Murat Yagmurca

The protective effect of fish n-3 fatty acids on cerebral ischemia in rat hippocampus

Reactive oxygen species (ROS) have been implicated in the pathogenesis of cerebral injury after ischemia-reperfusion (I/R). Fish n-3 essential fatty acids (EFA), contain eicosapentaenoic acids (EPA) and docosahexoenoic acids (DHA), exhibit antioxidant properties. DHA is an important component of brain membrane phospholipids and is necessary for the continuity of neuronal functions. EPA prevents platelet aggregation and inhibits the conversion of arachidonic acid into thromboxane A(2) and prostaglandins. They have been suggested to be protective agents against neurological and neuropsychiatric disorders. In this study, the neuroprotective effects of fish n-3 EFA on oxidant-antioxidant systems and number of apoptotic neurons of the hippocampal formation (HF) subjected to cerebral I/R injury was investigated in Sprague-Dawley rats. Six rats were used as control (Group I). Cerebral ischemia was produced by occlusion of both the common carotid arteries combined with hypotension for 45 min, followed by reperfusion for 30 min, in rats either on a standard diet (Group II) or a standard diet plus fish n-3 EFA (Marincap((R)), 0.4 g/kg/day, by gavage) for 14 days (Group III). At the end of procedures, the rats were sacrificed and their brains were removed immediately. The levels of malonedialdehyde (MDA) and nitric oxide (NO) and activities of superoxide dismutase (SOD) and catalase (CAT) were measured in left HF. In addition, the number of apoptotic neurons was counted by terminal transferase dUTP nick end labelling (TUNEL) assay in histological samples of the right HF. We found that SOD activities and MDA levels increased in Group III rats compared with Group II rats. On the other hand, CAT activities and NO levels were found to be decreased in Group III rats compared with Group II rats. Additionally, the number of apoptotic neurons was lower in Group III in comparison with Group II rats. The present findings suggest that fish n-3 EFA could decrease the oxidative status and apoptotic changes in ischemic rat hippocampal formation. Dietary supplementation of n-3 EFA may be beneficial to preserve or ameliorate ischemic cerebral vascular disease.

Erdosteine prevents doxorubicin-induced cardiotoxicity in rats.

The clinical use of doxorubicin (Dxr) is limited by its cardiotoxic effects which are mediated by oxygen radicals. The purpose of this study was to investigate in vivo protective effects of erdosteine, an antioxidant agent because of its secondary active metabolites in vivo, against the cardiotoxicity induced by Dxr in rats. Three groups of male Sprague-Dawley rats (60 days old) were used. Group 1 was untreated group used as control; the other groups were treated with Dxr (single i.p. dosage of 20 mg kg(-1) b.wt.) or Dxr plus erdosteine (10 mg kg(-1) day(-1), orally), respectively. Erdosteine or oral saline treatment was done starting 2 days before Dxr for 12 days. The analyses were done at the 10th day of Dxr treatment. The protein carbonyl content, the activities of myeloperoxidase, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and creatine kinase (CK) as well as heart rate and blood pressures were significantly increased in Dxr group in comparison with the other groups. However, pulse pressure was decreased in Dxr group. The body and heart weights were decreased in both Dxr administered groups in comparison with control group. Disorganization of myocardial histology, picnotic nuclei, edema, and increase in collagen content around vessels were seen in the slides of Dxr group, whereas normal myocardial microscopy was preserved in Dxr plus erdosteine group. Collectively, these in vivo hemodynamic, enzymatic and morphologic studies provide an evidence for a possible prevention of cardiac toxicity in Dxr-treated patients.

The neuroprotective effect of dexmedetomidine in the hippocampus of rabbits after subarachnoid hemorrhage.

BACKGROUND Subarachnoid hemorrhage is a serious condition, often accompanied by cerebral vasospasm, which may lead to brain ischemia and neurologic deterioration. We evaluated if dexmedetomidine has neuroprotective effects in the hippocampus of vasospastic SAH rabbits or not. MATERIALS AND METHODS Eighteen New Zealand rabbits were taken. An experimental SAH model was formed by injecting 0.9 mL of autologous arterial blood per 1 kg of body weight to the cisterna magna of 12 rabbits. Craniotomy was performed in the control group (n = 6) except performing experimental SAH. Rabbits in the SAH-alone (n = 6) group were infused with 5 mL.kg(-1).h(-1) 0.9% sodium chloride, and rabbits (n = 6) in the SAH-dexmedetomidine group were infused with 5 microg.kg(-1).h(-1) dexmedetomidine for 2 hours, 48 hours after SAH was established. Rabbits of all groups were sacrificed via penthotal 24 hours after dexmedetomidine administration. Brains were removed immediately, and hippocampal tissues were blocked from the right hemisphere for histopathologic study. In addition to this, hippocampal tissues of left hemispheres were dissected for biochemical analyses to evaluate MDA levels, activity of XO, and SOD. RESULTS The histopathologic study showed that dexmedetomidine may have a neuroprotective effect in SAH-induced hippocampal injuries. The biochemical parameters support the neuroprotective effect of dexmedetomidine (P < .05). CONCLUSION Our study showed that dexmedetomidine may have a neuroprotective effect in the hippocampus of vasospastic SAH rabbits.

Preventive effect of melatonin on bleomycin-induced lung fibrosis in rats

Abstract:  Oxidative stress has an important role in the pathogenesis of idiopathic pulmonary fibrosis. Melatonin has direct and indirect free radical‐detoxifying activity. The present study investigated whether melatonin treatment attenuates bleomycin‐induced lung fibrosis in rats. A group of rats was given one dose of bleomycin while the control animals were given saline. The first dose of melatonin (4 mg/kg/day) was given 2 days before the bleomycin injection. At day 14, fibrotic changes were evaluated using Aschofts criteria and lung hydroxyproline content. Bleomycin produced a 2.7‐fold rise in the fibrosis score that was decreased 65% by melatonin (P < 0.05) and a 1.4‐fold increase in hydroxyproline content which was completely prevented by melatonin. Protein carbonyl and thiobarbituric acid reactive substances levels, which were significantly elevated in the bleomycin treated rats, were significantly attenuated by melatonin. Bleomycin administration significantly reduced the activities of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px) in lung tissue. The reduction in CAT activity was prevented by melatonin but SOD and GSH‐Px were not influenced. These results revealed that melatonin may prevent the development of bleomycin‐induced lung fibrosis via the repression of protein and lipid peroxidation.

Effects of formaldehyde exposure on granule cell number and volume of dentate gyrus: a histopathological and stereological study.

The hippocampal formation is a complex region of the brain related to memory and learning. The purpose of the present study was to determine whether exposure of neonatal rats to formaldehyde (FA) had either early or delayed effects on the numbers of granule cells in the dentate gyrus (DG). After birth, the neonatal male Wistar rats were exposed throughout a 30-day period to various concentrations of FA: 0 (control group), 6 ppm (low concentration group) and 12 ppm (high concentration group). This was done by placing them for 6 h/day and 5 days per week in a glass chamber containing FA vapor. Then, five animals from each group were anesthetized and decapitated on postnatal day (PND) 30, and the remaining five animals were sacrificed on PND 90 by intracardiac perfusion using 10% neutral buffered FA solution. The Cavalieri principle of stereological approaches was used to determine the volume of the DG in these sections. The optical fractionator counting method was used to estimate the total number of granule cells in the DG. The appearance of granule cells was normal under light microscopy in all PND 30 and PND 90 groups. There were significant age-related reductions in the volume of the DG at PND 90 irrespective of which group was examined. Significant age-related neuron loss was also determined at PND 90 compared to that at PND 30. Rats treated with a high concentration FA were found to have fewer granule cells than either the animals treated with a low concentration FA or the control group (p<0.01 and p<0.01, respectively) at PND 90 but not at PND 30. These findings clearly indicate that granule cells in the DG may be vulnerable to stress and the concentration of FA to which they are exposed during early postnatal life, and also that a neurotoxic effect of high dose FA on cell number is only seen after a long time period. These results may explain why some disorders do not appear until later life.

Effects of electromagnetic radiation from a cellular telephone on epidermal Merkel cells

The number of reports on the effects induced by electromagnetic radiation (EMR) from cellular telephones in various cellular systems is still increasing. Until now, no satisfactory mechanism has been proposed to explain the biological effects of this radiation except a role suggested for mast cells. Merkel cells may also play a role in the mechanisms of biological effects of EMR. This study was undertaken to investigate the influence of EMR from a cellular telephone (900 MHz) on Merkel cells in rats. A group of rats was exposed to a cellular telephone in speech position for 30 min. Another group of rats was sham‐exposed under the same environmental conditions for 30 min. Exposure led to significantly higher exocytotic activity in Merkel cells compared with the sham exposure group. This finding may indicate the possible role of Merkel cells in the pathophysiology of the effects of EMR.

The neuroprotective effect of fish n-3 fatty acids in the hippocampus of diabetic rats

Abstract Introduction: Diabetes mellitus may lead to functional and structural changes in the brain. Fish oil is a rich source of n-3 essential fatty acids (EFA) such as eicosapentaenoic and docosahexoenoic acids. We examined the neuroprotective effects of fish n-3 EFA in the hippocampus of diabetic rats. Materials and methods: Nineteen adult male rats were divided into three groups. Group I (control; n = 6) was fed a normal rat diet. Group II (diabetic; n = 6) was fed a normal rat diet and streptozotocin (STZ) was administered to induce diabetes mellitus. Group III (n-3 + diabetic; n = 7) was fed a normal rat diet and fish n-3 EFA (Marincap®, 0.4 g/kg/day) for 8 weeks and STZ was administered to induce diabetes mellitus. The levels of malondialdehyde (MDA) and activities of superoxide dismutase (SOD) and catalase (CAT) were measured in the left hippocampus after the animals were sacrificed. The right hemisphere was completely blocked. The sections were stained with Cresyl Violet and apoptotic neurons were counted in the hippocampus. Results: The levels of MDA and activities of SOD and CAT increased in diabetic rats compared to control rats. However, the levels of MDA and activities of SOD and CAT decreased in n-3 + diabetic rats compared to diabetic rats. Also, the number of apoptotic neurons increased in diabetic rats compared to control rats and decreased in n-3 + diabetic rats compared to diabetic rats. Conclusions: Fish n-3 EFA reduces oxidative stress and induces apoptotic changes in the hippocampus of STZ-diabetic rats. The addition of fish n-3 EFA to diets may be useful to prevent functional and structural changes to cerebral centers due to diabetes mellitus.

Novel approach for the prevention of contrast nephropathy

OBJECTIVE To date, there is no effective treatment of contrast medium (CM)-induced nephropathy. Multiple studies documented a protective role of hydration and N-acetylcystein (NAC) as prophylactic agents against CM-induced nephropathy in a high-risk population. In the present study, we investigated a new antioxidant agent, caffeic acid phenethyl ester (CAPE), and compare with NAC against contrast nephropathy. METHODS Forty-two adult male rats were divided into six experimental groups, which were control, injected with intravenous (i.v.) CM, injected with i.p. CAPE, injected with i.p. NAC, injected with i.v. CM pretreated with i.p. CAPE, injected with i.v. CM pretreated with i.p. NAC. CAPE and NAC were given daily throughout the study. All rats were deprived of water for 24h at the third day of the study and then contrast medium was administered to CM, CAPECM and NACCM groups. The rats were sacrificed at the fifth day. Oxidant-antioxidant status was determined in renal tissues. The severity of injury was scored with a light microscope in renal tissue. Plasma creatinine levels were measured. RESULTS Renal injury scores were higher in CAPECM and NACCM groups than in control, CAPE and NAC groups, but lower than the CM group. Likewise, creatinine levels of CAPECM and NACCM groups were higher than the control groups but they were significantly lower than the level of the CM group. Creatinine levels of the NACCM group were significantly higher than the CAPECM group. Malondialdehyde levels were significantly lower in CAPECM and NACCM groups than the CM group. CONCLUSION CAPE might protect renal structure and functions as well as NAC against CM injury.

Protective Effect of Alpha Lipoic Acid on Rat Sciatic Nerve Ischemia Reperfusion Damage.

BACKGROUND Alpha lipoic acid is a potent antioxidant that plays numerous roles in human health. This study examined the effect of ALA on rat sciatic nerve ischemia reperfusion damage. AIMS Protective effect of alpha lipoic acid (ALA) on sciatic nerve following ischemia-reperfusion in rats was investigated by using light microscopy and biochemical methods. Provided that the protective effect of ALA on sciatic nerve is proven, we think the damage to the sciatic nerve that has already occurred or might occur in patients for various reasons maybe prevented or stopped by giving ALA in convenient doses. STUDY DESIGN Animal experiment. METHODS Forty-two adult male Sprague-Dawley rats (250-300 grams) were used in this study. Rats were randomly divided into six groups including one control (Group 1), one sham (Group 2), two ischemia-reperfusion (Groups 3 and 4) and two treatment groups (Groups5 and 6). Doses of 60 and 100 mg/kg ALA were given (Group 5 and 6) intra peritoneally twice, 1 and 24 hours before the ischemia to each treatment group. Ischemia was carried out the abdominal aorta starting from the distal part of the renal vein for two hours followed by reperfusion for three hours. In immunohistochemical methods, fibronectin immunoreactivity was analyzed. For biochemical analyses, the tissues were taken in eppendorf microtubes and superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) enzyme activities as well as malondialdehyde (MDA) and nitricoxide (NO) levels were measured. RESULTS Fibronectin was observed to have increased significantly in the ischemia group; on the other hand, it was observed to have decreased in parallel to the doses in the ALA groups. Biochemical studies showed that SOD and GSHPx declined with ischemia-reperfusion, but the activities of these enzymes were increased in the treatment groups in parallel with the dose. It was found that increased MDA levels with ischemia-reperfusion were decreased in parallel with ALA dose. There were no statistically significant changes in NO. CONCLUSION Increased fibronectin observed after ischemia/reperfusion of rat sciatic nerve is reduced after the administration of ALA. This indicates that the function of fibronectin, to reconnect cut nerve segments and regenerate nerves, is more prominent than its function in tissue healing after ischemia. ALA administered before ischemia decreases MDA and increases SOD and GSHPx. We think that ALA may protect against the pathological changes in ischemic nerve and may be used to devise more efficient treatments.

Histological assessment of skin grafts stored in amniotic fluid and saline

Abstract We investigated the efficacy of amniotic fluid as a substance in which to store grafts; it is rich in nutrients, proteins, and growth factors, and has well-known antimicrobial features. We compared it with the widely-used and practical saline. Split-thickness grafts 4 × 4 cm were prepared from the back of 20 rats and divided into four groups (n = 5 each). The rolled grafts were wrapped in gauze dampened with saline or amniotic fluid and placed into refrigerators in sterile containers for storage. On days 7, 14, 21, and 28, histological examinations were made. A semiquantitative evaluation of the histological damage to the skin was made by scoring its degree of severity. Compared with saline, histological scores in the grafts stored in amniotic fluid were found to be significantly lower on the 14th, 21st, and 28th days (p values on days 14, 21, and 28; cell swelling: 0.014, 0.006, and 0.005, respectively; nuclear swelling: 0.003, 0.006, and 0.007, respectively; nuclear pleomorphism: 0.004, 0.005, and 0.003, respectively; nuclear haloes: 0.015, 0.005, and 0.005, respectively; nuclear pyknosis: 0.003, 0.005, and 0.003, respectively; dermo-epidermal clefting: 0.005, 0.003, and 0.003, respectively; eosinophilia and mitosis: 0.003, 0.006, and 0.004, respectively; dermal collagen: 0.003, 0.003, and 0.003, respectively). Amniotic fluid maintained preservation better for skin grafts than saline. Comparison with other modern storage media would be beneficial.