Nigerian Journal of Physiological Sciences最新文献

Over the last three decades, there has been increasing global concern over the public health impacts attributed to direct and indirect environmental pollution, in particular, the global burden of disease. The World Health Organization estimates that, about a quarter of the diseases facing mankind today occur due to prolonged exposure to environmental pollution; the health of 200 million people in lower-income countries is at risk from toxins such as lead and copper or mercury, more than from AIDS, tuberculosis and malaria combined and that, nearly a quarter of deaths in developing countries including Nigeria and Ghana, are linked to pollution. The purpose of the study was to investigate the effects of the ingestion of large dose of copper on the structural stability of collagen molecules, as well as reveal age-dependent differences in the phenomena.  The content of de novo synthesized collagen was determined by hydroxyproline concentration using Stegmann-Staeder's method as modified by Utevskaya and Persky; the nature of intra- and inter-molecular covalent cross-links in collagen matrix was estimated by electrophoretic separation of products of partial thermal denaturation of collagen in polyacrylamide gel. There was intensification of synthesis over degradation in young rats, and that administration of copper led to a decrease in collagen solubility. Effects of copper on the structural stability of collagen appeared mostly in young rats.

Gedunin is a bioactive compound, obtained from Entandrophragma angolense (EA), which has limited therapeutic usefulness due to poor aqueous solubility and first-pass effects. Cyclodextrins are cyclic oligosaccharides that form complexes with poorly soluble compounds, thus enhancing their pharmacological activity. In this article, we evaluated the pharmacological activities of gedunin-2-hydroxypropyl-β-cyclodextrin complex (GCD) in rodents. The antinociceptive activity of GCD (50, 100, 200 mg/kg) and Gedunin (50mg/kg) was tested in acetic acid-induced writhing and formalin-induced paw licking in mice. The anti-inflammatory activity was investigated in carrageenan-induced paw oedema and air pouch inflammation models in rats. Leucocytes counts, Tumour Necrosis Factor-alpha (TNF-α) level, nitric oxide, malondialdehyde, reduced glutathione, and myeloperoxidase enzyme activities were assessed in the air pouch exudate. The GCD (200mg/kg) significantly decreased writhing response, reduced licking duration and decreased oedema compared with gedunin and control. Exudate volume and leucocyte count were significantly reduced by GCD (200 mg/kg), it decreased myeloperoxidase activity and inhibited TNF-α release. The carrageenan-induced GSH depletion, increased malondialdehyde and nitrite levels were significantly reversed by GCD (200 mg/kg) relative to gedunin and control.  The GCD complex demonstrated significant antinociceptive and anti-inflammatory activities relative to gedunin alone via mechanisms associated with inhibition of oxidative stress and inflammation in rodents.

Arsenic compromises the gastrointestinal integrity and function via the body's anti-oxidative system breakdown.  Hence, this study aimed to investigate the effects of tocopherol on redox imbalance and histoarchitectural alterations in rats' gastrointestinal tract exposed to sodium arsenite. Sodium arsenite and graded doses of tocopherol were administered orally into experimental rats assigned to different groups for four weeks concurrently. Redox status assay was done in homogenized samples by spectrophotometry. Parietal cell mass and mucous cell density (stomach), villus height and crypt depth (ileum), goblet cells count, and crypt depth (colon) were evaluated by histomorphometry. Inflammatory cells infiltration was also assessed using a semi-quantitative procedure. Sodium arsenite caused a significant increase in Malondialdehyde and Myeloperoxidase but, decreased Superoxide dismutase, Catalase, Nitric oxide, Glutathione peroxidase, Glutathione, and Glutathione-S-Transferase. Tocopherol treatment reversed the changes (p<0.05) though not largely dose-dependent. Furthermore, tocopherol annulled sodium arsenite-induced increase in parietal cell mass and decrease in mucous cell density in the stomach, decrease in villus height and villus height/crypt depth ratio in the ileum, and decrease in goblets cells and increase in crypt depth in the colon. Moreover, activated inflammatory cell infiltration by sodium arsenite was mitigated by tocopherol. Sodium arsenite provokes not only marked inflammatory cellular infiltration but a focal loss of glands, hyperplasia of crypts, atrophic villi, and hypertrophy of Peyer's patches in the intestines, which are all lessened with tocopherol treatment.  These findings underscore the anti-oxidative properties of tocopherol as a potent dietary factor against sodium arsenite toxicity in the gastrointestinal tract. Keywords: Tocopherol, arsenic, stomach, ileum, colon.

Pregnancy and lactation are usual but stressful physiological conditions accompanied by changes in calcium and phosphate metabolism and their regulatory hormones which may lead to calcium-related disorders in pregnant women. This study aimed to evaluate the changes in serum levels of calcium, phosphate, vitamin D and their regulatory hormones in pregnant and lactating women in Zaria, Nigeria. A cross‑sectional descriptive study was conducted at Ahmadu Bello University Teaching Hospital, Zaria for three (3) months. Blood samples were collected, anthropometric measurements (weight, height and body mass index) of 179 women were taken. Serum calcium, phosphate, vitamin D, parathyroid hormone and calcitonin were determined using standard methods. Data were presented as mean ± SD, analysis was performed using one-way ANOVA and Pearson's correlation analysis. Values were considered significant at p ≤ 0.05. There was a significant decrease in serum calcium concentration (p < 0.01) during the third trimester of pregnancy and lactation. An increase in serum concentration of vitamin D, parathyroid hormone, and calcitonin in the 2nd trimester and a decrease during the third trimester and lactation although not statistically significant when compared with the control. There was a negative correlation between serum calcium concentration and gestational age (r = 0.255) while no correlation between gestational age and serum phosphate concentration. Changes in serum calcium, vitamin D, parathyroid hormone and calcitonin during pregnancy and lactation has been demonstrated suggesting a relationship between calcium metabolism and these hormones at some stages of pregnancy.

Annona muricata (AMC), is a tropical plant species of the Annonaceae family known for its medicinal uses in ameliorating and/or protecting several organs and tissues in the body. In this study we elucidated the influence of the methanol extracts of AMC leaf and stem bark on the biochemical and histological integrity of the colorectum. Different doses (100, 200, 400, 600, and 800mg of extract/kg body weight) of methanol extracts of the leaves and stembark were orally administered to adult male Wistar rats of average weight (100 - 150 g) for 28 days. At the end of the experimental period, the rats were sacrificed and colorectal tissues harvested for analyses. Adenosine triphosphatase (ATPases), lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G6PD) activities, and tissue protein (TP) concentration, were evaluated by colorimetric method using appropriate test kits. The results in the colorectal tissue analysed showed that total ATPase, LDH and G6PD (energy markers) activities increased significantly in the groups which received methanol leaf and stem bark extracts of AMC when compared with control. However, a general decrease was observed in TP and Na+/K+-ATPase activity but there was a twist in Na+/K+-ATPase activity in stem bark doses of 200mg/kg and 400mg/kg which showed significant increases in dose dependent manner when compared with the control. Even though G6PD activity showed fluctuating patterns for both extracts, the highest dose (800mg/kg) reflected the most significant increase when compared with the control. The histology confirmed the toxicological results by the biochemical parameters. Under the condition of this study, we inferred that the methanol leaf and stem-bark extracts of AMC may significantly influence the enzymes by reducing and increasing total ATPase and Na+/K+-ATPase activities depending on the doses and administration should therefore depend on the desired outcome.

The liver and the kidney are one of the vital organs of body. Drug-induced toxicity is one of the most common problems encountered by these organs. The search for an effective medicine to treat this toxicity without any side effects has led to the use of traditional-based medicine. This study evaluated the effect of ethanolic extract of Moringa oleifera seed oil on hepatic and renal markers in dimethyl 2, 2-dichlorovinyl phosphate (DDVP, known as dichlorvos)-exposed Wistar rats. Twenty-one male Wistar rats were randomly divided into three groups of seven animals each. Group A served as the negative control and were not exposed to dichlorvos. Group B served as the positive control and were exposed to dichlorvos for 2 minutes but received no extract. Group C animals were exposed to the dichlorvos and received 300mg/kg of extract (Moringa oleifera seed oil) for 7days before and 21days after exposure. Exposure to DDVP led to a significant increase in hepatic & renal markers, inflammatory markers, decrease in plasma protein and alteration of plasma electrolyte. Moringa oleifera seed oil regulated and significantly enhanced plasma protein, reduced elevated levels of hepatic & renal markers, inflammatory markers in the study sample. In addition, histopathology observation showed that Moringa seed oil was able to regenerate the hepatorenal damage on exposure to dichlorvos. Conclusion: Moringa oleifera seed oil exhibited hepato-protective, nephroprotective properties and could be explored in nutrition and health.

The aqueous calyx extract of Hibiscus sabdariffa (HS) is widely consumed as a beverage in Northern Nigeria and other parts of the world. HS has been reported to lower blood pressure (BP) in animals and man. However, not much is known about the effect of HS on BP in different postures. We tested the hypothesis that HS may lower BP, heart rate (HR) and heart rate-pressure product or double product (DP) by attenuating the discharge of the autonomic nervous system in different postures. Experiments were performed in accordance with the Principles of the Declaration of Helsinki. Following ethical approval and informed consent, BP and HR were measured in different postures (supine, sitting and standing) in apparently healthy human subjects (n=20) before and after (+HS) the oral administration of 15mg/Kg HS. Mean arterial pressure (MAP; taken as representative BP) and DP were calculated. Results are expressed as mean ±SEM. Paired t test and ANOVA with a post hoc Bonferroni test were used for statistical analyses. P<0.05 was considered significant. In the supine position MAP, HR and DP were significantly (P<0.0001 each) reduced in the presence of HS (85.6±1.7mmHg, 72.1±1.1/min and 8716±320mmHg.bpm) compared to its absence (89.6±2.0mmHg, 73.7±1.6/min and 8921±444mmHg.bpm). Similar trends were observed in the sitting position in the presence of HS (85.4±2.7mmHg, 73.7±1.8/min and 9098±345mmHg.bpm vs its absence: 91.4±2.3mmHg, 77.1±1.9/min and 9388±478mmHg.bpm; P<0.0001, P<0.0001 and P=0.007 respectively) and in the standing position (+HS: 89.3±2.0mmHg,         78.1±1.8/min and 10164±230mmHg.bpm vs its absence: 94.3±2.1mmHg, 81.8±2.3/min and 10742±268mmHg.bpm; P<0.0001, P<0.0001 and P=0.007 respectively). In the absence of HS, HR and DP were significantly higher in the standing posture (81.8±2.3/min, 10742±268mmHg.bpm) compared to the sitting (77.1±1.9/min, 9388±478mmHg.bpm; P<0.05 and P<0.0001 respectively) and the supine (73.7±1.6/min, 8921±444mmHg.bpm; P<0.001 each) postures while the BP remained similar. A similar trend was observed across          the three postures in the presence of HS although the parameters were significantly lower. It is concluded that HS lowered BP, HR and DP by modulating autonomic mechanisms through the inhibition of both parasympathetic withdrawal and sympathetic nervous system discharge across the postures. Also the standing posture is associated more with a higher sympathetic nervous system discharge and a higher cardiac oxygen demand and workload than the sitting and supine postures in the absence or presence of HS.

Plasma osmolality (pOsmol) and neurohumoral signals play important roles in the pathophysiology of cardiovascular diseases. Our study investigated the effect of high environmental temperature (HET) on neurohumoral responses and pOsmol in rats fed a high salt diet (HSD), with and without angiotensin II receptor blockade (ARB), using telmisartan.  Fifty-six male 8-week old Sprague-Dawley rats (95-110g) were randomly assigned into seven groups of 8 rats. These included control rats (I) fed with 0.3% NaCl diet (normal diet, ND); salt-loaded rats (II) fed with 8% NaCl (high salt) diet; ND rats (III) exposed to HET (38.5±0.5oC ) 4 hours daily per week; rats (IV) fed with 8% NaCl diet and exposed to HET daily. Others included rats (V) fed with 8% NaCl diet and treated with telmisartan (30mg/kg); ND rats (VI) exposed to HET and treated with telmisartan; rats (VI) fed with 8% NaCl diet, exposed to HET and treated with telmisartan. Plasma angiotensin II, aldosterone, vasopressin and norepinephrine (NE) concentrations were determined by ELISA technique; pOsmol from plasma K+, Na+ and Urea. HSD combined with HET in rats synergistically increased pOsmol (P<0.001) with an associated non-synergistic rise in fluid intake (P<0.001), fluid balance (P<0.001), plasma angiotensin II (P<0.01) and aldosterone (P<0.05), NE (P<0.001) and vasopressin (P<0.05) concentrations compared to control. Telmisartan did not alter pOsmol in all the treated-rats, but normalized fluid intake levels and plasma vasopressin in the rats exposed to either HSD or HEt alone. Prolonged exposure of rats to hot environment exacerbated the effect of excess dietary salt on pOsmol, with no effect on angiotensin II-mediated neurohumoral responses.