Effects Of DEHP On Glucose Metabolism And Its Mechanisms In Adolescent Rats

Objective:With the development of social economy and the improvement of people's living standard,the prevalence of diabetes increased year by year,and it was one of the major chronic non-communicable diseases affecting human life and health.The proportion of children and adolescents was gradually expansion,especially type 2 diabetes,and the occurrence of type 2 diabetes and metabolic syndrome is closely linked,studies have suggested that the presence of endocrine disruptors in the environment and other exogenous chemicals can interfere with the normal metabolism of the body,especially the DEHP,as the main representative of the phthalate esters,DEHP as a plasticizer widely used,and it is easy to volatilize and dissolve from the material,so not only pollution to the ecological environment,but also it can enter the body through the air,water,food and other media,and endanger the health of the body.Purpose:To observe the effects of DEHP exposure on glucose metabolism in rats,to understand the expression of insulin receptor,leptin receptor and JAK2-STAT3-SOCS3 pathway-related proteins in liver and pancreas of rats,and to explore the possible mechanism of DEHP-induced glucose metabolism disorder in rats.In order to understand the environmental endocrine disrupting DEHP toxicity,to protect the health of the population to provide a scientific basis for metabolic diseases such as Met S and T2 D research and prevention to provide new ideas.Methods:80 healthy Wistar rats(males and females are half)were randomly divided into four Group according to their sex:(1)the control group(corn oil);(2)low group(5 mg/kg/d DEHP,1/6000 LD50);(3)medium group(50 mg/kg/d DEHP,1/600 LD50);(4)high group(500mg mg/kg/d DEHP,1/60 LD50).After a week of adaptive feeding,the corresponding concentrations of DEHP were prepared with corn oil,and the rats were gavaged once every day at 9:00 am,weighing water,food and body weight,and observing the animals for 28 days.After the end of the exposure,fasting for 12 h,the rats were anesthetized,the heart of blood,centrifuged after collecting serum,and cut the liver and pancreas;with biochemical analyzer to detect fasting blood glucose,ELISA method of serum insulin and leptin levels The HOMA-IR values of adolescent rats were calculated.The pathological changes of liver and pancreas were observed by HE staining.The expression of JAK2,STAT3,SOCS3 and Ob-R were observed by immunohistochemistry The protein was located in the liver and pancreas,and the semi-quantitative protein was analyzed by Image-Pro Plus 6.0 software according to the IOD values of different Group.Real-time quantitative PCR was used to determine m RNA expression of JAK2,STAT3,SOCS3 and Ob-R genes in the liver and pancreas.JAK2,STAT3,SOCS3,Ob-R and IR protein in liver and pancreas were determined by Western Blot and analyzed.Result:1.The general toxicity of DEHP to adolescent rats(1)50mg/kg/d and 500mg/kg/d DEHP exposure group of adolescent rats appeared to be slow,apathetic,loose and dull and accompanied by hair removal,while the control group and 5mg/kg/d DEHP Exposure group of adolescent rats were mentally well,with normal activity and bright fur.(2)50mg/kg/d and 500mg/kg/d DEHP exposure group were significantly lower than 5mg/kg/d DEHP exposure group(P<0.05),and 5mg/kg/d The water intake and body weight of adolescent rats exposed to DEHP exposure group were significantly higher than those of control group(P<0.05).(3)500mg/kg/d DEHP exposure group was significantly higher than that of other Group(P<0.05).There was no significant difference in pancreatic organ coefficient between the two Group(P>0.05).2.Effects of DEHP on blood glucose homeostasis and related hormones in adolescent ratsThe serum fasting glucose,serum insulin,serum leptin and HOMA-IR of adolescent rats exposed to 50mg/kg/d and 500mg/kg/d DEHP were significantly higher than those in control group(P<0.05)and 500mg/kg/d DEHP exposure group was significantly higher than 5mg/kg/d DEHP exposure group(P<0.05).3.Effects of DEHP on the morphology of liver and pancreas in adolescent rats(1)Liver: 50mg/kg/d and 500mg/kg/d DEHP exposure group adolescent rat hepatocytes stained shallow,arranged loose,partial edema,cytoplasm is clear,inflammatory cell infiltration and vacuolar changes,and 500mg/kg/d exposure group adolescent rat hepatocytes showed mild necrosis.(2)Pancreas: 50mg/kg/d and 500mg/kg/d exposure group adolescent rat islets decreased relative to the number of scattered,the border is unclear,and the cell volume increased slightly4.Effects of DEHP on m RNA expression of liver and pancreatic related genes in adolescent rats(1)Liver: The expression of Ob-R m RNA in liver of exposed liver was significantly lower than that of 5mg/kg/d DEHP exposure group(P < 0.05);500mg/kg/d DEHP exposure group The expression of SOCS3 m RNA was significantly higher than that of the control group and 5mg/kg/d DEHP exposure group(P<0.05).There was no significant difference in the expression of JAK2 and STAT3 m RNA between the two Group(P>0.05).(2)Pancreatic: 500mg/kg/d DEHP exposure group was significantly lower than that of other Group(P<0.05).The expression of SOCS3 m RNA in pancreas of 500mg/kg/d DEHP exposed group was significantly(P<0.05).The expression of STAT3 gene m RNA in the pancreas of 50mg/kg/d and 500mg/kg/d DEHP exposed group was significantly higher than that in the control group(P<0.05);the expression of JAK2 m RNA in each group was significant difference(P>0.05).5.Effects of DEHP on liver and pancreas associated protein expression in adolescent rats(1)Liver: Immunohistochemical results showed that the expression of Ob-R protein in the liver of 500mg/kg/d DEHP exposed group was significantly lower than that of the control group(P<0.05);50mg/kg/d and 500mg/kg/d DEHP exposure(P<0.05).The expression of JAK2 and STAT3 protein in liver of 500mg/kg/d DEHP exposed group was significantly higher than that of control group(P<0.05).Western Blot results showed that the expression of IR protein in the liver of 500mg/kg/d DEHP exposed group was significantly lower than that in the control group(P<0.05);5mg/kg/d,50mg/kg/d and 500mg/kg/d DEHP exposure group(P<0.05).The expression of SOCS3 protein in the liver of 50mg/kg/d and 500mg/kg/d DEHP exposed group was significantly higher than that in the control group and 5mg/kg(P<0.05).The expression of JAK2 and STAT3 protein in liver of 50mg/kg/d and 500mg/kg/d DEHP exposed group were significantly higher than those in control group(P<0.05).(2)Pancreas: Immunohistochemical results showed that the expression of Ob-R protein in the pancreas of 500mg/kg/d DEHP exposed group was significantly lower than that of other Group(P<0.05);The expression of SOCS3 protein in the pancreas of the 500mg/kg/d and 50mg/kg/d DEHP exposed Group were significantly higher than that of the control group(P<0.05).There was no significant difference in JAK2 and STAT3 protein expression between the two Group(P>0.05).Western Blot results showed that the expression of IR protein in the pancreas of 500mg/kg/d DEHP exposed group was significantly lower than that of the control group and 5mg/kg/d DEHP exposure group(P<0.05);50mg/kg/d and 500mg/kg/d(P<0.05).The expression of SOCS3 protein in the pancreas of 500mg/kg/d DEHP exposed group was significantly higher than that of other Group(P<0.05).The expression of Ob-R protein in the pancreas of DEHP exposed group was significantly lower than that of the control group.The expression of JAK2 and STAT3 protein in pancreas of rats exposed to 500mg/kg/d DEHP were significantly higher than that of control group(P<0.05).Conclusion:(1)Low dose of DEHP exposure may promote the growth and development of adolescent rats,weight gain faster,and high doses of DEHP exposure can slow down adolescent rats weight gain;high doses of DEHP exposure can adolescent rat liver organs increased coefficient.(2)High dose of DEHP exposure will affect the normal glucose metabolism in adolescent rats,disrupting blood glucose homeostasis,causing elevated insulin and leptin levels,the emergence of insulin resistance as a typical symptom of metabolic syndrome.(3)High dose of DEHP exposure can reduce the expression of insulin receptor and leptin receptor in the liver and pancreas of adolescent rats.The receptor signal transduction may be the mechanism of elevated leptin level in adolescent rats induced by high dose of DEHP exposure one(4)High dose of DEHP exposure may increase the expression of SOCS3 m RNA in liver and pancreas,and increase the expression of JAK2,STAT3 and SOCS3 protein in the liver of adolescent rats.As a result of the over expression of SOCS3 receptor-induced signal transduction may be one of the mechanisms of adolescent rats to produce insulin resistance and increase leptin levels.