3T3L1脂肪细胞对大鼠胰岛β细胞功能障碍的影响

Objective To investigate the integrated effects of adipocytes on rat beta-cells, differentiated 3T3L1 adipocytes and rat islet cells co-culture system was established. Methods There were two groups; control group ( SD rat islet cells) and co-culture group (islet cells and 3T3L1 adipocytes co-culture system). Islet cells were obtained for determination of (1) insulin secretion and insulin content; (2) mRNA expressions of GLUT2, GCK and Kir6. 2; (3) protein expressions of IR-β, IRS-1 and their tyrosine phosphorylation leveL Results (1) At low glucose, insulin secretion of co-culture group increased compared with that of control group (0.79±0.35) ng·h-1 · ml-1 islet vs (0.38±0.09 ) ng · h-1 · ml-1 · islet, P = 0. 028 . At high glucose, insulin secretion of those two groups was almost at the same level (P =0.760). Compared with control group (2. 84 ±0.92) , stimulation index (SI, insulin release at high glucose/ low glucose) of co-culture system decreased to (1. 57 ±0. 61, P =0.04). And the insulin content of the both groups was almost at the same level (P=0.102). (2) The mRNA of GCK, GLUT2 and Kir6. 2 in co-culture group downregulated to (0. 27 ±0. 11, P = 0. 01) , (0. 34 ±0. 24, P = 0. 009) and (0.41 ± 0. 09, P = 0. 003) compared with control group (mRNA = 1). ( 3) The protein levels of IR-β, IRS-1 and their tyrosine phosphorylation decreased in co-culture system. Conclusions 3T3L1 adipocytes are involved in beta-cell dysfunction, which may facilitate the development of type 2 diabetes. The effects may be mediated by multiple pathways, which include downregulation of GSIS related gene expressions and suppression of islet cell insulin signaling.

3T3L1 adipocytes induce rat beta-cell dysfunction