The protective effects of caffeic acid phenethyl ester against toluene-induced nephrotoxicity in rats.

Caffeic acid phenethyl ester (CAPE) has antioxidant and anti-inflammatory properties. The aim of this study is to examine the negative effects of toluene on kidney tissues and functions and to investigate the protective effects of CAPE against toluene-induced nephrotoxicity in rats. A total of 21 male Wistar rats were divided into three groups of equal number in each. The rats in group I were the controls. Toluene was intraperitoneally injected into the rats in group II with a dose of 500 mg/kg. Rats in group III received CAPE daily while exposed to toluene. After 14 days of experimental period, all rats were killed by decapitation. Enzymatic activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) and malondialdehyde (MDA) levels were studied in the rat kidneys. Blood urea nitrogen (BUN) and serum creatinine levels were measured for renal function. The CAT and SOD enzyme activities and serum creatinine levels were significantly increased in rats treated with toluene when compared with the controls. But GSH-Px activity, MDA, and BUN levels showed statistically nonsignificant changes. However, increased CAT and SOD enzyme activities and decreased serum creatinine levels were detected in the rats that received CAPE while exposed to toluene. The GSH-Px activity and MDA and BUN levels in the same group did not show statistically significant changes. The results of our study demonstrated that toluene damages kidney tissue and is a nephrotoxic substance. CAPE was able to prevent the renal damage as antioxidant, antitoxic, and nephroprotective agent.

Atlas-based structural analysis of prefrontal cortex atrophy in major depressive disorder: Correlations with severity and episode frequency.

BACKGROUND: Current models of major depressive disorder (MDD) primarily focus on the structural and functional changes in key prefrontal areas responsible for emotional regulation. Among these regions some sections such as the dorsal prefrontal area, has received limited attention regarding its structural abnormalities in MDD. This study aims to evaluate volumetric abnormalities in brain regions associated with markers of depression severity and episode frequency. METHODS: The study included 33 MDD patients and 33 healthy subjects. Using an atlas-based method, we measured the volumes of several key brain regions based on MRI data. The regions of interest included prefrontal and posterior sections of the middle frontal gyrus (MFG) and superior frontal gyrus (SFG). Additionally, we evaluated the volumes of the dorsal anterior cingulate cortex (dACC), perigenual (rostral) anterior cingulate cortex (pgACC), subgenual cingulate cortex (sgACC), posterior cingulate cortex (PCC), hippocampus (HPC), and parahippocampus (paraHPC). Hamilton Depression Scale (HAM-D) scores and count of the depressive episodes of patients were also obtained. A regression analysis with sex as the confounding factor has been made. RESULTS: Analysis of covariances, controlling for sex, showed significant atrophy in the sgACC in the depression group: F(1, 63) = 4.013, p = 0.049 (left) and F(1, 63) = 8.786, p < 0.004 (right). Poisson regression, also controlling for sex, found that each additional depressive episode was associated with a significant reduction in left posterior MFG volume (0.952 times, 95 % CI, 0.906 to 1.000; p = 0.049). CONCLUSIONS: Findings in this study highlight the structural abnormalities in MDD patients in correlation to either current depression severity or chronicity of the disease.

Effects of melatonin hormone on hippocampus in pinealectomized rats: an immunohistochemical and biochemical study.

OBJECTIVE: The effects of melatonin on antioxidant status were examined in pinealectomized rats using enzymatic, histological and immunohistochemical techniques. The aim of this study is to investigate the effects of melatonin on hippocampal apoptosis. MATERIALS AND METHODS: Male Wistar rats (n=21) were divided into 3 groups: Group I and group II were designated as control (sham-pinealectomy) and pinealectomized rats, respectively. Rats in group III were pinealectomized and injected daily with melatonin (1 mg/kg) for 3 months beginning at day 7 after surgery. At the end of experimental period, all rats were killed by decapitation. The brains of the rats were removed and the hippocampus tissue was obtained from all brain specimens. The right hippocampal specimens of all rats were used for determination of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) levels. The left hippocampus tissue specimens of all animals were used for immunohistochemical and histological evaluation. RESULTS: The levels of SOD and GSH-Px were significantly decreased, and MDA levels were significantly increased in pinealectomized rats compared to the controls. In the histological and immunohistochemical evaluation of this group, increase of pyknotic cells, vacuolar degeneration and apoptosis were observed. However, increased SOD and GSH-Px enzyme activities, and decreased MDA levels were detected in the rats administered melatonin after pinealectomy. Furthermore, histological and apoptotic changes in hippocampus caused by pinealectomy were lost in the rats treated with melatonin. CONCLUSIONS: The results of our study revealed that pinealectomy-induced oxidative damage and morphological changes in the hippocampal tissue were suppressed by melatonin.

Effect of endostatin on 1,2-dimethylhydrazine-induced colon tumor in mice.

Endostatin, one of the most potent negative regulators of angiogenesis, is naturally occurring as an inhibitor of angiogenesis capable of inhibiting tumor growth and their metastases. We aimed to investigate the in vivo activities of low dose of recombinant human endostatin on 1,2-dimethylhydrazine (DMH)-induced mice colon cancer. Thirty male Balb-c mice were injected with DMH (20 mg/kg/week) subcutaneously once a week for 12 weeks to induce colon cancer. Twelve weeks after the last DMH injection, 7 µg rh-endostatin was injected every day for 6 weeks. The animals were killed after 30 weeks for histopathological examination. The weight of the animals, tumor inhibition rates, death rates and the distribution of the lesions in colon were evaluated after the mice were killed. The mean colonic lesions incidence in single tumor bearing mice was 11 ± 4.0 in those treated with DMH and 8.1 ± 3.7 in those treated with endostatin. When we look at the distribution of lesions in the colon, they occurred in the distal colon. At the end of our study, we noticed that the number of lesions decreased by 25% in the group of endostatin, considering the number of the lesions in the group of DMH. But there was no statistical difference between the mice treated with endostatin and those treated with DMH. It will be very significant to identify endostatin therapeutic effects as long as proper dose of endostatin is administrated at the proper time, duration and proper tumor model.

Protective effects of CAPE on liver injury induced by CCL4: an electron microscopy study.

This study was designed to investigate the protective effects of caffeic acid phenethyl ester on carbon tetrachloride-induced liver damage in rats. Twenty-four male Wistar rats were divided in three groups. Group I was used as control. Rats in group II were injected with carbon tetrachloride every other day for 1 month, whereas rats in group III were injected with carbon tetrachloride and caffeic acid phenethyl ester every other day for 1 month. At the end of the experiment, all animals were killed by decapitation and their livers were removed. Liver tissues were processed for electron microscopy. Histopathologically, hepatocytes of rats treated with carbon tetrachloride had damage in the cytoplasmic organelles and nuclei membranes as well as an excessive lipid accumulation in the hepatocytes. However, those histopathological changes were reduced with the coadministration of carbon tetrachloride and caffeic acid phenethyl ester. We conclude that caffeic acid phenethyl ester treatment has the capability to prevent carbon tetrachloride-induced liver damage in rats.

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.

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.

Volume estimation of brain ventricles using Cavalieri's principle and Atlas-based methods in Alzheimer disease: Consistency between methods.

Automatic estimations of brain ventricles are needed to assess disease progression in neurodegenerative disorders such as Alzheimer Disease (AD). The objectives of this study are to evaluate the diagnostic performances of an automated volumetric assessment tool in estimating lateral ventricle volumes in AD and to compare this with Cavalieri's principle, which is accepted as the gold standard method. This is across-sectional volumetric study including 25 Alzheimer patients and 25 healthy subjects undergoing magnetic resonance images (MRI) with a 3D turbo spin echo sequence at 1.5 Tesla. The Atlas-based method incorporated MRIStudio software to automatically measure he volumes of brain ventricles. To compare the corresponding measurements, we used manual point-counting and semi-automatic planimetry methods based on Cavalieri's principle. Bland-Altman test results indicated an excellent agreement between Cavalieri's principle and the Atlas-based method in all volumetric measurements (p < 0.05). We obtained a 64% sensitivity and 92% specificity for lateral ventricular volumes according to the Atlas-based method. AD subjects had significantly larger left and right lateral ventricle volume (LVV) when compared to control subjects in respect to three volumetric methods (p < 0.01). Lateral ventricle-to-brain ratio (VBR) statistically increased 49.23% in measurements done with the point-counting method, 45.12% with the planimetry method, and 45.49% with the Atlas-based method in AD patients (p < 0.01). As a result, the Atlas-based method may be used instead of manual volumetry to estimate brain volumes. Additionally, this method provides rapid and accurate estimations of brain ventricular volumes in-vivo examination of MRI.

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.

Protective effect of omega-3 fatty acids in a rat focal cerebral ischemia-reperfusion model.

OBJECTIVE: To investigate possible neuroprotective effects of dietary supplementation of fish oil in brain ischemia-reperfusion (I/R). METHODS: This investigation took place in the Experimental Research Unit, Firat University, Elazig, Turkey, from January-February 2006. The study was carried out on 12 male Wistar rats; divided into 2 groups: I/R (control) and I/R + omega-3 essential fatty acids (EFA) (experiment). The rats in the I/R group received only ordinary rat food before middle cerebral artery (MCA) occlusion. The I/R + omega-3 EFA group received omega-3 fatty acid daily via intragastric gavage (300 mg/kg Marincap capsule) with normal food before MCA occlusion for 30 days. Structural alterations in the brain tissues were semi-quantitatively analyzed (0: absent, +: slight, ++: moderate, +++: severe). RESULTS: There was evident severe (+++) edema, vacuolization, and eosinophilic degeneration in the I/R group, while only slight (+) edema and eosinophilic degeneration in the I/R + omega-3 EFA group in which no vacuolization was determined. These findings are consistent with the available studies in this field. CONCLUSION: Results from this study indicate the beneficial effects of omega-3 EFA supplementation in prevention of I/R - induced damage in rats.

Oxidative stress in testicular tissues of rats exposed to cigarette smoke and protective effects of caffeic acid phenethyl ester.

AIM: To show the oxidative stress after cigarette smoke exposure in rat testis and to evaluate the effects of caffeic acid phenethyl ester (CAPE). METHODS: Twenty-one rats were divided into three groups of seven. Animals in Group I were used as control. Rats in Group II were exposed to cigarette smoke only (4 x 30 min/d) and rats in Group III were exposed to cigarette smoke and received daily intraperitoneal injections of CAPE (10 micromol/kg x d). After 60 days all the rats were killed and the levels of nitric oxide (NO) and anti-oxidant enzymes such as superoxide-dismutase, catalase and glutathione peroxidase (GSH-Px) and the level of malondialdehyde were studied in the testicular tissues of rats with spectrophotometric analysis. RESULTS: There was a significant increase in catalase and superoxide-dismutase activities in Group II when compared to the controls, but the levels of both decreased after CAPE administration in Group III. GSH-Px activity was decreased in Group II but CAPE caused an elevation in GSH-Px activity in Group III. The difference between the levels of GSH-Px in Group I and Group II was significant, but the difference between groups II and III was not significant. Elevation of malondialdehyde after smoke exposure was significant and CAPE caused a decrease to a level which was not statistically different to the control group. A significantly increased level of NO after exposure to smoke was reversed by CAPE administration and the difference between NO levels in groups I and III was statistically insignificant. CONCLUSION: Exposure to cigarette smoke causes changes in the oxidative enzyme levels in rat testis, but CAPE can reverse these harmful effects.

Potential role of dietary omega-3 essential fatty acids on some oxidant/antioxidant parameters in rats' corpus striatum.

Omega-3 (omega-3) is an essential fatty acid (EFA) found in large amounts in fish oil. It contains eicosapentaenoic acid and docosahexaenoic acid (DHA). DHA is one of the building structures of membrane phospholipids of brain and necessary for continuity of neuronal functions. Evidences support the hypothesis that schizophrenia may be the result of increased reactive oxygen species mediated neuronal injury. Recent reports also suggest the protective effect of omega-3 EFA against neuropsychiatric disorders including schizophrenia. This study proposed to assess the changes in antioxidant enzyme and oxidant parameters in the corpus striatum (CS) of rats fed with omega-3 EFA diet (0.4g/kg/day) for 30 days. Eight control rats and nine rats fed with omega-3 were decapitated under ether anesthesia, and CS was removed immediately. Thiobarbituric acid-reactive substances (TBARS) and nitric oxide (NO) levels as well as total superoxide dismutase (t-SOD) and xanthine oxidase (XO) enzyme activities in the CS were measured. Rats treated with omega-3 EFA had significantly lower values of TBARS (P<0.001), NO (P<0.002) and XO (P<0.005) whereas higher values of t-SOD enzyme activity (P<0.002) than the control rats. These results indicate that omega-3 EFA rich fish oil diet reduces some oxidant parameters in CS. This may be revealed by means of reduced CS TBARS levels as an end product of lipid peroxidation of membranes in treated rats. Additionally, reduced XO activity and NO levels may support this notion. On the other hand, although the mechanism is not clear, omega-3 EFA may indirectly enhance the activity of antioxidant enzyme t-SOD. Taken together, this preliminary animal study provides strong support for a therapeutic effect of omega-3 EFA supplemented to classical neuroleptic regimen in the treatment of schizophrenic symptoms and tardive dyskinesia.

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.

Zinc, copper and iron concentrations in cerebral cortex of male rats exposed to formaldehyde inhalation.

Retrospective cohort studies and clinical findings have suggested effects of formaldehyde exposure on the central nervous system in anatomists, embalmers and pathologists. On the other hand, harmful effects of formaldehyde inhalation on the nervous system are not well documented. The concentrations of elements such as zinc, copper and iron within the cerebral cortex indicate whether physiological conditions are maintained. In this study, adult male albino Wistar rats were exposed to formaldehyde at different concentrations (0; 6.1; 12.2 mg x m(-3)) and during different periods of time (subacute-subchronic), and body weights were recorded weekly. Zinc, copper and iron concentrations were measured in the parietal cortex using atomic absorption spectrometry after wet ashing. We conclude that subacute or subchronic exposure to formaldehyde may cause growth retardation and alter zinc, copper and iron levels in the cerebral cortex.

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.

Protective effects of caffeic acid phenethyl ester (CAPE) on carbon tetrachloride-induced hepatotoxicity in rats.

In the present study, protective effects of caffeic acid phenethyl ester (CAPE) have been evaluated on carbon tetrachloride (CCl4)-induced hepatotoxicity in rat. Twenty-four male Wistar rats were divided in three groups. Group I was used as control. Rats in group II were injected every other day with CCl4 for 1 month, whereas rats in group III were injected every other day with CCl4 and CAPE for 1 month. At the end of the experiment, all animals were killed by decapitation and blood samples were obtained. Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total and conjugated bilirubin levels and hepatic malondialdehyde (MDA) contents were determined. For histopathological evaluation, livers of all rats were removed and processed for light microscopy. All biochemical parameters in serum and the hepatic MDA content were significantly higher in animals treated with CCl4 than in the controls. Rats treated with CCl4 and CAPE showed a significant reduction in biochemical parameters in serum and hepatic MDA content. Livers of rats treated with CCl4 showed classic histology of cirrhosis, whereas the histopathological changes were reduced after administration of CCl4 and CAPE. A normal lobular appearance was observed in livers in this group except for fatty degeneration. The results of our study indicate that CAPE treatment prevents CCl4-induced liver damage in rats.

Effects of estradiol benzoate on the ultrastructure of the pinealocyte in the ovariectomized rat.

OBJECTIVE: The aim of this study was to examine the effects of ovariectomy and ovariectomy followed by estradiol benzoate administration on the ultrastructure of pinealocytes in female rat. DESIGN: For this purpose 15 female Wistar rats were used. Animals were divided into three groups. Group I and II were designated as sham-ovariectomized (control) and ovariectomized, respectively. Group III was ovariectomized and daily injected with estradiol benzoate for one month. At the end of the experiment, all animals were anesthetized with ketamine for fixation by vascular perfusion. Pineal glands of groups I, II and III were removed. All specimens were examined by electron microscopy. RESULTS: Ovariectomy caused an increase of lipid droplets, mitochondria and ribosomes. Rough endoplasmic reticulum was extensive in the cytoplasm. Estradiol administration to ovariectomized rats resulted in formation of less extensive lipid droplets, mitochondria and ribosomes compared to pinealocyte ultrastructure of both control and ovariectomized rats. Extensiveness of rough endoplasmic reticulum in the pinealocytes of estradiol-administrated rats was similar to that in controls. CONCLUSIONS: The results confirm relationship between the pineal gland and gonads in the rat and it has been suggested that estradiol benzoate reverses the ultrastructural changes, which indicate increased cell activation, occurring in the pinealocytes after ovariectomy.

The effects of photoperiod on testes in rat: a morphometric and immunohistochemical study.

OBJECTIVE: The aim of this study was to examine the effects of photoperiod on testes in rat. DESIGN: For this purpose 21 male Wistar rats were used. Animals were divided into three groups. Control rats in group I were kept under 12 hrs light: 12 hrs dark conditions (12L: 12D) for 10 weeks. Animals in group II were exposed to long photoperiods (18L: 6D), while rats in group III were exposed to short photoperiods (6L: 18D) for 10 weeks. 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. The testes of all rats were removed and weighed. Testicular tissue was processed semiquantitative evaluation of immunohistochemical testosterone staining. Intensity of immunostaining was determined on a scale between 0 (no staining) and 5 (heavy staining). For morphometric comparison, diameters of seminiferous tubules in each group were measured. RESULTS: In rats exposed to long photoperiods, testicular weights, diameters of seminiferous tubules and serum testosterone levels were significantly increased as compared to those in control rats. Whereas, exposure of rats to short photoperiods resulted in significantly decrease of testicular weights, diameters of seminiferous tubules and serum testosterone levels as compared to those in control rats and rats maintained in long photoperiods. Immunostaining of testosterone was moderate (3+) in control rats, heavy (5+) in rats exposed to long photoperiods and minimal (1+) in rats exposed to short photoperiods. CONCLUSIONS: The results of our study indicate that testicular functions increase after exposure to long photoperiods and decrease after exposure to short photoperiods.

Light and electron microscopic examination of pineal gland in rats exposed to constant light and constant darkness.

OBJECTIVE: This study was aimed to examine the pineal gland of rats exposed to constant light and darkness at light and electron microscopic level. DESIGN: For this purpose 18 male Wistar rats were used. Animals were divided into three groups. Rats in group I (Control) were kept under 12 hrs light: 12 hrs dark conditions. Rats in group II were exposed to constant darkness, while rats in group III were exposed to constant light for 6 weeks. At the end of the experiment, all animals were killed by decapitation. The pineal glands of rats were removed, then processed for light and electron microscopy. RESULTS: In our study, extensive number of pinealocytes was observed in the structure of pineal gland of rats exposed to constant darkness and some of the observed pinealocytes were determined to contain double nucleoli. Furthermore, mitochondria and lipid droplets in the cytoplasm of pinealocytes were increased and rough endoplasmic reticulum sacs were enlarged in this group. Whereas, in rats those exposed to the constant light, a decrease in pinealocyte intensity was associated with increase in the connective tissue between parenchymal cells. Additionally, mitochondria and lipid droplets in the cytoplasm of cells were decreased. CONCLUSIONS: It was observed that the pinealocyte cell activity of rats exposed to constant darkness was increased but decreased in rats exposed to constant light.