Abstract
Diabetes mellitus (DM) has been shown to enhance oxidative stress, leading to aggravation of cerebral ischemic injury following stroke. In this study, we examined the effects of daily administration of a water-soluble extract from culture medium of Ganoderma lucidum mycelia (WER) on total plasma oxidative stress, antioxidant capacity and activity of antioxidant enzymes (superoxide dismutase and catalase) in the brain of rats with streptozotocin (STZ)-induced diabetes. We also investigated whether WER ameliorates the exacerbation of neuronal damage induced by middle cerebral artery occlusion (MCAO) followed by reperfusion in a diabetic state. Male SD rats were treated with STZ (60 mg/kg, i.p.) and housed for 5 weeks for induction of an experimental diabetic state. WER (1 g/kg) was then administered orally for an additional 2 weeks. DM rats had increased oxidative stress and decreased plasma antioxidant capacity in comparison with non-DM rats. Furthermore, the activity of antioxidant enzymes was decreased in the DM rat brain. DM rats treated with WER showed normal levels of all these parameters. The diabetic state markedly aggravated MCAO/reperfusion-induced neurological deficits and cerebral injury assessed by infarct volume. Treatment with WER markedly improved both of these parameters in diabetic rats. These results show that daily intake of WER relieves the exacerbation of cerebral ischemic injury in a diabetic state, and that this may be attributable to amelioration of augmented oxidative stress.
