The effect of bovine serum albumin-glutaraldehyde and polyethylene glycol polymer on local tissue reaction and inflammation in rabbit carotid artery anastomosis.

OBJECTIVES: In addition to the hemostatic properties of hemostatic agents, the investigation of their immunogenic properties, their local effects on application area has been the subject of many experimental studies. There are limited data on the inflammatory effects of Bovine serum albumin-glutaraldehyde and Polyethylene glycol polymer. Therefore, we investigated the effects of these agents on tissue reactions and inflammation in rabbit carotid artery anastomosis in our experimental study. METHODS: Twenty-one New Zealand male rabbits were randomly divided into three groups. The right carotid artery anastomosis was performed on the control group after transection. Hemostatic agents were applied locally to other two groups separately after transection and anastomosis. At the end of 28 days, the type of inflammation, inflammatory cell infiltration, degree of inflammation, and amount of residual adhesives were examined and compared statistically. RESULTS: Cell infiltrations associated with inflammation on the anastomosis site (eosinophils, epithelioid/giant cells, lymphocytes, and plasma cells) and inflammation grade in the groups of hemostatic agents were significantly lower compared to the control group (p < .05). There was no difference between the hemostatic agents. While mild inflammation (61.9%) was dominant in the groups of hemostatic agents, moderate inflammation (85.7%) was more common in the control group. No severe inflammation was observed in any of the three groups. Residual sealant grade between hemostatic agents did not differ significantly. CONCLUSIONS: When inflammation and tissue reactions of the 4th week were evaluated, it was determined that both hemostatic agents did not cause severe inflammation. However, comparative results at multiple time intervals are needed due to the dynamic process of inflammation.

Effects of intracerebroventricular and intravenous administration of Kisspeptin-54 and Gonadotropin-releasing hormone agonist in rats with ovarian hyperstimulation.

PURPOSE: We aim to determine the effect of local and systemic administration of kisspeptin-54 on ovarian hyperstimulation. METHODS: Immature female rats were used. In order to generate the ovarian hyperstimulation model, 50 IU PMSG was administered for 4 consecutive days and a single dose of 25 IU hCG was administered to all groups except for the sham group. To synchronize the sham group, a single dose of 10 IU PMSG followed by 10 IU hCG (48 h later) was applied. Kisspeptin-54 and gonadotropin-releasing hormone (GnRH) agonists were administered 48 h after hCG injection. While intracerebroventricular injection is performed with stereotaxic surgery, Intravenous administration was from the tail vein. Ovarian weights were measured. FSH, LH, estrogen and progesterone hormones were detected in serum by ELISA. VEGFa, IL-1ß, TNF-α, MCP-1 immunohistochemical staining was performed on the ovaries and hypothalamus and their optical densities were determined with Image J. Kiss1R mRNA expression was determined by qRT-PCR. RESULTS: Ovarian weights increased significantly in the OHSS group and the systemic GnRH agonist group. The optical densities of VEGFa, IL-1ß, TNF- α and MCP-1 immunoreactivity showed us that both local and systemic applied kisspeptin-54 attenuates the level of investigated inflammation parameters in the ovaries. Moreover, local administration of kisspeptin-54 has been shown to enhance the level of Kiss1R mRNA in both the ovaries and the hypothalamus. CONCLUSION(S): Local and systemic administration of Kisspeptin-54 as a post-treatment reduces inflammation parameters in the ovaries. These findings promote the potential use of kisspeptin-54 on OHSS.

Transcriptome Dynamics of Human Neuronal Differentiation From iPSC.

The generation and use of induced pluripotent stem cells (iPSCs) in order to obtain all differentiated adult cell morphologies without requiring embryonic stem cells is one of the most important discoveries in molecular biology. Among the uses of iPSCs is the generation of neuron cells and organoids to study the biological cues underlying neuronal and brain development, in addition to neurological diseases. These iPSC-derived neuronal differentiation models allow us to examine the gene regulatory factors involved in such processes. Among these regulatory factors are long non-coding RNAs (lncRNAs), genes that are transcribed from the genome and have key biological functions in establishing phenotypes, but are frequently not included in studies focusing on protein coding genes. Here, we provide a comprehensive analysis and overview of the coding and non-coding transcriptome during multiple stages of the iPSC-derived neuronal differentiation process using RNA-seq. We identify previously unannotated lncRNAs via genome-guided de novo transcriptome assembly, and the distinct characteristics of the transcriptome during each stage, including differentially expressed and stage specific genes. We further identify key genes of the human neuronal differentiation network, representing novel candidates likely to have critical roles in neurogenesis using coexpression network analysis. Our findings provide a valuable resource for future studies on neuronal differentiation.

The effect of bovine serum albumin-glutaraldehyde and polyethylene glycol polymer on neointimal hyperplasia in rabbit carotid artery anastomosis.

OBJECTIVE: Since the systemic drugs have been used to reduce the hyperplasic response in the tunica intima, the periadventitial local drug applications to the vascular wall have gained more popularity. In this study, we investigated the effect of bovine serum albumin-glutaraldehyde and polyethylene glycol polymer on neointimal hyperplasia in rabbit carotid artery anastomosis to explore the effects of these two different agents. METHODS: 21 New Zealand male rabbits were randomly divided into three groups. The carotid artery transection and anastomosis was performed onthe control group. The bovine serum albumin-glutaraldehyde and the polyethylene glycol polymer were applied locally on the other two groups seperatley after transection and anastomosis of the carotid arteries. At the end of 28-day follow-up, the histological and the immunohistochemical results related to neointimal hyperplasia were compared. RESULTS: The glue residues were detected in the BSA-glutaraldehyde group, but in the PEG polymer group there was no glue residue. The intima thickness and the intima/media thickness ratio in the control group was significantly higher (p<0.05) than the other groups. These values did not differ significantly between the BSA-glutaraldehyde group and the PEG polymer group (p>0.05). The lumen diameter and the area in the control group were significantly higher (p < 0.05) than the BSA-glutaraldehyde group. These values between the control group and the PEG polymer group did not differ significantly (p>0.05). aSMA-positive staining score in the Control group was found to be significantly lower (p < 0.05) than the BSA-glutaraldehyde and PEG polymer group and the VEGF-positive staining score in the control group was found to be significantly higher (p < 0.05) than the BSA-glutaraldehyde and the PEG polymer group. CONCLUSIONS: Although the both agents have positive results on neointimal hyperplasia, it would be favorable to use polyethylene glycol polymer, since it does not seem to affect the lumen area and the lumen diameter of the vessel.

Quantifying growing versus non-growing ovarian follicles in the mouse.

BACKGROUND: A standard histomorphometric approach has been used for nearly 40 years that identifies atretic (e.g., dying) follicles by counting the number of pyknotic granulosa cells (GC) in the largest follicle cross-section. This method holds that if one pyknotic granulosa nucleus is seen in the largest cross section of a primary follicle, or three pyknotic cells are found in a larger follicle, it should be categorized as atretic. Many studies have used these criteria to estimate the fraction of atretic follicles that result from genetic manipulation or environmental insult. During an analysis of follicle development in a mouse model of Fragile X premutation, we asked whether these 'historical' criteria could correctly identify follicles that were not growing (and could thus confirmed to be dying). METHODS: Reasoning that the fraction of mitotic GC reveals whether the GC population was increasing at the time of sample fixation, we compared the number of pyknotic nuclei to the number of mitotic figures in follicles within a set of age-matched ovaries. RESULTS: We found that, by itself, pyknotic nuclei quantification resulted in high numbers of false positives (improperly categorized as atretic) and false negatives (improperly categorized intact). For preantral follicles, scoring mitotic and pyknotic GC nuclei allowed rapid, accurate identification of non-growing follicles with 98% accuracy. This method most often required the evaluation of one follicle section, and at most two serial follicle sections to correctly categorize follicle status. For antral follicles, we show that a rapid evaluation of follicle shape reveals which are intact and likely to survive to ovulation. CONCLUSIONS: Combined, these improved, non-arbitrary methods will greatly improve our ability to estimate the fractions of growing/intact and non-growing/atretic follicles in mouse ovaries.

Granulosa cell and oocyte mitochondrial abnormalities in a mouse model of fragile X primary ovarian insufficiency.

STUDY HYPOTHESIS: We hypothesized that the mitochondria of granulosa cells (GC) and/or oocytes might be abnormal in a mouse model of fragile X premutation (FXPM). STUDY FINDING: Mice heterozygous and homozygous for the FXPM have increased death (atresia) of large ovarian follicles, fewer corpora lutea with a gene dosage effect manifesting in decreased litter size(s). Furthermore, granulosa cells (GC) and oocytes of FXPM mice have decreased mitochondrial content, structurally abnormal mitochondria, and reduced expression of critical mitochondrial genes. Because this mouse allele produces the mutant Fragile X mental retardation 1 (Fmr1) transcript and reduced levels of wild-type (WT) Fmr1 protein (FMRP), but does not produce a Repeat Associated Non-ATG Translation (RAN)-translation product, our data lend support to the idea that Fmr1 mRNA with large numbers of CGG-repeats is intrinsically deleterious in the ovary. WHAT IS KNOWN ALREADY: Mitochondrial dysfunction has been detected in somatic cells of human and mouse FX PM carriers and mitochondria are essential for oogenesis and ovarian follicle development, FX-associated primary ovarian insufficiency (FXPOI) is seen in women with FXPM alleles. These alleles have 55-200 CGG repeats in the 5' UTR of an X-linked gene known as FMR1. The molecular basis of the pathology seen in this disorder is unclear but is thought to involve either some deleterious consequence of overexpression of RNA with long CGG-repeat tracts or of the generation of a repeat-associated non-AUG translation (RAN translation) product that is toxic. STUDY DESIGN, SAMPLES/MATERIALS, METHODS: Analysis of ovarian function in a knock-in FXPM mouse model carrying 130 CGG repeats was performed as follows on WT, PM/+, and PM/PM genotypes. Histomorphometric assessment of follicle and corpora lutea numbers in ovaries from 8-month-old mice was executed, along with litter size analysis. Mitochondrial DNA copy number was quantified in oocytes and GC using quantitative PCR, and cumulus granulosa mitochondrial content was measured by flow cytometric analysis after staining of cells with Mitotracker dye. Transmission electron micrographs were prepared of GC within small growing follicles and mitochondrial architecture was compared. Quantitative RT-PCR analysis of key genes involved in mitochondrial structure and recycling was performed. MAIN RESULTS AND THE ROLE OF CHANCE: A defect was found in follicle survival at the large antral stage in PM/+ and PM/PM mice. Litter size was significantly decreased in PM/PM mice, and corpora lutea were significantly reduced in mice of both mutant genotypes. Mitochondrial DNA copy number was significantly decreased in GC and metaphase II eggs in mutants. Flow cytometric analysis revealed that PM/+ and PM/PM animals lack the cumulus GC that harbor the greatest mitochondrial content as found in wild-type animals. Electron microscopic evaluation of GC of small growing follicles revealed mitochondrial structural abnormalities, including disorganized and vacuolar cristae. Finally, aberrant mitochondrial gene expression was detected. Mitofusin 2 (Mfn2) and Optic atrophy 1 (Opa1), genes involved in mitochondrial fusion and structure, respectively, were significantly decreased in whole ovaries of both mutant genotypes. Mitochondrial fission factor 1 (Mff1) was significantly decreased in PM/+ and PM/PM GC and eggs compared with wild-type controls. LIMITATIONS, REASONS FOR CAUTION: Data from the mouse model used for these studies should be viewed with some caution when considering parallels to the human FXPOI condition. WIDER IMPLICATIONS OF THE FINDINGS: Our data lend support to the idea that Fmr1 mRNA with large numbers of CGG-repeats is intrinsically deleterious in the ovary. FXPM disease states, including FXPOI, may share mitochondrial dysfunction as a common underlying mechanism. LARGE SCALE DATA: Not applicable. STUDY FUNDING AND COMPETING INTERESTS: Studies were supported by NIH R21 071873 (J.J./G.H), The Albert McKern Fund for Perinatal Research (J.J.), NIH Intramural Funds (K.U.), and a TUBITAK Research Fellowship Award (B.U.). No conflict(s) of interest or competing interest(s) are noted.

The control of oocyte survival by intrinsic and extrinsic factors.

CAPSULE: Mechanisms that control the survival of oocytes and, by extension, the duration of ovarian function have been identified. However, it is still not clear whether oocyte "quality" is related to survival, nor is the role of the granulosa cells of follicles in follicle survival entirely understood. Here, we consider oocyte-intrinsic and oocyte-extrinsic mechanisms of oocyte loss and argue that developing a better understanding of such physiological events is needed to protect fertility, fecundity, and ovarian function in women.The duration that ovaries function is, as is intuitive, controlled by the number of remaining oocytes within follicles. Once the number of follicles drops beneath a threshold number, ovarian function ceases. Thus, understanding mechanisms that control oocyte survival is paramount as we consider strategies to protect or prolong ovarian function in women. It is often assumed that physiological oocyte survival is entirely controlled by "oocyte- intrinsic" factors, such as poor genetic quality or accumulated damage to the oocyte itself. Oocytes that have poor genetic quality due to development or accumulated damage would then die sooner than those of higher "quality." Indeed, new data suggest that oocyte-intrinsic genetic quality as determined by the ability to repair double-stranded DNA breaks is a significant contributor to oocyte survival and the duration of ovarian function. However, the nature of the follicle, where the oocyte and surrounding granulosa cells exist in intimate contact and rely upon each other for survival signals and metabolic function, makes it unlikely that oocyte-intrinsic factors entirely control oocyte survival. We and others are assessing the role of adjacent somatic (granulosa) cells in follicle survival, determining the relative importance of "oocyte-extrinsic" factors.

Prunus armeniaca L (apricot) protects rat testes from detrimental effects of low-dose x-rays.

Exposure to low x-ray doses damages the spermatozoa, mainly by late-onset (ie, after 3 months) oxidative stress. Antioxidants ameliorate oxidation and prevent tissue damage. Prunus armeniaca L (apricot), rich in carotenoids and vitamins, is a potent natural antioxidant. We hypothesized that an apricot-rich diet might ameliorate the detrimental effects of low-dose x-rays on testis tissue. A 20% apricot diet was composed isoenergetically to the regular rodent diet. The total phenolic content, reducing power, and antioxidant capacity of both diets were determined. Sprague-Dawley rats received apricot-rich diets before and after x-ray exposure. Regular diets were given to controls. Rats were exposed to 0.2 Gy x-rays at the eighth week and were euthanized at the 20th postexposure week. Testicular oxidative status was determined by tissue thiobarbituric acid-reactive substances, reduced glutathione, superoxide dismutase, and catalase activities. For histologic evaluation, qualitative and quantitative microscopic determinations were performed, and Leydig and Sertoli cell counts and Johnsen scores were measured. The control diet group had significant testicular oxidative stress and mild tissue deterioration. Leydig and Sertoli cell counts, tubule diameters, and Johnsen scores were significantly decreased in the exposure groups. Apricot-rich diet significantly ameliorated the oxidative status and prevented the damage in tubular histology. The protective effects were prominent when the diet was maintained throughout the time course and were partially protected when the diet was initiated after exposure. The natural antioxidant activity of apricot ameliorates the delayed detrimental effects of low-dose irradiation on testis tissue. The high total antioxidant capacity of the apricot deserves further investigation.

Effect of resveratrol on tubular damage and interstitial fibrosis in kidneys of rats exposed to cigarette smoke.

The aim of this study was to evaluate the effect of resveratrol on kidney tissue of rats exposed to cigarette smoke. Forty adult male Wistar Albino rats were divided into four groups. Animals in group 1 was the control group. For 6 weeks, group 2 was exposed to cigarette smoke; group 3 received daily intraperitoneal injections of resveratrol (10 mg/kg/d); and group 4 was exposed to both cigarette smoke and intraperitoneal resveratrol. All rats were sacrificed with cervical dislocation. The kidney tissues were obtained, fixed in Bouin's fixative and embeded in paraffin blocks. Samples were sectioned to 4-5 microns thickness, stained with hematoxylin/eosin (H/E), Masson's trichromic, periodic acid-schiff (PAS) and were examined by light microscopy for tubular injury and interstitial fibrosis. Results were compared by non-parametric tests. Hydropic degeneration, tubular atrophy, tubulo-interstitial fibrosis, interstitial cell infiltration, vacuolar degeneration and desquamation were prominent in group 2. In group 4, hydropic degeneration, epithelial cell vacuolization and desquamation was not observed, but occasional tubular atrophy and dilation were observed. Our study suggests that, some morphological alterations in the rat kidney, due to cigarette smoke may be prevented by resveratrol.

Melatonin prevents cyclosporine-induced hepatotoxicity in rats.

OBJECTIVES: Cyclosporine A (CsA) is a widely used immunosuppressive agent that is implicated in the formation of free oxygen radicals. Melatonin is known to be a free radical scavenger and an antioxidant agent. This study was designed to investigate the effects of melatonin on CsA-induced liver damage by histopathological examination. MATERIALS AND METHODS: Thirty-two male rats of Sprague-Dawley origin were divided into 4 groups of 8 and treated for 28 days as follows: group 1 received daily doses of 0.1 ml/kg olive oil s.c.; group 2 received 4 mg/kg of melatonin; group 3 received 10 mg/kg CsA diluted in 0.1 ml/kg olive oil; group 4 was treated with 4 mg/kg melatonin i.p. and 10 mg/kg CsA s.c. Finally, the rats were sacrificed by terminal anesthesia, and liver tissue specimens were processed for light microscopy, stained with HE and examined under a light microscope. RESULTS: Specimens of the control group showed normal liver histology, whereas group 3 showed major histopathological changes, such as cytoplasmic vacuolization, dilatation of the sinusoids, apoptosis and many mitotic figures. In group 4, the normal histology of the liver was preserved, although apoptosis, mitotic figures and cytoplasmic vacuolization were still infrequently observed. Nevertheless, there were significant differences between group 2 (melatonin) and group 3 (CsA) and between group 3 (CsA) and group 4 (CsA + melatonin) concerning these 3 parameters (vacuolization, sinusoidal dilatation and apoptosis). CONCLUSION: The results of this study suggest that CsA-related liver toxicity in rats could be significantly reduced by melatonin administration.

Apricot ameliorates alcohol induced testicular damage in rat model.

In this study, we intended to determine the possible preventive effects of dietary apricot on oxidative stress due to ethanol usage in rat testes. The animals were divided into six groups as follows: Group 1 was control. Group 2 received ethanol. Group 3 were fed with apricot diet for 3 months. Group 4 were fed with apricot diet for 6 months. Group 5 received ethanol and apricot diet for 3 months. Group 6 were fed apricot diet for 3 months, and then ethanol+apricot diet for 3 months. Following sacrification, the testes were treated for morphological (tubular and germ cell histology, Sertoli and Leydig cell counts) and biochemical (superoxide dismutase, glutathion peroxidase, catalase, malondialdehyde) analyses. In Group 2, severe histopathological changes in seminiferous tubules and germ cells were determined as well as tubular degeneration and atrophy. Sertoli and Leydig cell counts in the interstitial tissue were decreased. Biochemical parameters revealed tissue oxidative stress. Similar alterations existed in Group 5, although to a lesser extent. In Groups 1, 3 and 4, no histopathological alterations were noted. Results of Group 6 were similar to the controls. Apricot rich diet may have a preventive role on histopathological changes caused by alcohol in rat testes.

The effect of resveratrol in tracheal tissue of rats exposed to cigarette smoke.

OBJECTIVE: The aim of this study was to evaluate the effect of resveratrol on the tracheal tissue of rats exposed to cigarette smoke. MATERIALS AND METHODS: 40 adult Wistar albino rats were divided into four groups for an experiment of 6 weeks. Animals in group 1 were controls (n = 10). Rats in group 2 were exposed to cigarette smoke only, and rats in group 3 received daily intraperitoneal injections of resveratrol (10 mg/kg/d). Animals in group 4 were exposed to both cigarette smoke and intraperitoneal injections of resveratrol. Rats of all groups were sacrificed using cervical dislocation. The tracheas were removed and embedded in paraffin blocks. Sections of 4-5 mum thickness were prepared from the blocks. These sections were stained with hematoxylin and eosin, periodic acid-Schiff, and Alcian blue and viewed with a Leica DFC 280 light microscope. RESULTS: Tracheal sections showed that, in group 2 (cigarette smoke group), there was desquamation of epithelial cells into the tracheal lumen, loss of cilia in the epithelial layer, an increase of goblet cells, activation of serous glands at the submucosa, and cell infiltration. In group 4 (cigarette smoke + resveratrol group), all these findings also existed but only a few sections were affected. It was observed that cigarette smoking caused morphological changes such as epithelial degeneration in the upper airway. These morphological changes were correlated with the amount of toxic substances in the cigarette smoke. CONCLUSION: We found that resveratrol had a preventive role in the histopathological changes caused by cigarette smoking in the rat trachea.

Oral L-arginine protects against cyclosporine-induced hepatotoxicity in rats.

Cyclosporine A (CyA) leads to liver injury, probably by causing the production of free radicals and resulting in nitric oxide (NO) deficiency. We evaluated CyA-mediated liver damage histopathologically to determine the possible beneficial effects of L-arginine (L-Arg). In this study, 7 groups of Sprague-Dawley rats; (1) Control group; (2) 0.9% NaCl group; (3) CyA group: 7.5mg/kg/day; (4) L-Arg group: 2g/lt/day; (5) l-NAME (N-nitro-L-arginine methyl ester) group: 5mg/100ml/day; (6) CyA+L-Arg group: L-Arg (2g/lt/day)+CyA (7.5mg/kg/day); and (7) CyA+L-NAME group: CyA (7.5mg/kg/day)+L-NAME (5mg/100ml/day) were included. At the end of the treatments, animals were killed and hepatic tissues were treated for morphological (hematoxylin and eosin) and biochemical (NO and malondialdehyde, MDA) analyses, and serum was processed for biochemical (alanine transaminase (ALT), aspartate transaminase (AST), bilirubin, alkaline phosphatase (ALP) and total protein) study. The results indicated that CyA-induced hepatotoxicity was characterized by sinusoidal dilatation, hepatocellular vacuolization, neutrophilic infiltration and hepatocellular necrosis. These findings were less pronounced in the CyA+L-Arg group than CyA alone group. L-NAME group showed moderate changes. The CyA+L-NAME (Group 7) had more severe changes. We found changes in tissue NO and MDA levels. We think that the tissue damage caused by CyA is mild and reversible at the period when biochemical parameters are just starting to become abnormal and that L-Arg may have a protective effect against CyA damage on liver.

1H magnetic resonance spectroscopy of the normal testis: preliminary findings.

PURPOSE: The purpose of this study was to determine the pre- and postpubertal 1H magnetic resonance spectroscopic characteristics of the normal testis to establish baseline values for further clinical studies. MATERIALS AND METHODS: The subjects consisted of male volunteers, of whom 19 were prepubertal with ages between 7 and 13 years and 24 were postpubertal with ages between 19 and 39 years. Their testes were evaluated at 1.5 T with magnetic resonance spectroscopy; in addition, testis volumes were measured. Major metabolite peaks were identified and their ratios were calculated. Metabolite differences of testis between pre- and postpubertal age were analyzed. RESULTS: Major constituents of spectra were 3.21 ppm choline and 0.9-1.3 ppm lipid peaks. At the echo time (TE) spectrum of 31 ms, choline/lipid ratios ranged from 0.35 to 8.30 (mean=1.87) in postpubertal males and from 0.06 to 5.45 (mean=0.88) in prepubertal males (P<.013). At the TE spectrum of 136 ms, choline/lipid ratios ranged from 0.66 to 15.42 (mean=4.09) in postpubertal males and from 0.05 to 4.91 (mean=0.9) in prepubertal males (P<.016). CONCLUSIONS: Choline/lipid ratio was higher in the postpubertal period. The existence of higher choline peak in that age group should be due to the initiation of spermatogenesis. The decrease in the lipid peak may represent the effect of testosterone on testicular tissue or may be due to histochemical changes initiated by puberty. The significant decrease in choline/lipid ratio noted after puberty could represent the presence of spermatogenesis. This hypothesis should be evaluated by further studies on postpubertal subjects with impaired spermatogenesis.

Protective effect of oral L-arginine supplementation on cyclosporine induced nephropathy in rats.

BACKGROUND: One of the major adverse effects of long term cyclosporine A (CyA) administration is chronic nephrotoxicity. Several studies have suggested that alterations of the L-arginine (L-Arg) nitric oxide (NO) pathway may be involved in the pathogenesis of CyA-induced kidney damage. AIM: We postulated that in vivo activation of L-Arg-NO pathway might have a beneficial effect on CyA-induced renal damage. Conditions of chronic NO enhancement was established with L-Arg supplementation and chronic NO blockade with N-nitro-L-Arg methyl ester (L-NAME). We tested the hypothesis that, if CyA administration alters intrarenal NO synthesis, then exogenous L-Arg supplementation could limit renal injury, on the contrary, L-NAME, a potent competitive inhibitor of NO synthesis, could enhance CyA nephrotoxicity. Harmful effect of NO blockade indirectly supports the beneficial effect of NO in a model of CyA nephrotoxicity. METHODS: Rats were administered vehicle (VH), CyA (7.5 mg/kg/day), CyA + L-Arg (2g/kg/day), CyA + L-NAME (5 mg/100 ml/day), CyA + L-Arg + L-NAME, VH + L-Arg, VH + L-NAME and were sacrificed at the end of the experiment. Body weight, serum creatinine, blood urea nitrogen (BUN) and NO levels were determined. Tubular injury and interstitial fibrosis were evaluated semiquantitatively using scoring systems on paraffin sections stained with hematoxylin/eosin (H/E), Masson's trichromic and periodic acid-Schiff (PAS). RESULTS: The CyA group developed marked renal injury, characterized by a significant increase in serum creatinine and BUN, and histopathological alterations including tubular dilatation, vacuolization, necrosis, interstitial cell infiltration and tubulointerstitial fibrosis. CyA reduced serum NO level. L-Arg treatment significantly enhanced NO biosynthesis and protected animals from CyA-induced kidney damage. In contrast L-NAME strikingly reduced serum NO level, and worsened biochemical and histopathological alterations. CONCLUSION: Chronic CyA nephrotoxicity can be aggravated by NO blockade and ameliorated by NO enhancement suggesting that L-Arg supplementation may be protective in CyA nephrotoxicity.

Ultrastructural clues for glutamate-induced necrosis in parietal and cerebellar neurons.

Glutamate excitotoxicity has been postulated to underlie the neuronal death that occurs after ischemia. The most sensitive tissues to ischemic injury are hippocampus and cerebellum, whereas cerebrum is more resistant. We studied the glutamate-induced ultrastructural alterations in rat parietal and cerebellar neurons comparatively. We observed that glutamate (45 min, 10-7 m) causes considerable nuclear, mitochondrial and cytoplasmic changes in both the neuron types. Mitochondrial and nuclear changes were particularly more severe in cerebellar granular, than the ones in parietal neurons. It has been concluded that glutamate induces necrotic changes in both parietal and cerebellar neurons. But cerebellar cortex was found to be more sensitive to glutamate excitotoxicity than cerebral cortex. We suggest that mitochondrial damage is, probably, an important factor in neuron necrosis, which is mediated by glutamate excitotoxicity.