| Objective: To investigate the effect of ethanol extract of Bombax malabaricum skin on blood glucose and lipid in diabetic mice,as well as the effect on PTP1 B and downstream signaling pathways.Studyed the mechanism of Bombax malabaricum skin on blood glucose regulation in diabetic mice.Methods: The model of diabetes mice were induced by intraperitoneal injection of streptozotocin,and the successful animals were divided into 6 groups,including diabetes model group,metformin positive control group(400mg/kg),high dose Bombax malabaricum group(400mg/kg),middle dose(200mg/kg)and low dose group(100mg/kg).At the same time,the normal group was set up with healthy animals.The mice were given intragastric administration for 5 weeks and observed the general condition of each group.The glucose fasting glucose was measured on the 7th day,14 th day,21 th day,28 th day and 35 th day after administration,and investigated the ability of glucose to stimulate insulin release.OGTT assay was used to determine the glucose tolerance level of animals and evaluated the blood glucose regulation function.After treatment serum samples were collected to anlyze the levels of glucose,insulin,total cholesterol,total triglyceride,low density lipoprotein and high density lipoprotein,and the contents of glycogen and triglyceride in liver.The changes of tissue structure were observed by HE staining.The relative expression of PTP1 B,IRS,AKT and FOXO1 mRNA in liver of diabetic mice were determined by RT-PCR and the relative expression of PTP1 B,IRS-1/pIRS-1,AKT/pAKT protein were determined by Western-bolt.Results:1.Mice in general condition: the diet and urine output were significantly increased in model group of diabetes mice,unresponsive,Bombax malabaricum skin ethanol extract group mice in the above situation were significantly improved.2.After treatment,compared with the diabetes model group,the Bombax malabaricum skin ethanol extract could decrease the fasting blood glucose of diabetic mice,and the blood glucose level of the high dose group was significantly lower than that of the diabetes model group(P<0.001),middle dose group and low dose group also had significant hypoglycemic effects(P<0.001).The levels of serum total cholesterol(P<0.05),serum triglyceride(P<0.05),serum low density lipoprotein(P<0.001)and liver triglyceride(P<0.05)were significantly lower than those in the diabetes model group(P<0.05).The content of liver glycogen was significantly increased(P<0.05),and the content of triglyceride in liver was significantly decreased(P<0.05)than diabetes model group.3.After the administration of glucose,the insulin-stimulated insulin release showed that the levels of insulin secretion in the mice were significantly different under the same glucose stimulation condition,and the percentage of insulin in the high and middle dose group were significantly larger than that in the diabetes model group(P<0.05).4.After treatment,compared with the diabetes model group,the number of islets in the mice was increased,the distribution of cells was regular,the shape was clear and the acinar branches were less.5.Compared with the diabetes model group,the Bombax malabaricum skin ethanol extract group could significantly increased the relative expression of IRS mRNA(P<0.05)and FOXO1 mRNA(P<0.05).The relative expression of PTP1 B mRNA and AKT mRNA were not significantly different between diabetes model group and the Bombax malabaricum skin ethanol extract groups.There was a significant increasing of p IRS-1/IRS-1 protein ratio(P<0.05)as well as pAKT/AKT protein ratio(P<0.05),and the expression of PTP1 B protein was significantly decreased(P<0.05).Conclusion: Ethanol extract of Bombax malabaricum skin can significantly reduce the blood glucose level of diabetic mice,alleviating the state of lipid metabolism disorders,repairing tissue injury.Ethanol extract of Bombax malabaricum skin affects insulin signaling transduction by inhibiting activity of PTP1 B,which play an important role in reducing blood glucose and blood lipids in diabetes mice. |
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