| Vitamin D not only plays a classical role in regulating the calcium and phosphorus homeostasis, but also in the functions of the body’s immune system and endocrine metabolism. Except that, it could have a therapeutic effect on the metabolism of calcium and phosphorus for cows. STC-1is a glycoprotein hormone, which distributes and expresses in many tissues in mammals. Lots of studies show that STC-1regulates the balance of calcium and phosphorus by promoting the absorption and reabsorption of phosphate but inhibiting the absorption of calcium. As a steroid hormone,1,25(OH)2D3involves in the regulation of the endocrine system, such as inhibiting the rsynthesis and secretion of PTH, regulating the secretion of calcitonin (CT) and so on. But there is few report about the effects on the expression of STC-1in ruminant. In addition,1,25(OH)2D3could have effect on the cell proliferation and apoptosis. When it is used as drug, it has some toxicity to some organs, such as its kidney damage. In summary, the purpose of this experiment is to study the effect of1,25(OH)2D3on STC-1expression in bovine kidney cells and the influence in cells proliferation and apoptosis.In order to study the effect of1,25(OH)2D3on MDBK, the cells we chosed were in logarithmic phase. The RT-qPCR was applied for detect the STC-1mRNA expression after treatment. Then how1,25(OH)2D3played its role in this regulaiton was sutdied by using ActD and CHX which could affcted the transcrption levels and translation levels of STC-1. Lastly, the AO/BE staining and flow cytometry were applied for testing the apoptosis of MDBK and the gene Fas, BaX and Bcl-2was deteced through RT-qPCR.1. Effect of1,25(OH)2D3on expression of STC-1in MDBKThe expression of STC-1was up-regulated significantly in l.Onom/L, l0nmol/L,100mnmol/L groups after1,25(OH)2D3working12h (P<0.01). Except that,within different culturing period, the expression levels of STC-1were higer than conrol group,especially in12h,18h,24h respectively (P<0.01). This promoting effcets on STC-1expression by using1,25(OH)2D3were denpending on the expansion of culturing time and increase of1,25(OH)2D3dosage. The expression of STC-1was up-regulated in the experimental group (4μg/mL ActD+VD) than control group and negative control group(with only ActD).But it showed little difference with positive control group(with only VD). However, both the experimental group(CHX+VD) and positive control group(with only VD) had shown a remarkable up-regulation on the expression of STC-1after culturing2h,4h,8h,24h(P<0.01). Through these test,1,25(OH)2D3could promote STC-1mRNA transcription significantly and up-regulate the protein secretion on a certain extent.2. Effect of1,25(OH)2D3on apoptosis of MDBKThe AO/EB staining showed that, the apoptosis of MDBK siginificantly increased with the1,25(OH)2D3treating time expansion. Flow cytometry results showed that after100nmol/L1,25(OH)2D3treatment, apoptosis rates in different time groups were rising compared to the control group, especially in36h,48h,60h and72h (P<0.01). Different concentrations of1,25(OH)2D3treatment after48h, apoptosis rates had risen compared to the control group, in10nmol/L and100nmo/1L showed significantly (P<0.01).After100nmol/L1,25(OH)2D3treatment, Fas gene expression levels in different time groups were up-regulated in60h and72h significantly (P<0.05); Bax expression levels were up-regulated in12h to60h, and24h,36h and72h showed a significant increase (P<0.01); Bcl-2gene expression levels downregulated between60and72h significantly (P<0.01).Conclusion: This study found that1,25(OH)2D3could up-regulated the STC-1expression mainly through increasing the stability of mRNA transcription. Then,1,25(OH)2D3could induce the apoptosis of MDBK through Fas, BaX and Bcl-2pathology.This study provided a new finding about the regulation of1,25(OH)2D3on STC-1which would play an important role in phosphorus metabolism study. |
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