Paracrine function of cultured aortic endothelial cells in spontaneously hypertensive rats.
BACKGROUND
Vasoconstrictor and vasodilator release from vascular endothelial cells not only regulates vascular tone but also induces vascular smooth muscle cell proliferation.


METHODS
In order to understand the role of vasoconstrictor and vasodilator release in the development of hypertension in spontaneously hypertensive rats (SHR), aortic endothelial cells were isolated and cultured from 4-week-old and 24-week-old SHR (SHR-4 and SHR-24) and age-matched Wistar-Kyoto rats (WKY-4 and WKY-24) used as control. Prostacyclin (PGI2), endothelin-1 (ET-1) and thromboxane A2 (TXA2) release from cultured endothelial cells in the culture medium, were measured after 30 min with or without treatment with acetylcholine, calcium ionophore A23187 or thrombin.


RESULTS
The results showed that there was no significant difference in ET-1 secretion between SHR-4 and age-matched WKY rats, but ET-1 secretion was about twice as high in SHR-24 as in WKY-24. TXA2 secretion was significantly higher in SHR-4 than in WKY-4 and was also higher than in SHR-24, but there was no significant difference between SHR-24 and WKY-24. The secretion of PGI2 was higher in SHR-24 than in WKY-24 and also higher than in SHR-4 and WKY-4. The prostaglandin PGI2 and TXB2 secretions from all groups of cultured VECs treated with various reagents, acetylcholine, calcium ionophore A23187 or thrombin were increased in similar patterns. However, there was no significantly different response between SHR and WKY VECs.


CONCLUSIONS
Similar levels of ET-1 secreted from endothelial cells between SHR-4 and WKY-4 indicated that ET-1 secretion seems not a crucial factor in early hypertension development in SHR. The high level of TXA2 secretion in SHR-4 may involve in early hypertension development in SHR.
Lu
M H
MH
Department of Biology and Anatomy, Cell Biology Laboratory, Clinical Research Center, Tri-Service General Hospital, Taipei, Taiwan, R.O.C.
Chao
Z C
ZC
Chang
L T
LT
Chao
C F
CF
D000818:Animals; D002478:Cells, Cultured; D019332:Endothelin-1 / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D011464:Epoprostenol / Q000378:metabolism; D006973:Hypertension / Q000378:metabolism*; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013928:Thromboxane A2 / Q000378:metabolism
D019332:Endothelin-1; D013928:Thromboxane A2; D011464:Epoprostenol