Study On The Lipid Deposition Mechanisms Of Vitamin D Receptor In The Process Of SD Rats Primary Adipocytes Differentiation

Vitamin D receptor(Vitamin D Receptor, VDR) belongs to the nuclear receptor(steroid / thyroid hormone receptor) superfamily, with nuclear receptor(Nuclear VDR, nVDR) and membrane receptor(Membranae VDR, mVDR), which are two forms of VDR. The molecular weight of nVDR and m VDR are about 50 kD and 60 kDa respectively. In vivo, nVDR and mVDR is mainly mediated by cells effect of vitamin D. In the nucleus, Retinoic Acid X Receptor(RXR) and VDR can form heterodimer and bind to the target gene of promoter sub region of the vitamin D response element, through direct or indirect way to activate the downstream target genes expression and mediated regulation of calcium and phosphorus balance in the body, and bone salt deposition, cell proliferation, differentiation and immune system function.However, there is still much controversy in academic circles about whether VDR is expressed in adipocytes. On the one hand, the role of 1,25(OH)2D on the differentiation of adipocytes is different; on the other hand, 1,25(OH)2D also affect the secretion of the fat factor, increase the complexity of 1,25(OH)2D and adipose tissue interaction. Some studies have shown that over expression of VDR can inhibit the differentiation of 3T3L1 precursor cells, but in the body of mice with systemic VDR knock out mice shows that the phenomenon of body fat reduction. Therefore, the role of VDR on adipocytes differentiation and its way are still controversial, it still need to be further verified.In this study, we cultured SD rat primary adipocytes as research material, using immunohistochemical method to detect VDR and lipid deposition in the adipocyte differentiation process changes regulation, using real-time qPCR and Western blot methods to study the effect of primary fat cells VDR. To provide theoretical basis for the prevention and treatment of obesity with 1,25(OH)2D, which is of great significance to the metabolic health of the body.The main results were as follows:(1) VDR is expressed in adipose tissue and the nucleus of adipose derived cells in SD rats;(2) During the differentiation of adipose derived cells, VDR expression first decreased and then increased. In the adipose derived cells monolayer confluence and differentiation to 8 days, the VDR gene and protein expression was the lowest, and then was increased;(3) In the cell lipid drops gradually increased with the change of time and adipogenic genes PPAR? in differentiation of 16 days and VDR expression was significantly difference(p<0.01);(4) VDR may be involved in the process of adipocyte differentiation, and when the cell lipid drops reaching the threshold will feedback regulating the expression of PPAR?, to suppress the cells continue to become fat. But the working of VDR is not by influencing the PPAR? gene mRNA degradation, it may work in direct or indirect way on PPAR? gene promoter region and functions to regulate certain gene expression.