Ilter Kus

The protective effects of omega − 3 fatty acids against MK-801-induced neurotoxicity in prefrontal cortex of rat

The aims of this study are to investigate the contribution effect of oxidative stress in MK-801-induced experimental psychosis model, and to show that prevention of oxidative stress may improve prognosis. Because oxidative damage has been suggested in the neuropathophysiology of schizophrenia, the possible protecting agents against lipid peroxidation are potential target for the studies in this field. For this purpose, Wistar Albino rats were divided into three groups: the first group was used as control, MK-801 was given to the rats in the second group and MK-801+omega-3 essential fatty acids (EFA) was given to the third group. MK-801 was given intraperitoneally at the dose of 0.5mg/(kgday) once a day for 5 days in experimental psychosis group. In the second group, 0.8g/(kgday), omega-3 FA (eicosapentaenoic acid, 18%, docosahexaenoic acid, 12%) was given to the rats while exposed MK-801. In control group, saline was given intraperitoneally at the same time. After 7 days, rats were killed by decapitation. Prefrontal brain area was removed for histological and biochemical analyses. As a result, malondialdehyde (MDA), as an indicator of lipid peroxidation, protein carbonyl (PC), as an indicator of protein oxidation, nitric oxide (NO) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities as antioxidant enzymes, and xanthine oxidase (XO) and adenosine deaminase (AD) activities as an indicator of DNA oxidation was found to be increased significantly in prefrontal cortex (PFC) of MK-801 group (P<0.0001) compared to control group. In omega-3 FA treated rats, prefrontal tissue MDA, PC and NO levels as well as SOD, GSH-Px, XO, and AD enzyme activities were significantly decreased when compared to MK-801 groups (P<0.0001) whereas catalase (CAT) enzyme activity was not changed. Moreover, in the light of microscopic examination of MK-801 groups, a great number of apoptotic cells were observed. omega-3 FA supplementation decreased the apoptotic cell count in PFC. The results of this study revealed that oxidative stress and apoptotic changes in PFC may play an important role in the pathogenesis of MK-801-induced neuronal toxicity. This experimental study also provides some evidences for the protective effects of omega-3 FA on MK-801-induced changes in PFC of rats.

Effect of formaldehyde inhalation on Hsp70 in seminiferous tubules of rat testes: an immunohistochemical study

One parameter which might provide an insight into the underlying mechanism of the effect of formaldehyde (FA) inhalation on testicular tissue, is the assessment of heat shock protein 70 (Hsp70), which increases promptly in cells exposed to stress caused by chemical toxicity. Thus, following subchronic exposure at cytotoxic concentrations, we studied the immunohistochemical effect of FA inhalation on changes in Hsp70 content in testicular tissue. We used 18 albino Wistar rats divided into three groups, exposed to 0 (control), 5 and 10 ppm FA gas for a total of 91 days, 8 h/day, five days a week. Serum testosterone levels were determined using a chemiluminescent enzyme immunoassay. Testicular tissues were stained with Hematoxylin-Eosine and Hsp70 immunohistochemically performed. Diameters of seminiferous tubules and serum testosterone levels in animals inhaling FA were significantly decreased. In seminiferous epithelium stained for Hsp70, compared to those in the control group, the spermatogenetic cells in the experimental groups demonstrated an obvious increase in immunoreaction spermatides in the adluminal region and especially in the cytoplasm of spermatocytes. Immunoreaction of Hsp70 was detected in the spermatogonias of animals exposed to FA inhalation as opposed to those of the control group. Compared to the control, there was a significant increase in the immunoreactions observed not only in the cytoplasm of primary spermatocytes, but also spermatides in the adluminal region of the seminiferous tubules. In conclusion, FA gas may damage spermatogenetic cells and increase Hsp70 synthesis.

Testicular zinc, copper and iron concentrations in male rats exposed to subacute and subchronic formaldehyde gas inhalation

The level of trace elements such as Zn, Cu and Fe in testicular tissue is an indication of the condition of the tissue as these elements take over important tasks. Zinc and copper are the prosthetic groups of several metalloenzymes including superoxide dismutase (SOD) which is an important antioxidant enzyme in the cellular protection from reactive oxygen species. If concentrations of these trace elements decrease significantly, SOD cannot detoxify harmful oxygen species. In this study, adult male rats (wistar-albino) were exposed to formaldehyde at different periods (subacute and subchronic) and concentrations (0; 12.2; 24.4 mg.L-1). Body and testis weights were recorded and compared with control groups. The metals described above were determined in rat testicular tissue by atomic absorption spectrometry by using wet ashing. We conclude that subacute or subchronic exposure to formaldehyde have caused growth retardation and altered levels of trace elements, including copper, zinc and iron, in testicular tissue, and may induce further oxidative damage on testicular tissue leading to spermatozoal abnormalities.

Effects of v-3 essential fatty acids against formaldehyde-induced nephropathy in rats:

The aim of this study was to examine the toxicity of formaldehyde (FA) on the kidney and the protective effects of v-3 essential fatty acids against these toxic effects. Twenty-one male Wistar rats were divided into three groups. Rats in Group I comprised the controls, while the rats in Group II were injected every other day with FA. Rats in Group III received v-3 fatty acids daily while exposed to FA. At the end of the 14-day experimental period, all rats were killed by decapitation and the kidneys removed. Some of the kidney tissue specimens were used for determination of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities, and malondialdehyde (MDA) levels. The remaining kidney tissue specimens were used for light microscopic evaluation. The levels of SOD and GSH-Px were significantly decreased, and MDA levels were significantly increased in rats treated with FA compared with those of the controls. Furthermore, in the microscopic examination of this group, glomerular and tubular degeneration, vascular congestion and tubular dilatation were observed. However, increased SOD and GSH-Px enzyme activities, and decreased MDA levels were detected in the rats administered v-3 fatty acids while exposed to FA. Additionally, kidney damage caused by FA was decreased and structural appearance was similar to that of the control rats in this group. In conclusion, it was determined that FA-induced kidney damage was prevented by administration of v-3 essential fatty acids.

Protective effects of melatonin against formaldehyde-induced oxidative damage and apoptosis in rat testes: an immunohistochemical and biochemical study.

This study investigated the protective effects of melatonin against formaldehyde-induced oxidative damage and apoptosis in rat testes. A total of 21 male Wistar rats were divided into three groups. Group I was used as a control, Group II was injected every other day with formaldehyde for 1 month, whereas Group III was injected every other day with formaldehyde and melatonin for 1 month. At the end of the experimental period animals were sacrificed and the testes removed and dissected from the surrounding tissues for immunohistochemical evaluation. In addition, the levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were determined. The levels of SOD and GSH-Px decreased significantly, whereas the level of MDA significantly increased in animals treated with formaldehyde compared with the controls. Apoptosis of spermatogenetic and Leydig cells of testicular tissues was observed. In contrast, rats with melatonin SOD and GSH-Px enzyme activity increased whereas MDA levels decreased with formaldehyde exposure along with apoptosis. In view of the present findings, it is suggested that melatonin treatment may prevent formaldehyde-induced oxidative damage and apoptosis in rat testes.

ULTRASTRUCTURAL INTERRELATIONSHIP BETWEEN THE PINEAL GLAND AND THE TESTIS IN THE MALE RAT

The ultrastructural interrelationship between the pineal gland and testis was evaluated in the rat. Wistar rats were divided into 6 groups. Groups I and II were sham-orchidectomized and orchidectomized rats, respectively. Rats in group III were orchidectomized and daily injected with testosterone propionate (TP) for 1 month. Groups IV and V were sham-pinealectomized and pinealectomized, respectively. Group VI was pinealectomized and daily injected with melatonin for 2 months. All animals were anesthetized with ketamine for fixation by vascular perfusion. Pineal glands of groups I, II, and III and the testes of groups IV, V, and VI were removed and weighed. All specimens were examined by electron microscopy. Orchidectomy caused an increase of lipid droplets, cytoplasmic dense bodies, and lysosomes. Rough endoplasmic reticulum, Golgi apparatus, and mitochondria were extensive in the cytoplasm. TP administration to orchidectomized rats resulted in formation of less extensive lipid droplets and mitochondria. In pinealectomized rats, golgi complex, mitochondria, and enlarged smooth endoplasmic reticulum were extensive in the cytoplasm of Leydig cells. Formation of cytoplasmic secretory granules and osmiophilic bodies was observed. Testicular weight increased compared to group IV. Melatonin decreased testicular weight in comparison to group V and prevented ultrastructural changes. Pinealectomy and orchidectomy caused hyperactivity in Leydig cells and pinealocytes, respectively, which suggests a mutual relationship between the pineal gland and testis in the rat.The ultrastructural interrelationship between the pineal gland and testis was evaluated in the rat. Wistar rats were divided into 6 groups. Groups I and II were sham-orchidectomized and orchidectomized rats, respectively. Rats in group III were orchidectomized and daily injected with testosterone propionate (TP) for 1 month. Groups IV and V were sham-pinealectomized and pinealectomized, respectively. Group VI was pinealectomized and daily injected with melatonin for 2 months. All animals were anesthetized with ketamine for fixation by vascular perfusion. Pineal glands of groups I, II, and III and the testes of groups IV, V, and VI were removed and weighed. All specimens were examined by electron microscopy. Orchidectomy caused an increase of lipid droplets, cytoplasmic dense bodies, and lysosomes. Rough endoplasmic reticulum, Golgi apparatus, and mitochondria were extensive in the cytoplasm. TP administration to orchidectomized rats resulted in formation of less extensive lipid droplets and mitochondria. In pinealectomized rats, golgi complex, mitochondria, and enlarged smooth endoplasmic reticulum were extensive in the cytoplasm of Leydig cells. Formation of cytoplasmic secretory granules and osmiophilic bodies was observed. Testicular weight increased compared to group IV.Melatonin decreased testicular weight in comparison to group V and prevented ultrastructural changes. Pinealectomy and orchidectomy caused hyperactivity in Leydig cells and pinealocytes, respectively, which suggests a mutual relationship between the pineal gland and testis in the rat.

Effects of melatonin on carbon tetrachloride-induced changes in rat serum

Carbon tetrachloride (CCl4) is a volatile organic chemical, which causes tissue damage, especially to the liver and kidney. In experimental animals it has been shown to be carcinogenic. This study was designed to evaluate the effects of exogenous melatonin administration on the CCl4-induced changes of some biochemical parameters in rat blood. Twenty-four male Wistar rats were randomly divided into three equal groups: Control, CCl4 and CCl4 plus melatonin (CCl4+MEL). Rats in CCl4 group were injected subcutaneously with CCl4 0.5 ml/kg in olive oil while rats in CCl4+MEL group were injected with CCl4 (0.5 ml/kg) plus melatonin (25 mg/kg in 10% ethanol) every other day for one month. Control rats were treated with olive oil. Serum urea, creatinine, total protein, albumin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total and conjugated bilirubin, alkaline phosphatase (ALP), gamma-glutamyl transferase (γ-GT), total iron, and magnesium levels were determined. Serum AST, ALT, total and conjugated bilirubin, ALP, γ-GT, and total iron levels were significantly higher in CCl4-treated rats than in the controls, while urea, total protein, and albumin levels were significantly lower. Melatonin treatment did not cause a significantly change in serum urea, total protein, and albumin levels. However, the elevations in AST, ALT, total and conjugated bilirubin, ALP, γ-GT, and total iron levels induced by CCl4 injections were significantly reduced by melatonin. On the other hand, melatonin administration significantly decreased serum magnesium levels. These results indicate that melatonin could be a protective agent against the CCl4 toxicity in rats, most likely through its antioxidant and free radical scavenger effects.ResumenEl tetracloruro de carbono (CCl4) es un agente cancerígeno que causa daños orgánicos, especialmente en hígado y riñón. En este trabajo se evalúan los efectos de la administración de melatonina sobre los cambios inducidos por CCl4 de algunos parámetros bioquímicos en suero de rata. Para ello, 24 ratas Wistar macho se dividieron en tres grupos (n=8): Control, CCl4 y CCl4 más melatonina (CCl4+MEL). A las ratas del grupo CCl4 se les inyectó diariamente CCl4 (0,5 ml/kg, sc en aceite de oliva) durante un mes y a las ratas CCl4+MEL se les inyectó además melatonina (25 mg/kg, sc en etanol al 10%) en días alterno. Las ratas control recibieron sólo aceite de oliva por vía subcutánea. Al final del tratamiento, se determinaron los niveles séricos de urea, creatinina, proteína total, albúmina, aspartato aminotransferasa (AST), alanina aminotransferasa (ALT), bilirrubina total y conjugada, fosfatasa alcalina (ALP), gamma-glutamil transpeptidasa (γ-GT), hierro total y magnesio. Los valores de AST, ALT, bilirrubina total y conjugada, ALP, γ-GT, y de hierro total fueron significativamente mayores en suero de ratas tratadas con CCl4 que en los controles, mientras que los niveles de urea, proteína total, albúmina fueron significativamente menores. El tratamiento de melatonina no modificó significativamente los cambios en la urea, proteína total y albúmina sérica. Sin embargo, los increamentos en los niveles de AST, ALT, bilirrubina total y conjugada, ALP, γ-GT y hierro total en suero inducidos por CCl4 se redujeron significativamente por la hormona. Además, la administración de melatonina provocó disminución de los niveles de magnesio. Los resultados indican que la melatonina puede ser un protector contra la intoxicación por CCl4 en ratas, probablemente por sus efectos antioxidantes.

Hepatotoxic activity of toluene inhalation and protective role of melatonin

This study was designed to investigate the harmful effects of toluene inhalation in the liver of rats and possible protective effects of melatonin on these detrimental effects. For this purpose, 21 adult male Wistar-albino rats were randomly divided into three equal groups. Animals in group I were used as control. The rats in group II were exposed to toluene (3000 ppm/1 hour/day) for 4 weeks, while the rats in group III were treated with melatonin (10 mg/kg/day, intraperitoneally [ip]) plus toluene inhalation. At the end of the experimental period, liver and blood samples were taken from the decapitated animals. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin and albumin levels were determined. Liver tissue sections were stained with routine histological methods and examined under the light microscope. In addition, the sections were immunohistochemically stained using avidin-biotin-peroxidase method for determination of apoptosis. The liver tissue activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and malondialdehyde (MDA) levels were also measured. Toluene inhalation significantly increased serum ALT, AST and tissue MDA, and decreased serum albumin, but did not affect serum ALP, total bilirubin levels and tissue SOD, GSH-Px and CAT activity when compared with controls. The increases in tissue MDA and serum ALT and AST levels induced by toluene inhalation were significantly inhibited by melatonin treatment. In light microscopic observations of tissues from toluene-inhaled rats, massive hepatocyte degeneration, ballooning degeneration and mild pericentral fibrosis were observed. Bax immune reactivity was also increased significantly. Melatonin treatment decreased the balloon degeneration, fibrosis and Bax immune reactivity in the liver of toluene-inhaled rats. In view of the present findings, it is suggested that melatonin has hepatoprotective effects against toluene toxicity via primarily antioxidative properties.

Effects of melatonin on Leydig cells in pinealectomized rat: an immunohistochemical study.

We have investigated immunohistochemically the effects of melatonin on Leydig cells in rat. Three groups of Wistar rats were used. Rats in group I and II were sham-pinealectomized (control) and pinealectomized, respectively, whereas rats in group III were pinealectomized and injected daily with melatonin for 2 months. At the end of the experiment, all animals were killed by decapitation and blood samples were obtained. Serum testosterone levels were determined with the use of a chemiluminescent enzyme immunoassay. Testicular tissue was collected and processed for semiquantitative evaluation of immunohistochemical testosterone staining. Intensity of immunostaining was determined on a scale between 0 (no staining) and 5 (heavy staining). In pinealectomized rats, serum testosterone levels were significantly increased as compared to sham-pinealectomized rats. Daily administration of melatonin after pinealectomy resulted in significant decreased serum testosterone levels as compared to levels in control and pinealectomized rats. Immunostaining of testosterone was moderate (3+) in sham-pinealectomized rats, heavy (5+) in pinealectomized rats and low (1+) in pinealectomized rats that were treated with melatonin, respectively. The results of our study indicate that pinealectomy induces increased testosterone secretion in Leydig cells and this increased secretion can be prevented by administration of melatonin.

Ameliorative effect of caffeic acid phenethyl ester on histopathological and biochemical changes induced by cigarette smoke in rat kidney

It was aimed to investigate the histopathological and biochemical changes in kidney tissues of rats exposed to cigarette smoke and possible protective effects of caffeic acid phenethyl ester (CAPE) on these changes. Twenty one male Wistar albino rats were divided into three equal groups. Animals in group I were used as control. Rats in group II were exposed to cigarette smoke and rats in group III were exposed to cigarette smoke and daily administration of CAPE. At the end of the 60-day experimental period, all the animals were sacrificed by decapitation. The serum samples obtained from the animals were studied for uric acid, creatinine and blood urine nitrogen (BUN) levels. Following routine histological procedures, kidney tissue specimens were examined under a light microscope. In addition, dismutase (SOD) and glutathione peroxidase (GSH-Px) enzyme activities and malondialdehyde (MDA) and nitric oxide (NO) contents were determined spectrophotometrically in tissue samples. It was found that serum uric acid and BUN levels of the rats exposed to cigarette smoke alone were elevated, although serum creatinine levels did not significantly change. Furthermore, renal SOD, GSH-Px, NO and MDA levels were significantly increased. These increases in serum BUN, and renal SOD, GSH-Px, NO and MDA levels were significantly inhibited by CAPE treatment. In light microscopic observations of tissues from rats exposed to smoke, mesangial cell proliferation in the renal corpuscles, dilatation and congestion in the peritubular capillaries and degenerative alterations in the proximal tubules were noted. There were also atrophic renal corpuscles. However, these histopathological changes were partially disappeared in the rats exposed to cigarette smoke plus CAPE. The present findings indicate that cigarette smoke causes impairment in renal structure and function, which can be prevented by CAPE administration.