PULSED ELECTROMAGNETIC-FIELDS MODULATE ENZYMATIC-ACTIVITY DURING THE EARLY STAGES OF BONE REPAIR

The goal of this study was to investigate whether PEMFs influence enzy matic activities during the early stages of bone repair. Two transcort ical holes (4.5 mm diameter) were drilled at the same diaphyseal level in the lateral margin of the right and left metacarpal bone (McIII) o f six adult male horses. The left McIII were exposed to PEMFs (75 Hz; 2.8 mT, 1.3 ms impulse width) 24 h/day; the right untreated McIII were used as controls. Horses were sacrificed 8 and 15 days after the oper ation. The bone segments containing the holes were fixed, dehydrated i n ethanol solutions, and, undecalcified, embedded in methylmethacrylat e. The midlongitudinal sections of the holes were either stained with soluidine blue or processed for evaluation of the total alkaline phosp hatase (TRAP) and the tartrate-resistant acid phosphatase (TRAP). In P EMF-treated holes we found: (1) TALP is strongly positive with respect to the controls; (b) the newly formed bony trabeculae are more abunda nt than in the controls; (c) in both treated and control holes, no TRA P-positive osteoclasts were observed on the hole surface, whereas seve ral osteoclasts were located on the newly formed bone tracebulae. On t he basis of these data, it may be concluded that PEMFs accelerate the healing process of transcortical holes and enhance the enzymatic activ ity of repair tissue.