Effects of risedronate on osteoblastic cell cultures

Bisphosphonates (BPs) have been widely used in the treatment of bone disorders due to their ability to modulate bone turnover. The biological mechanisms through BFs exert their effects on osteoclasts are well established. However, the role of BFs on the osteoblasts is controversial. The present study aimed to evaluate the effects of risedronate on osteoblastic cells.

MC3TE-E1 cells were exposed to risedronate at 0, 10(-8), 10(-6), 10(-4), and 10(-3)M. The following parameters were assayed: (1) cell proliferation by hemocytometer counting after 24, 48 and 72h, (2) cell viability by MTT assay after 24, 48 and 72h, (3) Type I Collagen quantification by ELISA after 24, 48 and 72h, (3) alkaline phosphatase activity after 7 and 10days and (4) matrix mineralization after 14days.

After 24h, risedronate did not affect both cell proliferation and viability (p>0.05). However, after 48 and 72h, a decrease in cell proliferation and viability was detected in osteoblastic cultures exposed to risedronate at 10(-4) and 10(-3)M (p<0.05). After 48 and 72h, Type I Collagen synthesis was stimulated by risedronate at 10(-4)M (p<0.05). High levels of ALP activity were detected in cultures exposed to risedronate at 10(-4)M after 7 and 10days (p<0.05). After 14day, high calcium content was observed in cultures exposed to risedronate at 10(-4)M (p>0.05).

These results indicated that risedronate can promote osteoblast differentiation.