| Popis: |
Cultures of human umbilical vein endothelial cells were treated with heparin-corticosteroid combinations to determine effects on cellular growth. Standard proliferation assays, colony formation assays, and cytoflourometric analysis were the methods employed. Dexamethasone (DEX) and hydrocortisone (HC) were inhibitory to growth of HUVEC when EtOH was used as a solvent and fully supplemented medium (20% serum) was employed. When DMSO was the solvent, growth enhancement sometimes occurred when (DEX) was the test steroid; growth inhibition occurred with this steroid when a reduced (1%) serum component was used. Since significant inhibition of cell colony formation in response to DEX administration was observed, the results suggest that low density growth of HUVEC was inhibited by steroid treatment, while higher density growth was facilitated. Cytoflourometric analysis of HUVEC treated with DEX-heparin combinations indicated that this treatment increased cellular size and possibly increased the number of endothelial cells in the S and/or G2-M phases of the cell cycle in early passage HUVEC. Senescent expression was studied in HUVEC using a cell counting method to determine the percentage of senescent cells in these cultures. The effects of culture gender and passage number on senescent expression were determined for various plating densities and passage split ratios. When primary cultures of HUVEC were passed at a 1:10 split ratio and subsequently passed at a 1:5 split ratio, male cultures expressed a greater degree of cellular senescence than to female cultures. When differences in confluent cell density between male and female primary cultures were corrected for by plating at standard density (1.25 x 105 cells/flask), there were no significant differences in total cells, total senescent cells, or percentages of senescent cells between male and female cultures, a phenomenon which was true in both five and seven day assessments. When cultures of both male and female HUVEC were passed at high density (1:4 split ratio), significantly greater senescent expression occurred in later passages vs. earlier passages, an effect not seen when the cultures were passed at a lower density (1:16 split ratio). There was a trend for both male and female cultures passed at a lower density to express less senescence when contrasted with male and female cultures passed at a higher density. The results suggest that cellular density at passage may be more important than gender in the expression of senescence in HUVEC. |
