Effects Of Rosiglitazone And Tumor Necrosis Factor-α On Mitochondrial Biogenesis And ZAG Expression In Adipocytes

Objective:To observe effects of rosiglitazone and TNF-αon mitochondrial biogenesis and ZAG expression in adipocytes.Methods:3T3-L1 preadipocytes were cultured in vitro and induced to differentiate into matured adipocytes. Adipocytes were treated with different concentrations of rosiglitazone and TNF-αfor 48h respectively. MRNA levels of ZAG, PGC-1α, TFAM, NRF-1/2 genes were detected by RT-PCR. Based on above results, 3T3-L1 adipocytes were randomly divided into four groups: control group, rosiglitazone group (50μM), TNF-αgroup (30ng/mL) and mixed group (rosiglitazone with TNF-αgroup). Expression of mitochondrial biogenesis genes such as PGC-1α, TFAM, NRF-1/2 and ZAG were detected by RT-PCR and Western Blot. Mito Traker Green were used to evaluate the flourescence intensity of mitochondria by laser scanning confocal microscop(LSCM). FFA concentrations in the cell culture supernatants were measured by ELISA.Results:1. Compared with control group, the levels of ZAG, PGC-1α, TFAM, NRF-1/2 genes mRNA expression were increased when mature adipocytes were treated with Rosiglitazone (0.1-50μM) (P<0.01).2. Compared with control group, the levels of ZAG, PGC-1α, TFAM, NRF-2 genes mRNA expression were decreased when mature adipocytes were treated with TNF-α(1-100ng/mL ) (P<0.01). The most significant decline group was the TNF-αgroup (100ng/mL).The levels of NRF-1 mRNA expression were decreased in the TNF-αgroups (10-100ng/mL) (P< 0.01). There was no significant differences between 1ng/mL group and control group (P>0.05). 3. Rosiglitazone (50μM) increased and TNF-αgroup (30ng/mL) decreased the fluorescence of mitochondria in adipocytes.4. 3T3-L1 adipocytes were treated with rosiglitazone (50μM) and TNF-α(30ng/mL) for 48h. Compared with the control group, the levels of ZAG, PGC-1α, TFAM, NRF-1/2 genes mRNA expression were increased in the Rosiglitazone group (50μM) (P<0.01). But mRNA expression of ZAG, PGC-1α, TFAM, NRF-1/2 genes were decreased in the TNF-αgroup (30ng/mL) (P<0.01). Compared with the control group, the level of ZAG,TFAM,NRF-2 genes mRNA expression was increased in the RT group (P<0.01), as the level of NRF-1 mRNA expression was decreased in the RT group (P<0.05). But the level of PGC-1αmRNA expression were no significant differences in the RT group (P>0.05).5. 3T3-L1 adipocytes were treated with rosiglitazone (50μM) and TNF-α(30ng/mL) for 48h. Compared with the control group, the levels of ZAG, NRF-1 and PGC-1α, TFAM proteins expression were increased in the Rosiglitazone group (50μM) (P<0.05 and P<0.01, respectively). And the level of NRF-2 protein expression was no significant difference in this group (P>0.05). The proteins expression levels of ZAG, NRF-1 and TFAM, NRF-2 were decreased in the TNF-αgroup (30ng/mL) (P<0.05 and P<0.01, respectively). And the level of PGC-1αprotein expression was no significant difference in this group (P>0.05). Compared with the control group, the levels of ZAG and PGC-1αproteins expression were increased in the RT group(P<0.01 and P<0.05, respectively) and the level of NRF-2 protein expression was decreased in the RT group (P<0.01).6. Compared with the control group, the FFA concentrations were increased in the TNF-αgroup (30ng/mL) while decreasing in the Rosiglitazone group (50μM) and RT group (P<0.05).Conclusion:1. Rosiglitazone can promote mRNA expression of ZAG, PGC-1α, TFAM, NRF-1/2 genes and proteins expression of ZAG, PGC-1α, TFAM, NRF-1;2. TNF-αcan decrease the mRNA expression of ZAG, PGC-1α, TFAM, NRF-1/2 genes and proteins expression of ZAG, TFAM, NRF-1/2 ;3. Rosiglitazone can recover the mitochondrial function in fatty acid oxidation which lead to the low FFA concentrations. TNF-αcould reduced mitochondrial function in fatty acid oxidation which lead to the high FFA concentrations.