| Part1:Effects of Berberine on the Morphology and Function of Isolated Smooth Muscle of Small Intestine in Diabetic Rats at Early StageObjective: To investigate the effects of berberine on the treatment of small intestinal lesions in early diabetic rats.Methods: Male Sprague Dawley rats weighting 180~220 g were randomly divided into control group,diabetic model group,berberine treated group.The rats were administered by intraperitoneal injection of streptozotocin(STZ,60 mg·kg-1)to establish the diabetic rats model,blood glucose was taken from the tail vein after 72 hours.Fasting blood glucose values greater than 16.7 mmol·L-1 was regarded as a successful model for the induction of diabetic rats.After 3 days of diabetes success,berberine(BBR,200 mg·kg-1)was administrated by gavage once a day for another 2 weeks in berberine treated group.Using the methods of electric field stimulation(EFS)induced neurogenic contractile response and isometric tension recording with organ bath,analyzed the contractile function of isolated small intestinal smooth muscle.HE staining of paraffin sections were performed to observe the changes of intestinal and mesenteric morphology.The effects of berberine on prevention were investigated on intestinal lesions in early diabetic rats.Results:1 The changes of body weight and blood glucose of rats in each groupCompared with the contemporaneous rats,the body weight was significantly decreased in both diabetic group and berberine treated group(P<0.01).There were no significant difference on the body weight in diabetic group and berberine group(P>0.05).Compared with the contemporaneous rats,the blood glucose level was significantly increased in both diabetic group and berberine group(P<0.01);there were no significant difference on the blood glucose between two groups(P>0.05).2 Effects of berberine by treatment on the contractile response induced by EFS in small intestinal smooth muscle of diabetic ratsThe repeatable,stable and frequency dependent contractile responses of small intestinal smooth muscle were induced by EFS,there were no significant difference in contraction response among control,diabetic and BBR treated rats.The contractile responses of small intestinal smooth muscle were abolished by 1 ?mol·L-1 atropine 0.1 ?mol·L-1 TTX.3 The effects of berberine by treatment on NO neurotransmitter synthesis and cholinergic responsiveness of small intestinal smooth muscle in diabetic ratsAfter 100 mol·L-1 L-NAME administrated in the bath,the stimulation of intestinal smooth muscle contraction induced by EFS showed no significant difference among control,diabetic and BBR treated rats(P>0.05).Administration of 1 ?mol·L-1 neostigmine significantly increased the EFS induced contractile response in smooth muscle of small intestine among control,diabetic and BBR treated rats(P<0.05,P<0.01).The differential response of cholinergic nerve function was observed by EFS induced changes of contractile response after administration of neostigmine.Compared with control rats,the changes of jejunum contraction response in diabetic rats was significantly lower(P<0.01).There was no significant improvement in cholinergic nerve function in diabetic rats after administration of berberine(P>0.05).Conclusions: The jejunum has obvious pathological changes in STZ induced early diabetic rats,which was mainly manifested in the impairment of cholinergic nerve function of the small intestine smooth muscle,but there is no significant changes in the nitrergic nerve.BBR treatment significantly improves the morphological changes of the jejunum and has little effects on impairment in nerves function.Part2: The Effects and Mechanisms of Berberine on Prophylactic Administration of Small Intestinal Lesions in Diabetic RatsObjective:To investigate the effects of berberine on the prevention of small intestinal lesions in early diabetic rats.Methods: Male Sprague Dawley rats weighting 180~220 g were randomly divided into control group,diabetic model group and berberine preventive administered group.The rats were administered by intraperitoneal injection of streptozotocin(STZ,60 mg·kg-1)to establish the diabetic rats model,blood glucose was taken from the tail vein after 72 hours.Fasting blood glucose values greater than 16.7 mmol·L-1 was regarded as a successful model for the induction of diabetic rats.The diabetic model group was divided into diabetes 2 weeks,3 weeks and 4 weeks according to the course of the disease,to investigate the relationship between small bowel lesions and disease development.After 3 days of diabetes success,berberine(BBR,200 mg·kg-1)was administrated by gavage once a day for another 2 weeks in berberine preventive administered group.HE staining of paraffin sections,mesentery method and immunohistochemistry were performed to observe the changes of intestinal and mesenteric morphology and epithelial tight junction protein.The effects of berberine on prevention were investigated on intestinal lesions in early diabetic rats.Results:1 The changes of body weight and blood glucose of rats in each groupCompared with the contemporaneous rats,the body weight was significantly decreased in both diabetic group and berberine treated group(P<0.01).There were no significant difference on the body weight in diabetic group and berberine group(P>0.05).Compared with the contemporaneous rats,the blood glucose level was significantly increased in both diabetic group and berberine group(P<0.01);there were no significant difference on the blood glucose between two groups(P>0.05).2 The lesions of different course on the morphology of small intestine and mesentery,and the effects of BBR by prevention in diabetic ratsThe results of HE staining showed that the jejunum villi of the control rats were arranged neatly and densely,the villous structure was complete,and the goblet cells were clear and plump.In the diabetic rats,the villi were disorderly and broken,and the number of goblet cells was reduced.The changes of morphology were occurred obviously at diabetic 2 weeks,and the histological lesions were aggravated with the prolongation of the disease course.The jejunum submucosa of the control rats was tightly connected with the muscle layer,but in the diabetic rats,the separated phenomenon between submucosa and muscularis were observed.BBR by treatment and prevention administration significantly improved the histopathological changes of jejunum in diabetic rats.Compared with the control rats,the thickness of the inner circular muscle and the outer longitudinal muscle was thicker(P<0.01),and the ratio of the villus glands was decreased in the diabetic rats(P< 0.05).There were no significantly improved in the thickness of muscular layers and the ratio of villus glands in diabetic rats by treated with BBR.But BBR prevention administration decreased the thickness of the longitudinal muscle(P<0.01),and increased the ratio of villus glands in diabetic rats(P<0.05).Under microscope,in the mesentery spreading,the mesenteric fat cells in control rats were large and plump,with many elastic fibers and clear staining.Diabetic mesenchymal adipocytes in the rats of different stages of diabetes were reduced and dense,and the elastic fibers were reduced with blurring.Significant lesions appeared at 2 weeks of diabetes,but no obvious lesions of mesenteric fat cells and elastic fibers were observed in the berberine prophylactic rats,which was similar to the control rats.3 The lesions of different course on the expression of tight junction protein in rat jejunum tissue epithelium and the effects of BBR by preventionImmunohistochemical staining showed that,compared with the control rats,the expressions of tight junction proteins ZO-1 and Occludin were reduced in each group of diabetes,and significant reduced was observed at diabetic 2 weeks.With the prolongation of the course of diabetes,the expressions of tight junction protein ZO-1 were gradually decreased,but there was no significant difference in the expressions of Occludin in diabetes at 2,3,and 4 weeks.Compared with diabetic rats,prevention administration of BBR increased the expressions of ZO-1 and Occludin.Conclusions: In the different stages of STZ-induced diabetes,the jejunal lesions of rats are increased with the prolongation of the disease course.At diabetic 2 weeks,the morphology of jejunum and the expression of tight junction proteins ZO-1 and Occludin in epithelial cells have changed significantly.The lesions of mesenteric adipose tissue and elasticity fibrous are obvious.The prophylactic administration of berberine has obvious preventive effect on the morphological changes of jejunum tissue and the expression of tight junction protein in diabetic rats,and protects the mucosal barrier.At the same time,it also has a good preventive effect on mesenteric fat and elastic fiber lesions. |
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