The Effect of Pulsed Electromagnetic Fields on the Calcium Metabolism in Cultured Rabbit Chondrocytes

We have previously demonstrated that pulsed electromagnetic fields (PEMF) affect the functional differentiation of rabbit growth plate chondrocytes in culture by enhancing the response of the parathyroid hormone (PTH). In this study, we examined whether the PEMF affect the proliferation of cultured chondrocytes as well as how their effect on the PTH response of the chondrocytes is related to the calcium metabolism. We cultured growth plate chondrocytes isolated from the ribs of young rabbits and treated them with Verapamil, a calcium blocker, under exposure to PEMF (pulsating recurrent burst, an average of 2 gauss). No significant effect on [3H] -thymidine incorporation into DNA synthesis in either the confluent or logarithmic phase was observed under exposure to PEMF. Verapamil: 1) inhibited DNA synthesis dose-dependently, whereas it did not change the level of glycosaminoglycan (GAG) synthesis; and 2) did not alter the level of PTH-dependent GAG synthesis in the presence or absence of PEMF. These findings indicated that PEMF stimuli resulted in the functional differentiation of growth plate chondrocytes by enhancing GAG synthesis in response to PTH, and that this effect was not affected by the change in the concentration of calcium ions