Study On The Change Of Chemerin Expression In 3T3-L1 Preadipocyte Differentiation And The Plasma Chemerin Levels In Newly Diagnosed Patients With Type 2 Diabetes Mellitus

Objective:1.To observe the change of chemerin gene expression in various tissues of mice and in the process of 3T3-L1 preadipocyte differentiation.To explore the relationship between chemerin gene expression and adipocyte differentiation and adipogenesis.2.To investigate plasma chemerin levels in normal controls and newly diagnosed patients with type 2 diabetes mellitus,and explore the possible correlations between chemerin and aspects of metabolic syndrome.Method:1.Culture of 3T3-L1 cells and induction of differentiation were performed in vitro.Total RNA was extracted from several kinds of tissues(liver,adipose tissue,stomach,spleen,kidney,heart and skeletal muscle) of mice and the differential cells at nine time points(0d,0.5d,ld, 2d,4d,6d,8d,10d,12d).Semi-quantitative RT-PCR was performed in order to measure levels of chemerin mRNA.2.Plasma chemerin of 40 normal controls and 40 type 2 diabetic subjects were assessed by ELISA. Meanwhile body mass index(BMI),waist hip ratio(WHR),blood pressure,blood glucose,the serum lipid profile and insulin concentrations were measured.Results:1.(1) While chemerin gene was expressed in liver,adipose tissue,stomach,spleen,kidney,heart and skeletal muscle of mice,it was expressed most highly in adipose tissue,liver,heart and kidney.(2) Chemerin mRNA levels dramatically increased during the process of differentiation of 3T3-LI cells after 2 days of induction.From 2 days to 12 days,there was a significant difference between any two detected time points in the levels of chemerin mRNA except three time points:8～10d, 8～12d,10～12d(P＜0.01).2.(1) Plasma chemerin levels were not significantly different between the two groups.(2) In normal controls, higher chemerin levels in females compared to males were observed (P＜0.05).(3) Plasma chemerin was positively correlated with WHR(r= 0.277,P＜0.05),and with systolic blood pressure(SBP)(r=0.294, P＜0.01).After adjustment for BMI,WHR,chemerin was still correlated with SBP(r=0.247,P＜0.05).(4) General multivariate regression revealed that SBP and WHR were the significantly independent determinants for chemerin(P＜0.05).Conclusion:1.Upregulation of chemerin mRNA was associated with 3T3-L1 preadipocyte differentiation and adipogenesis.Chemerin was a novel adipokine that may contribute to adipocyte differentiation and may be involved in the development of obesity and its related metabolic diseases.2.Plasma chemerin levels were correlated with obesity and blood pressure,which showed that this novel adipokine may play a role in the pathophysiology of obesity,metabolic syndrome and related cardiovascular diseases.