Neuroprotective effect of beta-D-glucan polysaccharide on hyperglycaemia-induced cerebral injury in diabetic animal model

Abstract

An edible mushroom, Aricularia polytricha is used by local Nigerians in managing diabetes-related complications including infertility and diabetic neuropathy, but this age-long practice has been going on without the corresponding clinical trial and acceptable experimentation. β-D-Glucan polysaccharide is a bioactive fractionate of Auricularia polytricha, an edible mushroom with nutritional and therapeutic property. This study was intended to investigate the neuroprotective effect of β-D-Glucan polysaccharide on hyperglycaemia-induced cerebral injury in diabetic Wistar rats. Experimental animals were grouped into four: Group A served as normal control and was placed on distilled water, while groups B, C and D were induced with diabetes using 65 mg/kg bw of streptozotocin (STZ). Diabetic animals in Groups C and D were treated with 120 mg/kg bw and 200 mg/kg bw of β-D-Glucan polysaccharide respectively. Group B served as diabetic control animals. An analysis of oxidative stress markers (superoxide dismutase, catalase and melondialdehyde) was done to estimate serum levels of the markers; histopathological examination was done to determine micro-structural alteration of brain cells; cell quantification was also done to assess the degree of hypertrophy and proliferation of neurons. Statistical analysis was carried out using Analysis of Variance at p<0.05. Results showed that hyperglycaemic ambience induced a significant increase in serum level of oxidative stress markers with a concomitant increase in cell count, volume and mean size. Increase in glial cells aggregation in the cerebral cortex are indicators of cerebral damage in diabetic control animals. However, levels of oxidative stress markers were significantly downgraded following β-D-Glucan polysaccharide administration. Glial cell aggregation and inflammatory infiltrates were also decreased in diabetic models placed on β-D-Glucan polysaccharide when compared to diabetic control animals, indicating reversal in cerebral damage. The present study suggests that β-D-Glucan polysaccharide has neuroprotective effect in diabetes-induced cerebral damage in Wistar rat.