Neuroprotective action of Ginkgo biloba on the enteric nervous system of diabetic rats

AIM: To investigate the effect of Ginkgo biloba extract on the enteric neurons in the small intestine of diabetic rats. METHODS: Fifteen Wistar rats were divided into three groups: control group (C), diabetic group (D) and diabetic-treated (DT) daily with EGb 761 extract (50 mg/kg body weight) for 120 d. The enteric neurons were identified by the myosin-V immunohistochemical technique. The neuronal density and the cell body area were also analyzed. RESULTS: There was a significant decrease in the neuronal population (myenteric plexus P = 0.0351; submucous plexus P = 0.0217) in both plexuses of the jejunum in group D when compared to group C. With regard to the ileum, there was a significant decrease (P = 0.0117) only in the myenteric plexus. The DT group showed preservation of the neuronal population in the jejunum submucous plexus and in the myenteric plexus in the ileum. The cell body area in group D increased significantly (P = 0.0001) in the myenteric plexus of both segments studied as well as in the ileum submucosal plexus, when compared to C. The treatment reduced (P = 0.0001) the cell body area of the submucosal neurons of both segments and the jejunum myenteric neurons. CONCLUSION: The purified Ginkgo biloba extract has a neuroprotective effect on the jejunum submucous plexus and the myenteric plexus of the ileum of diabetic rats.

Diabetic neuropathy: An evaluation of the use of quercetin in the cecum of rats

AIM:To investigate the effect of quercetin supplementation on the myenteric neurons and glia in the cecum of diabetic rats.METHODS:Total preparations of the muscular tunic were prepared from the ceca of twenty-four rats divided into the following groups:control(C),control supplemented with quercetin(200 mg/kg quercetin body weight)(CQ),diabetic(D)and diabetic supplemented with quercetin(DQ).Immunohistochemical double staining technique was performed with HuC/D(general population)/nitric oxide synthase(nNOS),HuC-D/S-100and VIP.Density analysis of the general neuronal population HuC/D-IR,the nNOS-IR(nitrergic subpopulation)and the enteric glial cells(S-100)was performed,and the morphometry and the reduction in varicosity population(VIP-IR)in these populations were analyzed.RESULTS:Diabetes promoted a significant reduction(25%)in the neuronal density of the HuC/D-IR(general population)and the nNOS-IR(nitrergic subpopulation)compared with the C group.Diabetes also significantly increased the areas of neurons,glial cells and VIP-IR varicosities.Supplementation with quercetin in the DQ group prevented neuronal loss in the general population and increased its area(P<0.001)and the area of nitrergic subpopulation(P<0.001),when compared to C group.Quercetin induced a VIP-IR and glial cells areas(P<0.001)in DQ group when compared to C,CQ and D groups.CONCLUSION:In diabetes,quercetin exhibited a neuroprotective effect by maintaining the density of the general neuronal population but did not affect the density of the nNOS subpopulation.