[Expression of peroxisome proliferator-activated receptors Y changes with age in vascular smooth muscle cells of spontaneously hypertensive rat].
OBJECTIVE
In order to elucidate the relationship between PPAR-gamma and the development of hypertension, we detected the expression of peroxisome proliferator-activated receptors gamma (PPAR-gamma) in the vascular smooth muscle cells (VSMCs) and the VSMC proliferation of spontaneously hypertensive rats (SHR) at different ages.


METHODS
The expression of PPAR-gamma in the intact vascular tissues of rats at different ages were detected by immunohistochemistry. Aortic VSMCs were cultured. PPAR-gamma mRNA in primary and low-passage cultured VSMCs of various ages were determined by RT-PCR, and proteins were evaluated by immunohistochemistry and age matched Western Blot. Age matched Wistar-Kyoto rats (WKY) were used as control.


RESULTS
This experiment demonstrated that the expression of PPAR-gamma increased with age in the intact aorta tissues of SHR. The expression of PPAR-gamma did not continuously increase in 24w-old SHR when compared with that in 16w-old SHR. No difference between 4w-, 24w-old SHR and age matched WKY was observed, but the expression of PPAR-gamma was greater in 8w- and 16w old SHR than in age matched WKY. In primary and low-passage cultured VSMCs, the expression of PPAR-gamma mRNA and protein increased with age both in SHR VSMCs and WKY VSMCs of 4w, 8w and 16w old, and no difference between 4w- and 24w-old SHR and WKY was noted, but the expression of PPAR-gamma was higher in 8w- and 16w-old SHR than in age matched WKY. PPAR-gamma expression in 24w-old SHR did not increase and it was equal to 16w-old SHR and 24w-old WKY.


CONCLUSIONS
These datas on SHR suggest that the expression of PPAR-gamma changes with age and the development of high blood pressure. PPAR-gamma expression may play a compensatory role in hypertension, but this compensatory action is limited.
Di
Zheng-Li
ZL
Main Laboratory of Environment and Genes Related to Disease, Ministry of Education, Department of Cardiology, Second Hospital, Xi'an Jiaotong University, Xi'an 710004, China.
Niu
Xiao-Lin
XL
Wei
Jin
J
Li
Yong-Qin
YQ
Chen
Gai-Ling
GL
Wang
Nan-Ping
NP
D000367:Age Factors; D000818:Animals; D001011:Aorta / Q000166:cytology; D049109:Cell Proliferation; D002478:Cells, Cultured; D006973:Hypertension / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D047492:Peroxisome Proliferator-Activated Receptors / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D047492:Peroxisome Proliferator-Activated Receptors; D012333:RNA, Messenger