低氧抑制猪肺动脉平滑肌细胞MMP-2和MMP-9的表达

Hypoxia induced down-regulation of MMP-2 and MMP-9 expression in porcine pulmonary artery smooth muscle cells

目的探讨低氧对猪肺动脉平滑肌细胞(PASMC)分泌基质金属蛋白酶(MMPs)的影响。方法采用酶谱法测定PASMC培养基中MMP-2和MMP-9的酶活性,免疫印迹法检测培养基中MMP-2和MMP-9的蛋白表达,免疫组化法测定细胞原位MMP-2和MMP-9的蛋白表达,RT-PCR法检测mRNA的表达。结果低氧后PASMC分泌的MMP-2酶活性、细胞内外蛋白表达量、mRNA表达量均下降;MMP-9酶活性、细胞外蛋白表达量下降,而细胞内蛋白表达无变化。结论低氧可抑制PASMC分泌MMP-2和MMP-9的酶活性,其机制可能是低氧影响PASMC中MMP-2基因的转录、影响MMP-9蛋白表达后的分泌与活化,导致MMP-2和MMP-9酶活性的改变。

Objective To investigate the effect of hypoxia on expression of MMP-2 and MMP-9 in hog pulmonary artery smooth muscle cells（PASMC）. Methods MMP-2 and MMP-9 activity was measured using gelatin zymography, intracellular and extracellular MMP-2, MMP-9 protein was determined by immunocytochemistry and Western blot, mRNA expression was determined by reverse transcriptase-polymerase chain reaction （ RT-PCR）. Results Exposure to hypoxia for 24 h induced down-regulation of MMP-2 mRNA and protein in PASMC, as well as the decrease of MMP-2 activity, and induced the decrease of MMP-9 activity and extracellular protein, but had no effect on MMP-9 intracellular protein expression. Conclusion Hypoxia induced reduction of MMP-2 and MMP-9 activity in PASMC, the main mechanism of alteration of MMP-2 activity was due to reduction of MMP-2 transcription and that of MMP-9 was due to MMP-9 protein secreting and activating.