The growth capacity of cultured vascular smooth muscle cells (VSMC) obtained from the thoracic aorta of 8-week-old male and female spontaneously hypertensive rats (SHR) was compared. Explants from the intima-media complex were cultured in Dulbecco minimum essential medium supplemented with fetal calf serum (10%). The migration of VSMC out of the explants started on day 2 in both sexes but on day 18 the number of explants with VSMC migration was 100 +/- 32 explants/flask in male VSMC and only 24 +/- 5 explants/flask in female ones. The doubling time at the early exponential phase of growth was shorter (13.5 +/- 0.5 h) and the [3H]-thymidine Labelling Index was higher (34.0 +/- 2.3%) in male VSMC than in those from females (19.9 +/- 0.6 h and 23.9 +/- 1.9%, p < 0.01, respectively). The difference in the doubling time became even more apparent in the late exponential phase of growth (male VSMC: 51.8 +/- 2.0 h, female VSMC: 91.5 +/- 5.8 h, p < 0.001). Moreover, at the end of the exponential growth phase, the male VSMC reached significantly higher (p < 0.001) maximum population density than VSMC from females. Our data provide evidence of different growth characteristics of cultured VSMC isolated from male and female SHR aortas.

Institute of Physiology Academy of Sciences of the Czech Republic Prague

Research on Experimental Hypertension in Prague (1966-2009)