周期性牵张应力对人椎间盘纤维环细胞合成和分解的影响

Effects of Different Magnitudes of Mechanical Stretch on Human Intervertebral Disc Cells

目的探讨不同牵张应力对体外培养的人椎间盘纤维环细胞合成和分解代谢的影响。方法采用Flexercell Strain Unit对人椎间盘纤维环细胞施加不同拉伸幅度的周期性牵张应力,通过Real-time PCR,蛋白印迹法,免疫组化以及阻断剂等方法,检测细胞合成代谢基因(collagen-1A1,collagen-2A1,aggrecan,versican)和分解代谢基因(MMP-3,MMP-13,ADAMTS-4,ADAMTS-5)在周期性牵张应力下椎间盘纤维环细胞中的表达。结果合成代谢基因中collagen-1A1和collagen-2A1在12%的应力条件下较对照组表达升高,collagen-2A1在18%表达下降,分解代谢基因MMP-13和ADAMTS-5在12%和18%的应变下较对照组表达升高,ADAMTS-4表达随应力拉伸幅度升高而表达增强。ERK1/2的阻断剂U0126,能明显阻断应力诱导的ADAMTS-4的表达,而p38和JNK的阻断剂SP6000125和SB203580阻断应力诱导ADAMTS-4表达作用不明显。结论不同拉伸幅度的牵张应力对椎间盘纤维化细胞的生物学行为的影响不同,其结果可以影响椎间盘的退变。

Objective To investigate the effects of different magnitudes of mechanical stress on human interverte-bral disc degeneration. Methods The human intervertebral disc cells were subjected to different magnitudes of mechanical stress （0, 6%, 12%, or 18%elongation） for 24 h using a Flexercell Strain Unit. The mRNA expressions of anabolic genes （col-lagen-1A1, collagen-2A1, aggrecan and versican） and catabolic genes （MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5） were examined by real-time PCR and Western blot methods. Results The expression levels of collagen-1A1 and collagen-2A1 were increased at 12%of mechanical stress, and collagen-2A1 was decreased at 18%of mechanical stress compared with those of control. The mRNA expressions of catabolic genes, MMP-13 and ADAMTS-5, were increased at 12%and 18%of mechanical stress than those of control. The mechanical stretch induced a magnitude-dependent increase in ADAMTS-4 synthesis, which was finely tuned by stretching-triggered activation of distinct mitogen-activated protein kinase cascades. Specifically, an ERK1/2 specific inhibitor, U0126, significantly inhibited the stretching-induced ADAMTS-4 expression, whereas the inhibitors of p38 and JNK, SP6000125 and SB203580, showed only slightly effect on the stretching-induced ADAMTS-4 expression. Conclusion The different magnitudes of mechanical stretch exhibited different effects on the bio-logical behavior of intervertebral disc cells, which profoundly affects the intervertebral disc degeneration.