Característica histológica, ultra-estrutural e produção de nitrito de folículos pré-antrais caprinos cultivados in vitro na ausência ou presença de soro / Histological and ultrastructural feature and nitrite production of caprine preantral follicles in vitro cultured in the presence or absence of serum

Avaliou-se o efeito da adição de diferentes tipos e concentrações de soro sobre o desenvolvimento e a sobrevivência de folículos ovarianos pré-antrais (FOPA) caprinos in vitro. Além disso, verificou-se a relação entre as concentrações de nitrito presentes no meio de cultivo e a viabilidade folicular. Cada par ovariano foi dividido em 29 fragmentos, sendo um destinado ao controle. Os fragmentos foram cultivados por um ou sete dias em meio essencial mínimo suplementado (MEM+) ou MEM+ com diferentes concentrações (10 ou 20 por cento) de soro fetal bovino (SFB), soro de cabra em estro (SCE) ou soro de cabra em diestro (SCD). Na análise morfológica após sete dias, apenas o tratamento com 10 por cento de SFB apresentou percentual de FOPA normais similar ao MEM+ (P>0,05). A análise ultra-estrutural dos folículos cultivados por sete dias com MEM+ ou MEM+ com 10 por cento de SFB mostrou danos oocitários, porém células da granulosa normais. A análise do meio de cultivo revelou correlação positiva entre a viabilidade folicular e a produção de nitrito. A suplementação com soro não melhorou a viabilidade de FOPA e a concentração de nitrito no meio de cultivo funcionou como um indicador da viabilidade das células da granulosa de FOPA caprinos cultivados in vitro.

The effect of the addition of different types and concentrations of sera on the viability and development of caprine preantal follicles (PAF) in vitro cultured was analyzed. In addition, it was evaluated the correlation between nitrite concentrations in culture medium and folicular viability. Each ovarian pair was divided in 29 fragments and one was used as control. The fragments were cultured for one or seven days in minimal essential medium (MEM+) or MEM+ with different concentrations of (10 or 20 percent) bovine fetal serum (BFS), estrous goat serum (EGS), or diestrous goat serum (DGS). After seven days, the morphological analysis showed that only the treatment with 10 percent BFS maintained the percentage of normal PAF similar to MEM+ (P>0.05). The ultrastructural analysis of follicles cultured for seven days in MEM+ or MEM+ with 10 percent BFS showed some oocyte damage, although the granulosa cells were normal. Analysis of culture medium revealed a positive correlation between follicular viability and nitrite production. Supplementation with serum did not improve the viability of PAF and nitrite levels in culture medium served as an indicator of viability of granulose cells from caprine PAF in vitro cultured.

Effects of the vitamin E in catalase activities in hippocampus after status epilepticus induced by pilocarpine in Wistar rats.

Experimental manipulations suggest that in vivo administration of exogenous antioxidants agents decreases the concentration of free radical in the brain. Neurochemical studies have proposed a role for catalase in brain mechanisms responsible by development to status epilepticus (SE) induced by pilocarpine. The present study was aimed at was investigating the changes in catalase activities after pilocarpine-induced SE. Animals were treated with vitamin E (VIT E) 200 mg/kg (intraperitoneally (i.p.)) and, 30 min later, they received pilocarpine hydrochloride, 400 mg/kg, subcutaneous (s.c.) (P400). Other three groups received VIT E (200 mg/kg, i.p.), pilocarpine (400 mg/kg, s.c.) or 0.9% NaCl (control) alone. Animals were closely observed for behavioral changes, tremors, stereotyped movements, seizures, SE and death, for 24 h following the pilocarpine injection. The brains were dissected after decapitation. The results have shown that pilocarpine administration and resulting SE produced a significant increase in hippocampal catalase activity of (88%). In the group pre-treated which VIT E in hippocampal catalase activity was increase of 67% and 214% when compared with P400 and control group, respectively. Our results demonstrated a direct evidence of an increase in the activity of the hippocampal catalase of rat adults during seizure activity and after the pre-treated which VIT E that could be responsible by regulation of free radical levels during the establishment of SE.

Quebrachitol (2-O-methyl-L-inositol) attenuates 6-hydroxydopamine-induced cytotoxicity in rat fetal mesencephalic cell cultures.

Naturally occurring plant substances have the potential to prevent oxidative damage in various pathophysiological conditions including neurodegenerative disorders. Recent findings indicate that impaired energy metabolism plays a prominent role in neurodegeneration. The present study investigated whether quebrachitol (2-O-methyl-L-inositol) (QCT), a sugar like natural compound that was suggested to have both antioxidant and membrane stabilization activity prevents the cytotoxic effect of 6-hydroxydopamine (6-OHDA, 200 microM) on cultured rat fetal mesencephalic cells. While QCT (0.1-100 microg/ml) produced no effect per se on cell viability as measured in the 3[4,5-dimethylthiazole-2il]-2,5-diphenyltetrazolium bromide (MTT) test, it offered concentration-related protection against cell death induced by 6-OHDA. In addition, QCT demonstrated an antioxidant activity against 6-OHDA-induced oxidative stress as evidenced by reduced formation of nitrite-nitrate and thiobarbituric acid-related substances. Fluorescence microscopy using acridine orange/ethidium bromide double staining further affirmed the absence of 6-OHDA (200 microM)-induced morphological changes characteristic of apoptosis/necrosis in cultures pretreated with QCT (100 microg/ml). Also, results of tyrosine hydroxylase immunoreactivity indicated that 6-OHDA induces cell death in mesencephalic cultures affecting both TH+ positive and TH- negative (TH+ and TH-, respectively) and QCT pretreatment protects them from cell death, in a non-specific manner. Our data indicate that QCT has a cytoprotective role due, at least in part, to an antioxidant and free radical scavenging mechanism. Furthermore, the study suggests that inositol compounds might serve as leads in developing drugs for the treatment of various neurodegenerative disorders.

l-Deprenyl prevents lipid peroxidation and memory deficits produced by cerebral ischemia in rats.

1. The present work shows the results on behavior and on biochemical parameters of l-deprenyl (0.1, 5, and 10 mg/kg, p.o.) administered daily for 5 days to rats submitted to global cerebral ischemia. 2. The transient global ischemia was carried out by clamping the animals bilateral common carotid arteries for 20 min. The parameters studied were memory acquisition and memory retention, locomotor activity and thiobarbituric acid reactive substances, as an index of lipid peroxidation. 3. l-Deprenyl treatment significantly improved memory deficits as compared to the ischemic group as measured by the elevated T maze test. A similar result was observed on the passive avoidance test where l-deprenyl improved late but not early memory as compared to the ischemic group. Except for an increased locomotor activity observed in the group treated with 5 mg/kg, no other alteration was detected in this behavioral test. Rats submitted to transient global ischemia (and without l-deprenyl) showed an increase in MDA levels in the hippocampus and the treatment with l-deprenyl (5 or 10 mg/kg) significantly reversed this effect bringing values close to those of the sham-operated controls. A similar profile was observed with nitrite levels. 4. In conclusion, the work showed a significant protective effect of l-deprenyl on memory deficits and lipid hyperperoxidation observed after cerebral ischemia. Possibly, the drug is acting at least in part through its antioxidant activity.

Catechin attenuates 6-hydroxydopamine (6-OHDA)-induced cell death in primary cultures of mesencephalic cells.

Past studies have shown the protective effects of tea catechins on oxidative cell damage induced by 6-OHDA in PC12 cells. In this study we verified whether or not catechin prevents 6-OHDA-induced oxidative cell damage in primary cultures of rat mesencephalic cells. On exposure to 6-OHDA (200 microM), the cultures showed a marked decrease in cell viability, disturbances in lipid peroxidation, and an increased generation of NO, as assayed by MTT, TBARS and nitrite assays, respectively. Introduction of catechin significantly attenuated the cell death caused by 6-OHDA at concentrations of 3.4, 34 and 340 microM in a dose-related manner. Catechin produced no marked changes on 6-OHDA-induced increases in NO, but caused a significant inhibition of lipid peroxidation. These results suggest that catechins offer similar cytoprotection against 6-OHDA-induced oxidative cell damage in mesencephalic cell cultures, as previously described in PC12 cells. The cytoprotective function of catechin results from its antioxidant property and is not due to the inhibition of nitric oxide synthase. These findings further support and substantiate traditional consumption of catechin rich green/black tea as protection against neurodegenerative diseases like Parkinsonism.