[Effects of aging and hypoxia on the proliferation of cultured rat pulmonary arterial smooth muscle cells].
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, 3H-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 3H-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.
Shen
Dan-tong
DT
Department of Cardiology, Zhujiang Hospital, First Military Medical University, Guangzhou 510282, China. shendantong@hotmail.com
Fu
Xiang-yang
XY
Huang
Qiao-bing
QB
Huang
Xu-liang
XL
Wang
Shi-wen
SW
D000375:Aging / Q000473:pathology*; D000818:Animals; D002453:Cell Cycle; D002455:Cell Division; D015687:Cell Hypoxia / Q000502:physiology*; D002478:Cells, Cultured; D005260:Female; D005434:Flow Cytometry; D007150:Immunohistochemistry; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D011651:Pulmonary Artery / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013936:Thymidine / Q000378:metabolism
D018809:Proliferating Cell Nuclear Antigen; D013936:Thymidine