Abnormalities in growth characteristics of aortic smooth muscle cells in spontaneously hypertensive rats.
Comparative studies have shown that cultured vascular smooth muscle cells from spontaneously hypertensive rats (SHR) proliferate to a higher cell number, grow to a greater density, and have greater specific growth rate, particularly at a higher saturation density, than those of the normotensive Wistar-Kyoto (WKY) control rats. The growth difference was not due to varying cell survival nor to attachment ability after passage. The degree of DNA synthesis was estimated by [3H]thymidine incorporation into newly synthesized DNA. [3H]thymidine uptake increased with escalating concentrations of calf serum and reached a plateau at 5% calf serum in WKY rats, whereas an excessive, continuous rise was observed in SHR with up to a 20% concentration. [3H]thymidine incorporation into newly synthesized DNA was tested after stimulation by platelet-derived growth factor and epidermal growth factor. A significantly higher amount of newly synthesized DNA in vascular smooth muscle cells from SHR was noted when the cells were stimulated by platelet-derived growth factor or epidermal growth factor alone, and their simultaneous addition did not significantly change the 50% effective concentration but heightened the maximal response. These data provide evidence of increased aortic smooth muscle cell proliferation from aortas of SHR after mitogen stimulation and suggest a defect in growth stimulatory-inhibitory control.
Hadrava
V
V
Clinical Research Institute of Montreal, Quebec, Canada.
Tremblay
J
J
Hamet
P
P
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000254:growth & development*; D002455:Cell Division; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000494:pharmacology; D006130:Growth Disorders / Q000503:physiopathology; D008297:Male; D024510:Muscle Development; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000254:growth & development*; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D051381:Rats; D013936:Thymidine / Q000378:metabolism; D013997:Time Factors
D010982:Platelet-Derived Growth Factor; D004815:Epidermal Growth Factor; D004247:DNA; D013936:Thymidine