveolar degeneration grades, alveolar macrophage and lymphocyte counts, antioxidant enzyme activities, cytokine levels, and bronchoalveolar lavage fluid albumin level) were higher in all groups than they were in the control group (P < .05). Only tissue malondialdehyde, tissue interleukin-8, and serum glutathione peroxidase levels were significantly higher in the lung ischemia-reperfusion group than they were in the trauma group (P < .05). The trauma + ischemia reperfusion group showed no significant difference when compared with the only ischemia-reperfusion or only trauma groups in any parameters (P > .05). CONCLUSIONS: The findings showed that lung trauma does not aggravate the deleterious effects of lung ischemia-reperfusion injury.

Retinal ganglion cell toxicity due to oxcarbazepine and valproic acid treatment in rat.

PURPOSE: To evaluate and to compare the possible toxic effects of oxcarbazepine (OXC) and valproic acid (VPA) on retinal ganglion cells (RGCs) in rat. METHODS: Forty female Wistar rats (21-24 days old and weighted between 44.6 and 57.3g) were divided equally into 4 experimental groups which were applied tap water (group 1), 300mg/(kgday) VPA (group 2), 100mg/(kgday) OXC (group 3), and both VPA and OXC (group 4) via gavage for 90 days. Enucleation was performed for histopathologic analysis. RGCs were counted under the light microscopic examination. RESULTS: RGC numbers in OXC and combined OXC-VPA groups were found to be lower than those of control group. On the other hand RGC number was comparable with those of control group in VPA group. CONCLUSION: OXC seems to be toxic to RGCs at 100mg/kg dose when it is been given as a monotherapy or combined with VPA. Single VPA treatment has no effect on RGC number.