The Effects Of All-trans Retinoic Acid On The Proliferation,Differentiation And Apoptosis Of Procine Adipocytes

Adipogenesis includes increasing both in amount of and in volume of adipocytes. The adipogenesis or lipolysis result in volume changes of adipocyte. The amount changes of adipcyte include the proliferation, differentiation, apoptosis and dedifferentiation of preadipocyte. During the differentiation process of preadipocyte into mature adipcyte, the temporal expression of a series of genes play an important role. The disregulation of adipocyte differentiation may lead to obesity, diabetes, cardiovascular disease and complications. Studying on the proliferation, differentiation and apoptosis of preadipcoyte, regulating the volume and amount of adipocyte are helpful for decreasing the fat accumulation in domains of animal breeding and feeding.In this paper, through isolating the preadipocyte from the dorsal subcutaneous adipose tissue of 1-3 old days Chang Bai piglets, using MTT method, RT-PCR, Oil red O staining, Oil red O extracting, Acridine Orange fluorescence staining and flow cytometry, we investigate the effects of all-trans Rretinoic Acid (ATRA) on the proliferation, differentiation and apoptosis of preadipocytes.1. The results showed that effect of ATRA is dose-dependent manner on the adipocyte proliferation.10 and 100 nmol/L of ATRA promoted the proliferation(p<0.05), 1,10 and 25μmol/L of ATRA inhibited the differentiation(P<0.05).2. The morphology changes detected by microscopy and ORO staining. The adipogensis and differentiation assayed by ORO extracting.The resuls showed that 10 and 100 nmol/L of ATRA promoted the differentiation(P<0.05), 1, 10 and 25μmol/L of ATRA inhibited the differentiation(P<0.05). The effect of ATRA is dose-dependent manner on the adipocyte differentiation.3. The effects of ATRA on the expression of differentiation-related genes and RARαmRNA on the transcriptional level by semi-quantitative RT-PCR method. The results showed that 10 nmol/L of ATRA decreased the expression of RARαmRNA, but up regulated the expression of LPL, PPARγ2, C/EBPαmRNA, significantly promoting the differentiation(P<0.05) ; 10μmol/L of ATRA up regulated the RARαmRNA level, but down regulated the LPL, PPARγ2 and C/EBPαmRNA levels, significantly inhibiting the differentiation(P<0.05).4. The rate of preadipocyte apoptosis examined by Acridine Orange staining method. The results showed that 10, 25 and 50μmol/L of ATRA can induces the apoptosis of preadipocyte; The results of flow cytometry and semi-quantitative RT-PCR showed that 10μmol/L of ATRA induces the apoptosis of preadipocyte in time-dependent maner, down regulating the expression of apoptosis-related gene Bcl mRNA, and up regulating the apoptosis-promoted gene Bax mRNA expression.