Stimulation of skeletal-derived cell cultures by different electric field intensities is cell-specific

Pulsed electric stimulation, coupled capacitively to different cell cultures of skeletal origin, caused immediate changes in the cellular levels of cyclic AMP and a later enhanced DNA synthesis. Changes both in cyclic AMP level and DNA synthesis were correlated with the strength of the applied electric field. Cultures of calvaria bone cells which contain mainly two cell types, parathyroid hormone responsive cells (osteoblast-like) and prostaglandin E2 responsive cells (fibroblast-like), respond to both low (13 V/cm) and to high (54 V/cm) electric field strength, with no response at intermediate (24 V/cm) field strength. Rat epiphyseal cartilage responded like bone cells both to low and high field intensities, while rat condylar cartilage responded only to the intermediate field strength. Moreover, subcultures of calvaria bone cells, which lost their osteoblastic phenotype expression during subculturing, were responsive only to low field strength. On the other hand, osteoblast-enriched cultures, derived from calvaria bone grown in low calcium, were responsive only to the high field strength. These findings suggest that the response to various electric field intensities is cell-specific and might be used as an additional parameter to characterize cell types. Our study points to the possibility that when exposing a whole organ to an electrical stimulation it is possible to affect specifically only one cell population out of the many cell types existing in the organ.