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.

Myenteric neurons and intestinal mucosa of diabetic rats after ascorbic acid supplementation

AIM: To investigate the effect of ascorbic acid (AA) dietary supplementation on myenteric neurons and epithelial cell proliferation of the jejunum of adult rats with chronic diabetes mellitus. METHODS: Thirty rats at 90 d of age were divided into three groups: Non-diabetic, diabetic and diabetic treated with AA (DA) (1 g/L). After 120 d of treatment with AA the animals were killed. The myenteric neurons were stained for myosin-V and analyzed quantitatively in an area of 11.2 mm2/animal. We further measured the cellular area of 500 neurons per group. We also determined the metaphasic index (MI) of the jejunum mucosa layer of about 2500 cells in the intestinal crypts, as well as the dimensions of 30 villi and 30 crypts/animal. The data area was analyzed using the Olympus BX40 microscope. RESULTS: There was an increase of 14% in the neuronal density (792.6 ± 46.52 vs 680.6 ± 30.27) and 4.4% in the cellular area (303.4 ± 5.19 vs 291.1 ± 6.0) respectively of the diabetic group treated with AA when compared to control diabetic animals. There were no signifi cant differences in MI parameters, villi height or crypt depths among the groups.CONCLUSION: Supplementation with AA in the diabetic animal promoted moderate neuroprotection. There was no observation of alteration of the cellular proliferation of the jejunum mucosa layer of rats with chronic diabetes mellitus with or without supplementation with AA.

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.

Toxoplasma gondii causes death and plastic alteration in the jejunal myenteric plexus

AIM:To assess the effects of ME-49 Toxoplasma gondii(T.gondii) strain infection on the myenteric plexus and external muscle of the jejunum in rats.METHODS:Thirty rats were distributed into two groups:the control group(CG)(n = 15) received 1 m L of saline solution orally, and the infected group(IG)(n=15)inoculated with 1 m L of saline solution containing500 oocysts of M-49 T.gondii strain orally.After 36 d of infection,the rats were euthanized.Infection with T.gondii was confirmed by blood samples collected from all rats at the beginning and end of the experiment.The jejunum of five animals was removed and submitted to routine histological processing(paraffin)for analysis of external muscle thickness.The remaining jejunum from the others animals was used to analyze the general population and the NADH-diaphorase,VIPergic and nitrergic subpopulations of myenteric neurons;and the enteric glial cells(S100-IR).RESULTS:Serological analysis showed that animals from the IG were infected with the parasite.Hypertrophy affecting jejunal muscle thickness was observed in the IG rats(77.02±42.71)in relation to the CG(51.40±12.34),P<0.05.In addition,31.2%of the total number of myenteric neurons died(CG:39839.3±5362.3;IG:26766.6±2177.6;P<0.05);hyperplasia of nitrergic myenteric neurons was observed(CG:7959.0±1290.4;IG:10893.0±1156.3;P<0.05);general hypertrophy of the cell body in the remaining myenteric neurons was noted[CG:232.5(187.2-286.0);IG:248.2(204.4-293.0);P<0.05];hypertrophy of the smallest varicosities containing VIP neurotransmitter was seen(CG:0.46±0.10;IG:0.80±0.16;P<0.05)and a reduction of 25.3%in enteric glia cells(CG:12.64±1.27;IG:10.09±2.10;P<0.05)was observed in the infected rats.CONCLUSION:It was concluded that infection with oocysts of ME-49 T.gondii strain caused quantitative and plastic alterations in the myenteric plexus of the jejunum in rats.

Creatine supplementation in trained rats causes changes in myenteric neurons and intestinal wall morphometry

Creatine is widely used by athletes as an ergogenic resource.The aim of this study was to evaluate the infl uence of creatine supplementation on the duodenum of rats submitted to physical training.The number and myenteric neuronal cell bodies as well mucosal and muscular tunic morphometry were evaluated.Control animals received a standard chow for 8 weeks,and the treated ones received the standard chow for 4 weeks and were later fed with the same chow but added with 2%creatine.Animals were divided in groups:sedentary,sedentary supplemented with creatine,trained and trained supplemented with creatine.The training consisted in treadmill running for 8 weeks.Duodenal samples were either processed for whole mount preparations or for paraffi n embedding and hematoxylin-eosin staining for histological and morphometric studies of the mucosa,the muscular tunic and myenteric neurons.It was observed that neither creatine nor physical training alone promoted alterations in muscular tunic thickness,villus height or crypts depth,however,a reduction in these parameters was observed when both were associated.The number of myenteric neurons was unchanged,but the neuronal cell body area was reduced in trained animals but not when training and creatine was associated,suggesting a neuroprotector role of this substance.