RESUMO
BACKGROUND:L-type calcium channels, as a kind of voltage-dependent calcium channel, is the main way of extracellular calcium ions into the cell, and play an important role in maintaining cellmorphology and physiological activities, characterized by a large single-channel conductance, slow channel attenuation, and longer duration of channel opening. Previous studies showed that basic fibroblast growth factor can promote the proliferation of chondrocytes cultured in vitro. OBJECTIVE:To explore the effect of the L-type calcium channels on regulating chondrocyte proliferation and differentiation in response to basic fibroblast growth factor with patch-clamp. METHODS:The chondrocytes were harvested from the joints of 3-day-old New Zealand rabbits. The second passage of chondrocytes was divided into experimental group and control group. Chondrocytes were incubated in media containing 10μg/L basic fibroblast growth factor and media alone separately. The opening of L-type calcium channels under the action of basic fibroblast growth factor was detected by patch-clamp. The intracellular calcium concentration was detected with laser confocal microscopy in the chondrocytes after 2 weeks of culture with basic fibroblast growth factor. Chondrocyte proliferation was analyzed by cellTiter kit after 8 days of culture. Type Ⅱ col agen was assessed quantitatively by immunohistochemistrical staining after 10 days of culture. RESULTS AND CONCLUSION:Basic fibroblast growth factor has an inhibitory effect on the opening of the L-type calcium channels, resulting in a decrease in intracellular free calcium concentration (P<0.01). cellnumber was higher after culture with basic fibroblast growth factor than that cultured under conventional condition (P<0.01), and staining area of type II col agen significantly increased (P<0.05). Results verified that basic fibroblast growth factor can maintain intracellular Ca2+concentration at a low level by inhibiting the opening of L-type calcium channels, which can promote the proliferation and differentiation of chondrocytes.