Expression Of Perilipin MRNA In Adipose Tissue And The Effects Of Pioglitazone And TNF-a On Its Expression

Objective To observe effect of pioglitazone and TNF-αon perilipin mRNA expression in 3T3-L1 cells and their time-effects. Methods After the 3T3-L1 preadipocytes, differentiating 3T3-L1 cells and differentiated 3T3-L1 adipocytes were incubated with pioglitazone(100umol/l), TNF-α(100ng/ml) for different times,cells were collected,total RNA were extracted .The perilipin mRNA expression were quantitated by semi-quantitative RT-PCR. Results (1) The expression of perilipin mRNA weren't tested in the 3T3-L1 preadipocytes.During differentiation,the perilipin mRNA expression of 3T3-L1 cells were increased along with time.(2)In the differentiated 3T3-L1 adipocytes and differentiating 3T3-L1 cells,treatment of 3T3-L1 cells with 100umol/l pioglitazone increased perilipin mRNA expression compared to untreated controls(P<0.01),the strongest interventional effects of pioglitazone occurred after treating the differentiating 3T3-L1 cells for 8d and differentiated 3T3-L1 adipocytes for 24h respectively.(3) In the differentiated 3T3-L1 adipocytes and differentiating 3T3-L1 cells ,treatment of 3T3-L1 cells with 100ng/ml TNF-αdecreased perilipin mRNA expression compared to untreated controls(P<0.001),the strongest interventional effects of TNF-αoccurred after treating the differentiated 3T3-L1 adipocytes for 72h.(4)Treatment of differentiated 3T3-L1 adipocytes for 48h with 100umol/l pioglitazone alone, 100umol/l pioglitazone and 100ng/ml TNF-α,or with 100ng/ml TNF-αalone, the expression of perilipin mRNA were increased by 78%,decreased by 36% or 78% respectively. Conclusions Along with the cell differentiation,the perilipin mRNA expression are increased in the 3T3-L1 cells.Pioglitazone enhances perilipin mRNA expression in the 3T3-L1 cells,and TNF-αsuppresses that. Pioglitazone attenuates the inhibitory effects of TNF-αon expression of perilipin mRNA in the 3T3-L1 adipocytes. Objective To observe effect of pioglitazone on perilipin mRNA expression in high diet-induced obese rats,and to explore mechanism of pioglitazone intervention insulin resistance. Methods Normal 6-week old male SD rats were divided into three groups randomly. They were normal control group (n = 15) , fat group (n = 15) and pioglitazone- treated fat group (n = 15).Afer 12 weeks high fat diet feeding,fat models were established.Then pioglitazone 10 mg/kg·d was given orally to pioglitazone- treated fat group for 4 weeks.The levels of perilipin mRNA expression in adipose tissue were detected by RT-PCR technique.The serum tumornecrosis factor-a (TNF-a),free fatty acid (FFA), fasting plasma glucose(FPG), fasting insulin ( FINS), triglyceride (TG) were detected in 0,12,16th week. Results (1) High-fat diet induced obesity in SD rats after feeding for 12 weeks. High-fat diet significantly increased levels of TNF-a,FFA,TG,FINS ( P <0.05) and decreased HOMA-IR level ( P < 0.05) as compared with the control group. At the same time, level of perilipin mRNA expression in obese rats was slightly increased as compared with the control group ( P> 0.05) .(2) Pioglitazone caused an apparent reduction of FFA ( - 36 % , P < 0.05),TNF-a ( - 69 % , P < 0.05),FFA ( - 56 % , P < 0.05),TG( - 76 % , P < 0.05) and FINS level ( - 5410 % , P < 0.05).At the same time , pioglitazone increased perilipin by 200 % (P < 0.05) almostly, and improved insulin sensitivity by 49% ( P < 0.05) as compared with the fat group.Conclusions (1) High-fat diet induces insulin resistance in SD rats ; this is associated with an increase in levels of TNF-a,FFA,TG,FINS and a slightly increase in the level of perilipin ; (2) Pioglitazone treatment improves insulin sensitivity accompanied by a reduction of TNF-a,FFA, TG and FINS, and an increase of perilipin mRNA expression.