Erythritol attenuates testicular dysfunction in diabetic rat via suppression of oxidative stress, inflammation and apoptosis.

Hyperglycemia -induced oxidative stress and inflammation have been closely associated with diabetes complications including testicular dysfunction. Conversely, reducing blood glucose and/or use of antioxidant have been associated with reduced diabetes complications. The present study investigated the effect of erythritol (which has both antioxidant and blood glucose lowering function) on diabetes -induced testicular dysfunction in rats. Thirty male Wistar rats (170-200g) were randomly divided into 5 groups: 1) control; 2) erythritol; 3) diabetic; 4) diabetic + erythritol 1000 mg/kg; and 5) diabetic + metformin 300 mg/kg. After 8 weeks of treatment period, blood sample, testes and epididymis were collected for reproductive hormones, biochemical and histological examinations, and sperm analysis respectively. There was a significant (p < 0.05) decrease in sperm count, sperm motility, sperm morphology and serum reproductive hormones (Follicle stimulating hormone (FSH), Leutinizing hormone (LH), testosterone and gonadotropin releasing hormone (GnRH)) of diabetes rat compared to control. Also, diabetes rat showed increase in sperm and testicular malonaldehyde (MDA) and decrease in sperm and testicular superoxide dismutase (SOD) activity and glutathione (GSH) level. Further, diabetes rat showed reduced testicular weight, decreased testicular 17ß-HSD and 3ß-HSD activity and testicular histo-architectural alteration which were accompanied by decrease testicular vascular endothelial growth factor (VEGF) and concomitant increase in testicular myeloperoxidase activity and level of caspase 3. The present results indicates that induction of diabetes in rat causes reduction in the level of reproductive hormones (Testosterone, LH and FSH) as well as sperm and testicular oxidative stress causing abnormal sperm parameters, and biochemical and histo-architectural alterations in the testes of rats. In addition, the present results suggest that erythritol administration reduced blood glucose and ameliorated hyperglycemia -induced oxidative stress -mediated alterations in both sperm and testes of diabetes rat. Further, the present study suggests that erythritol improved testicular oxidative stress, inflammation and apoptosis by up-regulating VEGF.

Blood glucose lowering and anti-oxidant potential of erythritol: An in vitro and in vivo study.

Background: Diabetes is a major cause of death worldwide and Nigeria is not an exception. The quest to lower sugar levels has become a major factor in the management of diabetes; this has occasioned the use of substitutes for refined sugar in beverages. Erythritol is a natural sweetener gaining immense interest in recent times. Like metformin, erythritol has shown hydroxyl radical scavenging ability and has metabolic profile suitable for diabetics. Therefore, the blood glucose-lowering and anti-oxidant properties of erythritol under in vitro and in vivo systems were accessed. Methods: Radical scavenging assay (ABTS and DPPH) and inhibition of carbohydrate digestive enzymes (alpha-amylase and alpha-glucosidase) were employed to determine in vitro anti-oxidant and glucose regulatory function of erythritol respectively. Molecular docking studies were performed between 3D structures of human pancreatic alpha-amylase and alpha-glucosidase, isomaltase from saccharomyces cerevisiae with erythritol. The drug-like activity of erythritol was also assessed.Thereafter, we investigated the effect of erythritol on blood glucose and antioxidant status of normal and streptozocin- nicotinamide-induced diabetes rats which were grouped into five (n = 5); Normal, Ery (normal and administered erythritol), Db (diabetic control), Db + Ery (diabetic and administered erythritol), and Db + Met (diabetic and administered metformin). Results: Erythritol showed a considerable radical scavenging activity and an ability to inhibit alpha-amylase and alpha-glucosidase in vitro. Also, a significant reduction in glucose intolerance, blood glucose and hemoglobin A1c levels and improved antioxidant level was seen in erythritol-treated diabetic rats. Conclusion: Erythritol showed anti-oxidant activity, alpha amylase and glucosidase enzyme inhibition property, improved antioxidant status and ameliorated blood glucose, HbA1c, and glucose intolerance following diabetes.

The formalin test : effects of different injection sites on the pattern of nociceptive responses

The formalin test is widely believed to provide a more valid model for clinical pain than tests with phasic mechanical or thermal stimuli. However; the different implementations of the test in use pose the possibility of confounding results. This study evaluated the effects of different injection sites on the pattern of nociceptive responses. The responses to forepaw injection was found to be significantly higher than that of hind paw injection in the first phase while the response to plantar injection was found to be significantly higher than that of dorsal injection. We conclude that the choice of injection site has some effects on the pattern of nociceptive responses

Effects of blood pressure and blood pressure reactivity on experimental pain in healthy females

The study investigated whether the relationship between sex and experimental pain report was explained by blood pressure at rest; or during pain task; or both in healthy; young adult females. Univariate analyses indicated significant positive correlation between baseline systolic blood pressure; systolic blood pressure reactivity; and heart rate reactivity ; but not baseline diastolic blood pressure; diastolic blood pressure reactivity; heart rate; weight; height and pain sensitivity. However none of the positively correlated parameters could significantly predict pain threshold or pain tolerance

Chronic Vitamin C Administration Induces Thermal Hyperalgesia in Male Rats

Against a backdrop of neurological effects; the effects of acute and chronic administration of vitamin C (600mg/kg) on pain processing were investigated in male rats. Chronic administration of vitamin C induced significant thermal hyperalgesia while acute administration had no effect. In addition; the intraperitoneal administration of vitamin C produced observable abdominal writtings similar to what has been observed with acetic acid. We conclude that chronic vitamin C exerts facilitatory central nervous system effects and a possibility of using intraperitoneal injection of vitamin C as an animal model of pain is suggested