1,25(OH)2D3以双向方式影响猪前体脂肪细胞增殖分化的研究

1，25（OH）₂D₃是维生素D的主要活性形式，影响人和动物脂肪形成，为探究其在猪脂肪细胞增殖分化中的作用，试验从3~5日龄仔猪皮下脂肪组织分离培养前体脂肪细胞，并以浓度为0、0.1、1、10、100和1 000 nmol/L的1，25（OH）₂D₃分别处理，在培养的0、1、2、4、6、8和10 d采用MTT比色法检测细胞增殖活性；在诱导分化后0、1、2、4、6、8和10 d，以油红O染色提取法和实时荧光定量PCR检测细胞成脂分化及分化标志基因过氧化物酶体增殖物激活受体γ（PPARγ）和脂肪酸合成酶（FAS）表达。结果显示，0.1和1 nmol/L 1，25（OH）₂D₃显著促进猪前体脂肪细胞增殖（P<0.05），而浓度为10~100 nmol/L时则抑制细胞增殖（P<0.05）；0.1和1 nmol/L 1，25（OH）₂D₃显著抑制猪前体脂肪细胞分化（P<0.05），降低PPARγ和FAS mRNA表达水平（P<0.05），但在浓度为10和100 nmol/L时，显著促进猪前体脂肪细胞分化（P<0.05），上调PPARγ和FAS mRNA表达（P<0.05）；浓度达1 000 nmol/L时，可能对细胞有毒性作用。综合以上结果，低浓度1，25（OH）₂D₃促进猪前体脂肪细胞增殖，而通过下调PPARγ表达抑制分化；高浓度1，25（OH）₂D₃抑制猪前体脂肪细胞增殖，通过上调PPARγ表达促进分化。1，25（OH）₂D₃对猪前体脂肪细胞增殖和分化具有双向作用。

1,25(OH)2D3 Affects Proliferation and Differentiation of Porcine Preadipocytes in a Biphasic Manner

As the main active form of vitamin D,1,25(OH)₂D₃ affects adipogenesis of humans and animals,but its role in proliferation and differentiation of porcine adipocytes is unclear.To explore the effects of 1,25(OH)₂D₃ on proliferation and differentiation of porcine preadipocytes,the cells isolated from subcutaneous adipose tissue of 3-5 days piglets were cultured and treated with 0,0.1,1,10,100 and 1 000 nmol/L concentration of 1,25(OH)₂D₃,respectively.The proliferation of preadipocytes cultured for 0,1,2,4,6,8 and 10 d was detected by MTT method.The differentiation and expression levels of PPARγ and FAS mRNA for the preadipocytes at 0,1,2,4,6,8 and 10 d after inducing-differentiation were determined by oil red O staining and Real-time quantitative PCR,respectively.The results showed that 0.1 and 1 nmol/L 1,25(OH)₂D₃ significantly promoted proliferation of porcine preadipocytes (P<0.05),but the concentration of 10-100 nmol/L inhibited the cell proliferation (P<0.05).At the concentration of 0.1 and 1 nmol/L,1,25(OH)₂D₃ markedly inhibited the differentiation of porcine preadipocytes and reduced mRNA expression of PPARγ and FAS (P<0.05).On the contrary,10 and 100 nmol/L 1,25(OH)₂D₃ significantly enhanced differentiation of porcine preadipocytes and increased mRNA expression of PPARγ and FAS (P<0.05).When the concentration was 1 000 nmol/L,it might be toxic to the cells.These results suggested that low concentration of 1,25(OH)₂D₃ could promote the proliferation of porcine preadipocytes,but inhibit differentiation through down-regulating PPARγ expression.High concentration of 1,25(OH)₂D₃ could inhibit the proliferation of the preadipocytes and promote differentiation by up-regulating PPARγ expression.And so,1,25(OH)₂D₃ affected proliferation and differentiation of porcine preadipocytes in a biphasic manner.