Vitamin C supplementation promotes locomotor and exploratory behaviors in male Wistar rats exposed to varying stress models.

Constant exposure to environmental stress has negative behavioral outcomes. Considering the inverse relationship between stress and Vitamin C intake, this study was aimed at investigating variable stress techniques and Vitamin C supplementation on exploratory/locomotor behaviors in male Wistar rats. Twenty-eight male Sprague-Dawley rats (100g-120g) were allotted into four groups (n=7). Control received 10ml/kg distilled water, group two received 100 mg/kg vitamin C, group three was exposed to different models of stress while group four was stressed alongside 100 mg/kg vitamin C. Vitamin C treatments were given orally for 2 weeks. Animals in groups 3 and 4 were stressed every other day with models such as multiple cage changes, exposure to noise, overnight strange objects, overnight wetting of beddings, and immobility. Explorative and locomotor activities were assessed with the open field test, novel object recognition test, and Y maze test using a Logitech camera and ANY-maze software to track the movement of the rats. Cortisol was assayed in the serum using Enzyme-linked Immuno Assay (ELISA) kit. Superoxide Dismutase, catalase, and lipid peroxidase; malondialdehyde (MDA) were also assayed in the serum. The results show that locomotor activities such as distance traveled, average speed, and time spent in the center square was significantly reduced by stress. These activities were improved with the intake of vitamin C compared with stress. Explorative activities such as locomoting around the environment, orientating towards novelty, and touching or sniffing novel objects were significantly increased in the rats on Vitamin C supplements and reduced in the stressed group. In the serum, cortisol level was significantly increased in rats exposed to stress and decreased with Vitamin C intake. Stress also significantly increased MDA and decreased SOD and CAT while vitamin C supplement decreased MDA and increased SOD and CAT. In conclusion, oral intake of vitamin C enhanced explorative/locomotor behavior and increased oxidative stress in rats exposed to different models of stress.

Neuronal Function in Male Sprague Dawley Rats During Normal Ageing.

During normal ageing, there are physiological changes especially in high energy demanding tissues including the brain and skeletal muscles. Ageing may disrupt homeostasis and allow tissue vulnerability to disease. To establish an appropriate animal model which is readily available and will be useful to test therapeutic strategies during normal ageing, we applied behavioral approaches to study age-related changes in memory and motor function as a basis for neuronal function in ageing in male Sprague Dawley rats. 3 months, n=5; 6 months, n=5 and 18 months, n=5 male Sprague Dawley Rats were tested using the Novel Object Recognition Task (NORT) and the Elevated plus Maze (EPM) Test. Data was analyzed by ANOVA and the Newman-Keuls post hoc test. The results showed an age-related gradual decline in exploratory behavior and locomotor activity with increasing age in 3 months, 6 months and 18 months old rats, although the values were not statistically significant, but grooming activity significantly increased with increasing age. Importantly, we established a novel finding that the minimum distance from the novel object was statistically significant between 3 months and 18 months old rats and this may be an index for age-related memory impairment in the NORT. Altogether, we conclude that the male Sprague Dawley rat show age-related changes in neuronal function and may be a useful model for carrying out investigations into the mechanisms involved in normal ageing.

Streptozotocin diabetes and insulin resistance impairment of spermatogenesis in adult rat testis: central vs. local mechanism.

Mammalian reproduction is dynamically regulated by the pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH). These hormones are synthesized in the pituitary gland following stimulation by the gonadotropin-releasing hormone (GnRH) and act by stimulating steroid production and gametogenesis in both males and females. Male adult Sprague-Dawley rats (120 - 140 g) were randomly divided into 7 groups. Group 1 > Control group; fed on normal rat pellets. Group 2 > Streptozotocin group; received a single dose IP injection of streptozotocin 45 mg/kg BW in Na+ citrate buffer pH 4.5. Group 3 > Streptozotocin-insulin treated group; received a single dose IP injection of streptozotocin as in group 2 above and treated with insulin sub-cutaneously. Group 4 > Streptozotocin-ginger treated group; received a single dose IP injection of streptozotocin as in group 2 above and treated with 500 mg/Kg Ginger extract orally. Group 5 > Insulin resistant group; fed ad libitum on a special diet containing 25% fructose mixed with 75% normal rat chow (w/w). Group 6 > Insulin resistant-pioglitazone treated group; fed ad libitum on a special diet as in group 5 above and treated with Pioglitazone 15 mg/kg orally. Group 7 > Insulin resistant-ginger treated group; fed ad libitum on a special diet as in group 4 above, and also treated with 500 mg/Kg Ginger extract orally. Hormonal and tissue biochemistry analyses revealed that both central and local mechanisms are implicated in the impairment of spermatogenesis by diabetes but the hypothalamo-pituitary testicular axis alteration might not likely have a major impact as the local defect on steroidogenesis in the testis. This local defect could also predispose to male hypogonadism, i.e. failure of gonadal function.

Acute oral toxicity test and phytochemistry of some West African medicinal plants.

BACKGROUND: Although there is increased acceptance and utilization of medicinal plants worldwide, many are used indiscriminately without recourse to any safety test. Thus, the need for toxicity tests to determine the safe dose for oral consumption. OBJECTIVE: LD50 and phytochemistry of four medicinal plants of West Africa were investigated. METHODS: Thirty male and non pregnant female Swiss albino mice weighing 20grams each were used for this study. They were divided into the Control (C), Oldenlandia corymbosa L. aqueous leaf-extract treated (OCG), Parquetina nigrescens aqueous leaf extract treated (PNG), Hybanthus enneaspermus aqueous leaf extract treated (HEG), Ficus carica leaf extract treated (FCG) and Sesamum indicum aqueous seeds extract treated group (SIG). Each group except the control was further divided into four sub-groups of six mice each, and were administered orally, graded doses (SI; 1, 2, 4 and 8, PN; 2.5, 5, 10 and 20, OC; 5, 10, 20 and 40, FC; 1, 2, 4 and 8, HE; 4, 8, 16, 32) of the aqueous extract of each plant (g/kg body weight) after 12 hours fasting. RESULTS: The dry aqueous leaf extracts of HE, OC, PN, FC all have dark brown colour and pH ranging from 6.1 to 7.2 while the seed extract of SI has a light brown color with pH of 7.0. Flavonoids, cardiac glycosides, anthocyanosides, saponin, and reducing sugar were present in all extracts, while cyanogenic glycoside was present only in HE. LD50 determination results obtained using Thompson and Finney methods were as follows; OC; 14.14 +/- 0.27 and 10.56 +/- 0.20, PN; 12.60 +/- 0.10 and 13.10 +/- 0.10, HE; 8.14 +/- 0.30 and 8.24 +/- 0.35, FC; 3.36 +/- 0.26 and 4.00 +/- 0.04, SI; 4.00 +/- 0.10 and 3.10 +/- 0.22 respectively (LD50 values are in g/kg body weight. CONCLUSION: The results of this study have provided an oral LD50 from where a safe dose can be chosen for further research into the merits of the consumption of these medicinal plants.

Ascorbic acid and the effect of cigarette smoke on tissues--a preliminary report.

BACKGROUND: Smoke from the average cigarette contains chemicals, which are highly toxic, causing chronic airways diseases in smokers as well as non-smokers exposed to environmental tobacco smoke (ETS). It is associated with an increased risk of developing asthma, pneumonia, bronchitis and cancer. OBJECTIVE: To investigate the effect of ascorbic acid on the degenerative effect of passive cigarette smoke on some vital organs. METHODS: A total of 16 male rabbits divided into four groups (A, B, C, D) of 4 rabbits each, were used. Group A rabbits were exposed to passive cigarette smoke for 45-60 minutes daily; group B was treated similarly but also had 5 mg/g body weight of ascorbic acid daily. Group C had ascorbic acid only and Group D was the untreated control group. After six weeks of the above treatment, the animals were sacrificed for histological investigation of some of their vital organs. RESULTS: Tobacco smoke had deleterious effects on the lungs, testes and kidneys; no significant changes were seen in the liver, brain and.heart. Ascorbic acid appeared to have some attenuating effect on inflammatory processes as observed in the lungs. Varying degrees of hypospermatogenesis were observed in the seminiferous tubules while the epididymis contained no spermatocytes in both groups A and B. CONCLUSION: Ascorbic acid has some attenuating effect on inflammatory processes but it neither stops inflammation (as seen in the lungs) nor declining function (as signified by hypospermatogenesis in the testes). Therefore, it is doubtful that the long-term effects of tobacco smoke can be prevented by the use of ascorbic acid.

Contractile effect of the aqueous extract of Psidium guajava leaves on aortic rings in rat.

Aqueous leaves extract of Psidium guajava significantly and dose-dependently (0.25-2 mg/ml) contracted aorta rings. The effect was evaluated also in presence of nifedipine and phentolamine. The sensitivity of the aortic rings to cumulative doses of P. guajava was significantly enhanced in the presence of phentolamine suggesting that the effect of P. guajava was to a large extent mediated by activation of alpha-adrenoceptor and to a lesser extent by acting via calcium ion channel.

Fourteen days oral administration of therapeutic dosage of some antibiotics reduced serum testosterone in male rats

Fourteen days oral administration of therapeutic dose of Ampicillin (4mg/100g/day); Cloxacillin (6mg/100g/day) and Tetracycline (12mg/100g/day) separately to healthy adult male albino rats significantly reduced their serum testosterone level as assessed by enzyme immunoassay. The control group received equal volume of the vehicle (Normal saline) throughout the period of the treatment. A significant reduction (P0 .05) in testicular and epididymal weight was also produced by Cloxacillin; Cloxacillin and Tetracycline respectively. Ampicillin administration on the other hand significantly reduced (P0 .05) prostrate gland weight. After subjecting the treated animals to a recovery period ranging from 1-2 weeks; during which the drug administration was discontinued; all the animals recovered fully from the antifertility effect of these antibiotics on the serum testosterone level by the end of the second week. A significant recovery in the epididymal; testicular and prostrate gland weight was also recorded in the Cloxacillin and Tetracycline; Cloxacillin; and Ampicillin treated animals respectively. The result suggests that the reversible antifertility effects of these antibiotics were produced via the disruption of testosterone hormone production process. This was also accompanied by reduction in the weight of some of the male reproductive organs

Fourteen Days Oral Administration of Therapeutic Dosage of some Antibiotics Reduced Serum Testosterone in Male Rats

Fourteen days oral administration of therapeutic dose of Ampicillin (4mg/100g/day); Cloxacillin (6mg/100g/day) and Tetracycline (12mg/100g/day) separately to healthy adult male albino rats significantly reduced their serum testosterone level as assessed by enzyme immunoassay. The control group received equal volume of the vehicle (Normal saline) throughout the period of the treatment. A significant reduction (P0 .05) in testicular and epididymal weight was also produced by Cloxacillin; Cloxacillin and Tetracycline respectively. Ampicillin administration on the other hand significantly reduced (P0 .05) prostrate gland weight. After subjecting the treated animals to a recovery period ranging from 1-2 weeks; during which the drug administration was discontinued; all the animals recovered fully from the antifertility effect of these antibiotics on the serum testosterone level by the end of the second week. A significant recovery in the epididymal; testicular and prostrate gland weight was also recorded in the Cloxacillin and Tetracycline; Cloxacillin; and Ampicillin treated animals respectively. The result suggests that the reversible antifertility effects of these antibiotics were produced via the disruption of testosterone hormone production process. This was also accompanied by reduction in the weight of some of the male reproductive organs

Blood pressure and heart rate changes during pregnancy in fructose-fed Sprague-Dawley rats.

Blood pressure and heart rate changes during pregnancy were investigated in fructose-fed (diabetic) Sprague-Dawley rats. A total of 48 pubertal female rats were used. The experimental rats were fed with 25% (w/w) fructose mixed with normal rat chow for minimum period of 3 weeks while the control rats were fed with the normal rat chow. They all had free access to drinking water. Systolic, diastolic and mean arterial blood pressures and the heart rates were measured in both non-pregnant and pregnant control rats and their diabetic counterparts. The results indicate that systolic blood pressures significantly increased progressively during pregnancy in fructose-fed rats as compared with the non-pregnant rats (P < 0.0001) while in the control rats, except for the 2nd trimester sub-group, which had a similar value with the non-pregnant sub-group, the systolic blood pressure (SBP) also, increased steadily. When the diabetic group is compared with the control group, the SBP (in the 2nd trimester sub-groups) was raised from 82.18 +/- 1.26 mmHg in control rats to 112.48 +/- 1.26 mmHg in the diabetic rats (P < 0.0001). Diastolic blood pressure (DBP) progressively increased significantly in the diabetic rats from 63.94 +/- 3.95 mmHg in the non-pregnant sub-group to 91.95 +/- 1.89 mmHg in the 3rd trimester sub-group of the pregnant rats (P < 0.0001). The DBP of the 2nd trimester sub-group of the diabetic rats was significantly raised from 61.88 +/- 4.20 mmHg in the control rats to 89.60 +/- 1.79 mmHg in the diabetic rats (P < 0.0001). In addition, the mean arterial blood pressure (MAP) was significantly raised in the 1st and 2nd trimester of the diabetic rats from 70.61 +/- 3.12 mmHg in the non-pregnant diabetic rats to 96.28 +/- 1.36 mmHg and 97.13 +/- 1.15 mmHg respectively, (P < 0.0001, P < 0.0001). There was a progressive increase in the heart rates, in both control and diabetic groups, from non-pregnant sub-groups to the 3 trimesters of pregnancy. The body weights of the 2 groups of rats increased significantly as pregnancy progressed. These results suggest that fructose-induced diabetes could cause the development of sustained hypertension during pregnancy via the insulin-resistance-hyperinsulinemia-link.

Effect of acute acetyl-l-carnitine treatment on daytime melatonin synthesis in the rat.

The effects of acute treatment of young male rats with 350 mg/kg of acetyl-l-carnitine (ALCAR) at 15.00 hr on the synthesis and secretion of melatonin by the pineal gland and the retinas were studied 1 hr after injection. The pineal N-acetyltransferase (NAT) activity was unchanged when compared with the control. However, there was a non-significant but slight increase in the melantonin content of the pineal glands in the ALCAR-treated rats. The serum level of melantonim in the ALCAR-treated group was significantly higher (P < 0.05) when compared with the control. The melatonin content of the retinas in the ALCAR treated rats was significantly higher than the control (P < 0.03). This result suggests that the high melatonin content in blood 1 hr after treatment with ALCAR was not as a result of the increased synthesis and secretion rate of melatonin by the pineal gland but rather from extra-pineal source, retina.