[Increase of Anti-oxidative Capacity during Differentiation of 3T3-L1 Preadipocytes into Adipocytes].

Cells have developed ingenious defense mechanisms in response to oxidative stress. Here, we evaluated changes in anti-oxidative capacity during differentiation of 3T3-L1 preadipocytes into adipocytes. When 3T3-L1 preadipocytes were treated with HO (0.10-2.0 mM) for 21 h, cell viability decreased in response to HO concentration, with an LD of approximately 0.35 mM HO. In the cells undergoing differentiation at 2 and 6 d, LD increased to 1.0 and >2.0 mM HO, respectively. These results indicate that resistance to oxidative stress dramatically increased with progression of differentiation of preadipocytes into adipocytes. Catalase activity and GSH content increased in the differentiated cells at 6 d, whereas superoxide dismutase and glutathione peroxidase activities were slightly lower in adipocytes than in preadipocytes. Moreover, knockdown of catalase or depletion of intracellular GSH enhanced the sensitivity to HO. When GSH was added to the cells depleted of intracellular GSH, the antioxidant capacity recovered. Autophagy was increased in differentiated adipocytes but was not affected by HO treatment. Therefore, these results suggest that the increase in intracellular catalase activity and GSH content played a role in the increased anti-oxidative capacity of differentiated 3T3-L1 adipocytes.