Antioxidant profile changes in reproductive tissues of rats treated with nicotine.

OBJECTIVES: Nicotine intake has been associated with reduced fertility, although the mechanisms responsible are still unclear. However, oxidative stress has been repeatedly implicated as the leading cause of male infertility. This study was therefore designed to investigate the effects of nicotine administration on testicular oxidant and antioxidant system in male albino rats. MATERIALS AND METHODS: Forty male rats weighing between 150 and 180 g were divided into five groups and treated orally for 30 days. Group I, which served as the control received 0.2 ml/kg normal saline, Groups II and III received 0.5 mg/kg and 1.0 mg/kg body weight (BW) of nicotine respectively. The fourth and fifth groups were administered with 0.5 mg/kg and 1.0 mg/kg BW of nicotine, but were left untreated for another 30 days. Homogenate of testis and epididymis were assayed for lipid peroxidation and anti-oxidant enzyme. RESULTS: The results show a significant decrease (P < 0.05) in testicular glutathione peroxidase, glutathione reductase, catalase and superoxide dismutase while a significant increase (P < 0.05) was observed in testicular lipid peroxidation and nitric oxide level in both groups when compared with the control. CONCLUSION: This experiment established that nicotine administration is associated with decreased testicular antioxidant and increase testicular lipid peroxidation, which might be a mechanism by which nicotine induce infertility.

Gastro-protective effect of methanol extract of Ficus asperifolia bark on indomethacin-induced gastric ulcer in rats.

The gastro-protective and antioxidant effects of methanol extract of Ficus asperifolia bark on indomethacin induced gastric ulcer were investigated in male rats. Thirty two male rats divided into 4 equal groups and were treated as follows: group1 (control), 0.5ml of 5% tween 80 (vehicle for the extract), groups 2 and 3, 100 and 500mg/kg of Ficus asperifolia extract respectively and group 4, cimetidine (100mg/kg). After two weeks of daily oral administration of vehicle, extract or cimetidine, gastric ulcer was induced in all rats with indomethacin (40 mg/kg, p.o). Gastric juice pH, gastric acid concentration, gastric ulcer score, percentage gastric ulcer inhibition, activity levels of superoxide dismutase (SOD), catalase and malondiadehyde (MDA) were determined. Ficus asperifolia extract significantly increased gastric pH (p<0.05) but decreased (p<0.01) gastric acid secretion in dose dependent manner when compared with the control. Inhibition of gastric ulcer in extract and cimetidine treated rats was similar. Activities of SOD and catalase were significantly increased (p<0.05) while MDA was significantly decreased (p< 0.05) in extract treated rats when compared with the control. The results suggest that Ficus asperifolia possesses gastro-protective and antioxidant properties against gastric ulcer induced by indomethacin.

Effects of oral administration of nicotine on organ weight, serum testosterone level and testicular histology in adult male rats.

This study investigated the effects of oral administration of nicotine on body and reproductive organ weight, serum testosterone level and testicular histology in adult male rats. Forty male rats divided into five groups and treated for a period of 30 days with 0.5mg/kg (low dose) and 1.0 mg/kg (high dose) body weight of nicotine while the control rats received 0.2 ml/kg normal saline. The fourth and fifth groups were gavaged with 0.5mg/kg and 1.0mg/kg body weight of nicotine but were left untreated for another 30 days. These groups served as the recovery groups.  At the end of each experimental period, the animals were scarified and their reproductive organs were removed and weighed immediately. There was no significant change in the body weight. There was a significant decrease (p <0.05) in the testicular and epididymal weight of rats for both treatments while the decrease in the seminal vesicle weight for both treatment groups was not significant. The prostate weight was not significantly increased in both groups. The recovery groups showed appreciable recovery in their organ weight. Serum level of testosterone of both groups was significantly decreased in a dose dependent manner when compared with those of the control rats. The histological section showed testicular degeneration and disorganization in the cytoarchitecture, as the observed changes were pronounced in the high dose group than the low dose group. However, there were both regeneration of the germinal epithelium and restructuring of the interstitum towards normal in the recovery groups. No lesion was observed in the epididymis of the rats. The results suggest that nicotine has deleterious effect on the male reproductive organ of albino rats ameliorated by nicotine cessation.

Effect of nicotine administration on weight and histology of some vital visceral organs in female albino rats.

It has been emphasized that cigarette smoking is not always synonymous with nicotine administration but the toxic effect of cigarette has often been associated with the nicotine content in cigarette. Epidemiologic studies have clearly indicated that cigarette smoking have many deleterious effects on visceral tissues in women. However it is not certain whether this effect is produced entirely by nicotine as cigarettes contain other toxic substances. Using an animal model, the direct effect of nicotine administration on viscera tissues in female albino rats was investigated. Twenty-four female rats with regular oestrous cycle in the same phase of the cycle were divided into two equal groups with each group receiving 0.5 mg/kg nicotine and 0.9% normal saline S.C. daily respectively. Six rats from each group were killed by cervical dissociation after 30 and 60 days treatment. The ovary, uterus, brain, kidney, heart, adrenal, pituitary and the liver were removed, weighed and histological study carried out. Weights of the ovary, kidney, pituitary and uterus were significantly [P<0.05] reduced following nicotine treatment while weights of the heart and liver increased with 60 days treatment with the appearance of cartilaginous cells in the heart and deposition of adipose around the portal vein in the liver. Necrosis, congestion, fibrosis, follicular and endometrial degeneration were observed in the brain, pituitary, kidney, ovary and uterus respectively. No significant difference was noted between the weekly growth rates in nicotine treated [5.13+/-0.29] and control [5.25+/-0.18] animals. Nicotine has deleterious effects on some vital visceral organs with observations similar to those reported in women smokers.

Implication of reproductive endocrine malfunction in male antifertility efficacy of Azadirachta indica extract in rats.

The effects of the ethanol extract of Azadirachta indica stem bark on body and organ weights, sperm morphology, counts and viability, serum levels of testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) were studied in albino rats. Intraperitoneal administration (i.p) of the extract for ten weeks caused significant dose-dependent decreases in weights of the testis, epididymis and seminal vesicles but an increase in that of the adrenal gland. Sperm counts, morphology and viability were adversely affected in the extract treated rats. Rats that received 150 mgkg(-1) b.w. Azadirachta extract were unable to impregnate female rats throughout the duration of the study. However, these female rats conceived and sired physically normal litters about four weeks after cohabitation with untreated male rats. Azadirachta indica produced dose-dependent reduction in serum testosterone and LH but no change in FSH levels. Most of the changes produced in this study were restored in recovery experiments.

Ca++, Mg++-ATPase activity in insulin-dependent and non-insulin dependent diabetic Nigerians.

A study of Ca++, Mg++-ATPase activity was carried out in normal (HHm) and diabetic Nigerians of both sexes with insulin-dependent diabetes mellitus (IDDM) and non-insulin dependent diabetes mellitus (NIDDM). The results showed that protein concentration of erythrocyte ghost membranes of healthy humans (HHm) was the highest when compared with protein concentrations of IDDM and NIDDM patients. The protein concentration was lowest in IDDM, while the value in NIDDM was between those of HHm and IDDM. The basal activities of erythrocyte Ca++-ATPase from IDDM and NIDDM were determined and were found to be significantly lower than that of HHm. The addition of calmodulin (CaM) 2 microg/ml stimulated the activity of the calcium pump in all the groups (IDDM, NIDDM and HHm). The effects of calcium (Ca++) and adenosine triphosphate (ATP) on the activity of the pump from each group were determined. Enzyme kinetics (Km and Vmax) revealed that the activity of Ca++, Mg++-ATPase was initiated by ATP in the presence of Ca++ in a dose-dependent manner. Calmodulin also enhanced the activity of the enzyme in the presence of Ca++ in all the groups, though activities in IDDM and NIDDM were significantly lower than in HHm. There was no significant difference in the activities between IDDM and NIDDM. These results suggest a defective calcium translocating mechanism in diabetic Nigerians.

Antifertility activity of Quassia amara in male rats - in vivo study.

The crude methanol extract of the stem wood of Quassia amara. L. (A-1) significantly caused a reduction in the weight of the testis, epididymis and seminal vesicle, but an increase in that of the anterior pituitary gland. Epididymal sperm counts, serum levels of testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) were significantly reduced when the rats were treated with the extract. Furthermore the basal and LH-stimulated testosterone secretion of Leydig cells isolated from rats pretreated with the extract was inhibited. These changes seemed to be restored eight weeks after the withdrawal from extract treatments. Two compounds - quassin and 2-methoxycanthin-6-one were isolated after fractionation of A-1. Quassin produced similar biological actions as the crude extract while the effects of 2-methoxycanthin-6-one did not seem to differ from those of the control. Quassin appears to be the antifertility principle of Quassia amara.

Blastocyst implantation: effect of thyroidectomy and thyroxine replacement in the rat.

The long term effects of thyroidectomy and chronic thyroxine treatment on blastocyst implantations in female albino rats were studies. Implantation was delayed in both thyroidectomized and hyperthyroid rats, as there was no evidence of blastocyst implantation on day 6 of pregnancy. By day 9, when signs of implantation were observed, the number and weights of the implantation sites were significantly reduced in the athyroid and hyperthyroid rats. Both thyroidectomy and chronic thyroxine treatment significantly reduced the fetal sites and increased the incidence of resorptions when compared with the control. It is concluded that a functional thyroid gland is required for normal implantation to occur.

Antifertility activity of Quassia amara: quassin inhibits the steroidogenesis in rat Leydig cells in vitro.

The crude methanol extract of the stem wood of Quassia amara L. inhibited both the basal and LH-stimulated testosterone secretion of rat Leydig cells in a dose-dependent fashion. Fractionation of the extract by chromatography gave quassin (1) and 2-methoxycanthin-6-one (2); compound 1 proved to be the bioactive agent.

Influence of variety of Nigerian rice on experimental peptic ulceration

The susceptibility of rats prefed with five varieties of rice to indomethacin - induced gastric ulceration was studied. The degree of ulceration was significantly higher (P0.001) in rats fed with white polished rice than in any of the two local rice varieties (Tapa and Ofada). Ulceration was significantly lower (P 0.001) in the brown rice-fed rats than with the polished rice-fed rats. This study indicates that the modern milling processes which improve the palatability and digestibility of rice remove most of the required vitamins along with the bran. Lack of these vitamins makes animals susceptible to gastric ulceration

Symptomatology and hormone profile of menopausal Nigerians.

The alterations in the hormonal levels during menopause have been studied in Nigerian women. There is a significant decrease in oestradiol level of early menopausal and late menopausal women while the testosterone level increased (P less than 0.01). The luteinizing hormone (LH) and follicle-stimulating hormone (FSH) showed significant elevation (P less than 0.01). The elevation of FSH is about 14 times higher in early menopausal women and 16 times higher in late menopausal women when compared to the level in the control. LH, however, showed an elevation eight times higher in early menopausal women and 12 times higher in late menopausal women. The level of these hormones, the intensity of climacteric symptoms among menopausal Nigerian women and attainable age of menopause were found to be the same as in Caucasians.

Effects of gonadectomy on indomethacin-induced ulceration and peptic activity in rats.

Castration in rats caused a reduction in the degree of ulceration produced by indomethacin. Compared with the normal intact male rats, the value of the castrated rats was highly significant (18.42 +/- 0.22 compared with 9.58 +/- 0.17) (P less than 0.01). However, the normal intact male rats had a greater degree of ulceration than the female rats at the pro-oestrous (2.33 +/- 0.13) or oestrous (2.97 +/- 0.12) phases. The ovariectomized rats, however, showed no significant reduction (P greater than 0.01) in mean ulcer score when compared with the di-oestrous female rats. The mean value of peptic activity was very high in ovariectomized rats while it was reduced in intact female rats. The ovariectomized rats were more prone to ulceration than intact female rats although the susceptibility increased in rats at di-oestrus.