To investigate the influence of 1, 25(OH)₂D₃(VD₃) on proliferation and differentiation of human preadipocytes in high-glucose condition.

Primary culture of human preadipocytes were divided into 4 groups: the control group, high glucose group, control+ VD₃ group, and high glucose+ VD₃ group. Oil red O staining and extraction with isopropyl alcohol were employed to detect the total amount of fat in different groups. Real-time polymerase chain reaction was used to detect the mRNA levels of vitamin D receptor (VDR), CCAAT/enhancer binding protein a (C/EBPa) and peroxisome proliferator activated receptor gamma (PPARγ) in each group.

Compared with the control group, the fat amount was significantly increased in the high glucose group(0.231±0.033 vs. 0.362±0.045, P=0.037) and high glucose+ VD₃ group(0.231±0.033 vs. 0.358±0.057, P=0.033), decreased in the control+ VD₃ group(0.231±0.033 vs. 0.174±0.029, P=0.016), but no significant difference in the glucose+ VD₃ group(0.362±0.045 vs. 0.358±0.057, P=0.450); VDR mRNA level was decreased in the high glucose group(0.397±0.029 vs. 0.069±0.003, P=0.022), but VD₃ increased the VDR mRNA levels in both the control+ VD₃ group and the high glucose+ VD₃ group(0.397±0.029 vs. 1.103±0.044, P=0.035; 0.069±0.003 vs. 0.152±0.021, P=0.041); the mRNA levels of C/EBPa and PPARγ were up-regulated in the high glucose group(0.135±0.048 vs. 0.788±0.063, P=0.018; 0.498±0.026 vs. 0.795±0.037, P=0.021), VD₃ decreased the PPARγ mRNA level in the control+ VD₃ group(0.498±0.026 vs. 0.237±0.011, P=0.029), but had no significant effect on C/EBPa mRNA(0.788±0.063 vs. 0.843±0.049, P>0.05) and PPARγ mRNA(0.795±0.037 vs. 0.813±0.041, P>0.05) expressions in the high glucose+ VD₃ group or C/EBPa mRNA in the control+ VD₃ group(0.135±0.048 vs. 0.156±0.022, P>0.05).

VD₃ may lose the ability to inhibit the proliferation and differentiation of human preadipocyte due to reduced biological activity when exposed to high-glucose environment in vitro.

Vitamin D; Vitamin D receptor; Obesity; Diabetes mellitus