Alignment and proliferation of MC3T3-E1 osteoblasts in microgrooved silicone substrata subjected to cyclic stretching

Previous studies have shown that many types of cells align in microgrooves in static cultures. However, whether cells remain aligned and also prolifer ate in microgrooves under stretching conditions has not been determined. We grew MC3T3-E1 osteoblasts in deformable silicone dishes containing microgr ooves oriented in the stretch direction. We found that with or without 4% s tretching, cells aligned in microgrooves of all sizes, with the groove and ridge widths ranged from 1 to 6 mu m, but the same groove depth of about 1. 6 mu m. In addition, actin cytoskeleton and nuclei became highly aligned in the microgrooves with and without 4% cyclic stretching. To further examine whether MC3T3-E1 osteoblasts proliferate in microgrooves with cyclic stret ching, we grew the cells in six-well silicone dishes containing microgroove s in three wells and smooth surfaces in other three wells. After 4% cyclic stretching for 3, 4, and 7 days, we found that cell numbers in the microgro oves were not significantly different (p > 0.05) from those on the smooth s urface (p > 0.05). Taken together, these results show that MC3T3-E1 osteobl asts can align and proliferate in microgrooves with 4% cyclic stretching. W e suggest that the silicone microgrooves can be a useful tool to study the phenotype of MC3T3-E1 osteoblasts under controlled substrate strains. The s ilicone microgrooves can also be useful for delivering defined substrate st rains to other adherent cells in cultures. (C) 2000 Elsevier Science Ltd. A ll rights reserved.