衰老和缺氧对培养大鼠肺动脉平滑肌细胞增殖的影响

Effects of aging and hypoxia on the proliferation of cultured rat pulmonary arterial smooth muscle cells

目的探讨衰老及缺氧对体外培养的肺动脉平滑肌(PASMCs)增殖的影响。方法将细胞分为年轻常氧组、老年常氧组、年轻缺氧组、老年缺氧组,应用MTT比色法、3H-TdR掺入法、流式细胞术、免疫组化方法检查细胞的增殖情况。结果同年轻组比较,老年组PASMCs的生长曲线明显抬高,3H-TdR掺入明显增加,进入有丝分裂期的细胞比例明显增加,总蛋白量减少,增殖细胞核抗原(PCNA)增加;同常氧组比较,缺氧组PASMCs的生长曲线明显抬高,3H-TdR掺入先受抑制,后明显增加,进入有丝分裂期的细胞比例明显增加,总蛋白量减少,PCNA增加。结论衰老和缺氧部能直接刺激平滑肌细胞的增殖,衰老的平滑肌细胞受缺氧刺激增殖最为明显。

Objective To study the effects of aging and hypoxia on the proliferative behavior of cultured pulmonary arterial smooth muscle cells (PASMCs). Methods PASMCs isolated from aged (18-24 months) and young (3-4 months) rats were divided, according to the different treatments the cells were subjected to, into young and aged normoxic groups (groups A and B) and young and aged hypoxic groups (groups C and D) respectively. MTT cell proliferation assay, 3 H-TdR incorporation assay, flow cytometriy and immunocytochemical analysis were respectively employed to observe the proliferative behavior. Results Compared with the cells from young rats, PASMCs from aged rats had a higher proliferation rate, more 3 H-TdR incorporation, increased mitotic cell ratio, reduced amount of the total protein, and elevated content of proliferating cell nuclear antigen (PCNA). In comparison with normoxic condition, hypoxia elicited higher proliferation rate of the cells with inhibition of 3H-TdR incorporation that was subsequently increased. Higher percentage of mitotic cells, less total protein amount and increased PCNA were also observed in response to hypoxia. Conclusions Aging and hypoxia may directly induce PASMC proliferation, and in aging PASMCs, the proliferation is the most obvious in response to hypoxic stimulation.