1α,25(OH)_2D_3对大鼠关节软骨细胞蛋白聚糖和蛋白聚糖酶代谢的调节作用

Role of 1α,25( OH)_2D_3 in the metabolism of aggrecan and aggrecanase in chondrocytes of rat articular cartilage

目的在细胞水平,探讨1α,25(OH)_2D_3对受到多种促炎症因子干预的大鼠关节软骨细胞蛋白聚糖合成和分解的调节作用。方法分别使用促炎症因子IL-1α、IL-1β及TNF-α对大鼠关节软骨细胞进行炎症诱导,使用不同剂量的1α,25(OH)_2D_3对正常及炎症状态下的软骨细胞进行干预,使用CCK8、流式细胞术分析、real time-PCR及western blot等方法分别检测软骨细胞的增殖活性和凋亡水平,以及软骨细胞中蛋白聚糖和蛋白聚糖酶-1/2即ADAMTS-4及ADAMTS-5的mRNA和蛋白表达水平变化,从而评估1α,25(OH)_2D_3对大鼠关节软骨细胞蛋白聚糖和蛋白聚糖酶代谢的调节作用。结果 IL-1α、IL-1β及TNF-α显著降低了软骨细胞的增殖活性并增加了软骨细胞的凋亡水平,以及降低细胞中蛋白聚糖的mRNA和蛋白表达水平,增加ADAMTS-4及ADAMTS-5的mRNA和蛋白表达水平。1α,25(OH)_2D_3的干预可以增加炎症状态下软骨细胞的增殖活性、降低软骨细胞的凋亡水平,以及增加炎症状态下软骨细胞内蛋白聚糖的mRNA和蛋白表达水平,降低ADAMTS-4及ADAMTS-5的mRNA和蛋白表达水平,并呈一定剂量依赖性。但是,1α,25(OH)_2D_3的干预并不影响正常软骨细胞的增殖、凋亡。结论维生素D能促进炎症状态下的软骨细胞蛋白聚糖的合成代谢并抑制蛋白聚糖酶活性,从而为关节软骨提供更全面的保护。

Objective To investigate the role of vitamin D in the synthesis and degradation of aggrecan in rat articular chondrocytes at cellular level. Methods Rat articular chondrocytes were stimulated by IL-1α,IL-1β and TNF-α,respectively. Normal and inflammatory chondrocytes were treated with different doses of vitamin D,respectively.CCK8,Flow cytometry,real time-PCR and western blot analysis were used to examine the proliferation activity and apoptosis level of chondrocytes,and the expression of aggrecan,ADAMTS-4 and ADAMTS-5 at both mRNA and protein levels. Results IL-1α,IL-1β and TNF-α significantly decreased the proliferation activity and increased the apoptosis level of the chondrocytes. Furthermore,IL-1α,IL-1β and TNF-α significantly decreased the expression of aggrecan,and increased the expressions of ADAMTS-4 and ADAMTS-5 at both mRNA and protein levels in the chondrocytes. 1α,25（ OH）2 D3 supplementation significantly increased the proliferation activity and decreased the apoptosis level of chondrocytesstimulated by IL-1α, IL-1β and TNF-α in a dose-dependent manner, but not affected the normal chondrocytes.Meanwhile,1α,25（ OH）2 D3 also significantly increased the expression of aggrecan,and decreased the expressions of ADAMTS-4 and ADAMTS-5 at both mRNA and protein levels in the chondrocytes under inflammatory conditions.Conclusions Vitamin D may promote the anabolism of aggrecan and inhibit aggrecanase activity in chondrocytes under inflammatory conditions,which may impact overall protection for articular cartilage.