Nigerian Journal of Physiological Sciences最新文献

Background: Smoking is associated with dysregulation of the antioxidant system and addiction.

Aim: This study sought to ascertain the effect of Nigella Sativa (NS) oil on the antioxidant system, nicotine/tobacco addiction as well as the expressions of α4β2 nicotinic (nAChR) and dopamine type-2 (DRD2) receptors in selected brain regions of the rat.

Methods: Thirty male Sprague-Dawley rats were divided into 6 groups comprising of vehicle-treated control, NS oil only, Smoke only, Smoke + NS oil, Nicotine only and Nicotine + NS oil. Animals were passively exposed to cigarette smoke or nicotine vapour for 12 weeks, however, NS oil treatment commenced from 9th-12th week of the experimental duration.

Results: Nicotine vapour and cigarette smoke-induced increase in cotinine level were significantly ameliorated by NS treatment. Cigarette smoke or nicotine vapour exposure significantly (p<0.05) decreased the level of antioxidant enzymes while increasing malondialdehyde level in the brain homogenates of the rats.  Administration of NS oil significantly (p<0.05) reversed the reduced antioxidant level. Cigarette-smoke also significantly increased α4-nAChR expression in the frontal cortex and olfactory bulb compared to control. Nicotine vapour significantly increased DRD2 expression only in the olfactory cortex. NS oil administration reduced both the cigarette-smoke-induced increase in α4-nAChR and nicotine vapour-induced increase in DRD2 gene expression only in the olfactory cortex.

Conclusion: Findings from this study suggest that NS oil improves brain antioxidant status while ameliorating nicotine vapour and cigarette smoke addiction through down-regulation of α4-nAChR and DRD2 gene expressions in discrete brain regions in Sprague-Dawley rats.

The African giant rat, AGR (Cricetomys gambianus) is a unique rodent known for its keen sense of smell which has enabled its use in the diagnosis of tuberculosis and demining activities in war torn countries. This keen sense of smell and the ability to navigate tight spaces are skills modulated by the olfactory bulb and cerebellum. While the brain is generally susceptible to environmental pollutants such as heavy metals, vanadium has predilection for these two brain regions. This work was thus designed to investigate the probable neurotoxic effect of vanadium on the neuronal cytoarchitecture of the cerebellum and olfactory bulb in this rodent. To achieve this, twelve adults male AGRs were divided into two groups (vanadium and control groups) and were given intraperitoneal injections of 3mg/kg body weight sodium metavanadate and normal saline respectively for 14 days. After which they were sacrificed, and brains harvested for histological investigations using Nissl and Golgi staining techniques. Results from our experiment revealed Purkinje cell degeneration and pyknosis as revealed by a lower intact-pyknotic cell (I-P) ratio, higher pyknotic Purkinje cell density and poor dendritic arborizations in the molecular layer of the cerebellum in the vanadium treated group. In the olfactory bulb, neuronal loss in the glomerular layer was observed as shrunken glomeruli. These neuronal changes have been linked to deficits in motor function and disruption of odor transduction in the olfactory bulb. This work has further demonstrated the neurotoxic effects of vanadium on the cerebellum and olfactory bulb of the AGR and the likely threat it may pose to the translational potentials of this rodent. We therefore propose the use of this rodent as a suitable model for better understanding vanadium induced olfactory and cerebellar dysfunctions.

Depression is a mental disorder characterized by depressive episodes, such as low mood, low self-esteem, feeling of guilt, and poor concentration. Depression has a high comorbidity with cognitive impairments. Studies have shown that cinnamon has anti-inflammatory antiviral, antihypertensive, antioxidant and anti-diabetic potentials. Therefore, the aim of the research was to assess the antidepressant effect of cinnamon on open-space forced swim-induced depression in mice. Twenty-five (25) Swiss albino mice were grouped into five groups (n=5). Group I: control (negative control) exposed to open-space forced swim test (OSFST) without any treatment, Groups II, III and IV received graded doses of Cinnamon 12.5, 25, and 50 mg/kg, group 5 (positive control) received fluoxetine 20 mg/kg orally. The animals were subjected to OSFST, Open Field Test (Line Crossing) and Novel Object Recognition Test (NORT). Administration of cinnamon showed decreased immobility time (behavioural despair) in OSFST compared to control and fluoxetine groups (p < 0.05). However, no statistically significant effect was observed in line crossing (locomotor activity) and the discrimination ratio of NORT (non-spatial short-term memory) between cinnamon administered groups and the control group. In conclusion, cinnamon has shown antidepressant-like effect in open-space forced swim-induced depression in mice. Keywords: Cinnamon, Depression, Cognitive impairment, Immobility time, Behavioural despair.

Dimethyl nitrosamine (DMN), a potent hepatotoxin, exerts carcinogenic effects and induces hepatic necrosis in experimental animals via CYP2E1 metabolic activation, and generation of reactive oxygen species (ROS). Protocatechuic acid (PCA), a plant-based simple phenolic compound and potent antioxidant, has been shown to affect the development of neoplasia in the rat liver and inhibit the initiation or progression phases of most cancers. In this study, the modulatory effects of PCA on DMN-induced hepatotoxicity, oxidative stress, inflammation, and selected phase I xenobiotic metabolizing enzymes were investigated in male Wistar rats. This study assessed biomarkers of hepatic injury (alanine transaminase, aspartate aminotransferase, alkaline phosphatase, and gamma- glutamyl transferase); oxidative stress (hydrogen peroxide concentration, lipid peroxidation, and reduced glutathione levels); measured activities of antioxidant enzymes (catalase, sodium dismutase, glutathione peroxidase, glutathione S-transferase); and inflammation (Tumor necrosis factor (TNF)-α, interleukin-1-Beta (IL-1β) and iNOS). The results of our investigation demonstrated that pretreatment with PCA at 50 and 100 mg/kg body weight p.o. reduced DMN (20 mg/kg bw) i.p. mediated hepatic injury, oxidative stress, and inflammation in a dose-dependent manner. In addition, the activities of phase I metabolizing enzymes were significantly induced except for aminopyrine-N-demethylase in the DMN-treated rats when compared with the DMN alone control group. This induction was also reversed by pre-treatment with PCA. The result of this study suggests that PCA is hepatoprotective against DMN-induced hepatic damage by its ability to suppress oxidative stress, inflammation, and modulate the activities of the selected phase I drug metabolizing enzymes. Thus, PCA may prove useful in combating DMN-induced hepatic damage.

 Cardiovascular diseases are the leading causes of death globally resulting in 17-19 million death every year. The search for an effective medicine to manage cardiovascular disorder without any side effect has led to the use of traditional based medicine. 75% of the world's population has been reported to depend on traditional medicine as their basic form of health care and this has resulted to the use of herbal medicine in the treatment and management of metabolic diseases. The study evaluated the effect of methanolic extract of Ricinus communis on DDVP-induced cardiotoxicity in male Wistar rats. Thirty-two (32) male Wistar rats were randomly divided into four groups of eight (8) rats each. Group A served as control rats, received 10mL/Kg of dimethyl sulfoxide (DMSO) and distilled water solution (vehicle) for six weeks. Group B served as DDVP-induced rats and were exposed to DDVP (15 minutes daily) for 3 weeks without any treatment. Group C rats received DDVP as in group B and then administered 300mg/kg of R. communis extract for 42days. While Group D rats were administered 300mg/kg of R. communis extract daily, for 6 weeks in addition to normal feed and water. Exposure to DDVP caused significant cardiac dysfunction evidence by alteration in cardiovascular variables and electrocardiac function, compromised lipid profile and reduced antioxidant enzymes. However, treatment with methanolic extract of Ricinus communis improved antioxidant defense system, attenuate hemodynamic impairment and left ventricular dysfunction, as well as inhibit lipid peroxidation and prevent hyperlipidemia in rats. In addition, histopathology observation showed that Ricinus communis extract was able to regenerate the myocardial injury caused by exposure to dichlorvos. In conclusion, Ricinus communis exhibited cardioprotective properties and may be a potential remedy for cardiovascular diseases with low risk of toxicity.

Lead (Pb) toxicity constitutes a major health hazard to both humans and animals especially in the developing countries. It is a ubiquitous environmental contaminant found in the air essentially because of unregulated mining and other industrial activities. Lead can be found naturally in the soil thus, contaminating crops for human and animal food, as well as run-off water and air pollution. Intensively and extensively reared domestic chickens are exposed to contamination via inhalation and ingestion of contaminated food materials. Naringin, a product from citrus plant has been described to possess excellent metal chelating ability. Naringin is rich in flavonoid with attendant antioxidant, anti-autophagy, anti-inflammatory, hepatoprotective and cardio-nephroprotective properties. This study was conducted to investigate the hepatoprotective and modulation of oxidative stress in commercial cockerel chickens by Naringin. Thirty-six commercial cockerel chickens were randomly assigned into six groups A-F of six birds each viz: Group A served as control group while groups B, C, and D received Lead acetate at 300 ppm via drinking water continuously till the end of the experiment. In addition, groups C and D were treated with Naringin at 80 mg/kg and 160mg/kg, respectively, via oral gavage for 8 weeks. Groups E and F were administered naringin only at 80mg/kg and 160mg/kg respectively for eight weeks. Pb toxicity induced degenerative changes in the histological sections as well as, higher expression of hepatic caspase 3 as shown by immunohistochemistry. There was increased oxidative stress markers (H2O2, MDA) and depletion of the antioxidant defense system markers SOD, GPx, GSH, and GST. It concluded that Co- treatment with Naringin ameliorated oxidative stress, enhanced antioxidant defense system, reduced the expression of hepatic caspase 3 thus, offering protection against lead acetate-induced derangements in the liver of commercial cockerel chickens.

Epilepsy is a chronic disease of the brain characterized by seizures. The currently available anticonvulsants only treat symptoms with serious adverse drug reactions. Therefore, there is need for new therapeutic intervention that will prevent epileptogenesis with greater therapeutic success. Quercetin (QT) is a flavonoid with known neuroprotective and anti-inflammatory properties. The study aimed to investigate its effects against pentylenetetrazole (PTZ)-induced seizures. Animals were divided into four groups (n = 10). Group 1(control) only received vehicle (10 mL/kg), group 2 received vehicle, groups 3 and 4 received QT 12.5 mg/kg and 25 mg/kg respectively. Sixty minutes after treatments, animals in groups 2 to 4 were injected with sub-convulsive dose of pentylenetetrazole (35 mg/kg, i.p.) on every alternate day (48±2h) for 21 days. The mice were observed for 30 minutes after each PTZ injection for seizure activity. Brain samples were collected for biochemical assays. Administration of PTZ caused significant increase in the intensity of seizures, neuronal degeneration and level of proinflammatory cytokines in animals compared to control. These behavioural alterations were attenuated significantly by QT (12.5 and 25 mg/kg). The PTZ-induced increase in IL-12, TNF-α and IFN-ɣ were significantly reduced by pre-treatment with the QT (12.5 and 25 mg/kg, p.o). Quercetin also reduced neuronal loss compared to control. Quercetin attenuates seizures in kindled mice and reduces neuroinflammation and neurodegeneration. This neuroprotective effect may be attributed to its ability to inhibit inflammatory mediators in the brain.

Acute caffeine exposure had been shown to induce hyperglycemia however; the influence of thyroid hormones on the caffeine-induced hyperglycemia is yet to be established. The present study was therefore designed to investigate the effect of caffeine exposure on blood glucose and hepatic glycogen content in thyroidectomized rats. Sixty adult male Wistar rats were randomly divided into 10 groups as I-X (n=6).  Rats in groups I, III, V, VII and IX were given normal saline, caffeine, prazosin + caffeine, propranolol +caffeine, combined prazosin+ propranolol+caffeine injections respectively while rats in groups  II, IV, VI, VIII and X were thyroidectomized  and treated in similar manner as the normal rats respectively. Surgical removal of the thyroid gland was done in the thyroidectomised groups while sham-operation was done in Normal group to serve as control. After healing and following an overnight fast, the rats were anaesthetized and the femoral vein and carotid artery were cannulated for drug administration and blood glucose measurement respectively. After stabilization, following basal measurements, rats from each group were injected normal saline or caffeine (6mg/kg) while another sets were pre-treated prazosin (0.2 mg/kg), propanolol (0.5 mg/kg) or their combination before caffeine administration. Blood glucose was then monitored for 60 minutes post-injection of caffeine at 5 minutes interval. Liver samples were collected at the end of the observation period for glycogen content determination. Caffeine caused significant increased blood glucose levels in both normal and thyroidectomized rats which were up to 210% and 180% respectively at the peak of their responses. Liver glycogen content of the thyroidectomized rats (3.11 ± 0.20 mg/100g tissue weight) was significantly higher than the normal rats (1.91 ± 0.43 mg/100g tissue weight). These glycogen contents were significantly reduced by caffeine in both normal (0.25 ± 0.04 mg/100g tissue weight) and thyroidectomized rats (1.65 ± 0.16 mg/100g tissue weight) when compared with their controls. The caffeine effects on blood glucose and hepatic glycogen content were abolished by pretreatment with propanolol or a combination of prazosin and propanolol in both normal and thyroidectomized rats but pretreatment with prazosin caused only significant reduction in hyperglycemic response to caffeine. The findings of this study suggest that caffeine-induced hyperglycemia in both normal and thyroidectomized rats are mediated through both alpha and beta adrenoceptors.

Cattle egret (Bubulcus ibis) is a cosmopolitan heron species, with least concern conservation status. There are limited literatures on the anatomy of this bird, especially in relation to its sensory organs, hence we here investigated the gross morphological and histomorphometric features of its tongue. The tongues of twelve healthy juvenile cattle egrets were examined in situ for morphological appearance and gross morphometric measurements were determined ex situ. Routine histology was conducted on the tongue tissue with parameters such as epithelial and lamina propia heights, lingual muscle and entoglossal cartilage heights evaluated. Grossly, the tongue was divided into three parts name; apex, body and the root. It was arrow shaped, conforming to the shape of the beak, with a laryngeal mound bounded caudally by the pharyngeal papillae at its root. A massive entoglossal cartilage formed the core of the cranial apex, ventral body portion, and caudal aspect of the root. Histologically, the lingual mucosa possessed keratinized squamous epithelium in all its divisions, with spinous conical papillae being characteristic of the cranial apical mucosa. The body lingual mucosa possessed foliate papillae on the dorsal aspects, while filiform papillae were prominent in the ventral portions. The lingual root uniquely possessed numerous glandular ducts in its lamina propia as well as localized adipocytes. Overall, the regression analysis data showed that the body weight can be conveniently predicted from tongue parameters. This study has thus provided additional knowledge on the anatomy of the birds and the generated data could prove useful in comparative regional anatomy.

Dermatoglyphic traits are genetically determined and remain constant until death. Dermatoglyphics features are arranged from patterns, minutiae and ridgeology. This study utilized patterns and minutiae details of fingerprints as a means of sexual differentiation amongst the University of Ibadan community. Three hundred and eighty-four (192 males and 192 females) participants from the University of Ibadan community were recruited using multistage sampling technique. Fingerprints were obtained using fingerprint scanner Dermalog LF10, Hamburg, Germany. GraphPad Prism 7.0 was used for the test of mean of variables. Ulnar loop, whorl and radial loop patterns were found to be predominantly distributed in both male and female in that order. However, the arch pattern was significantly different between female and male. The male subjects had significantly higher total finger ridge count (TFRC). All the analysed minutiae were significantly different between male and female except bridge. The arch pattern, TFRC and level 2 details (minutiae) of dermatoglyphics could be used as markers for sexual differentiation.