The process of wound-healing has been found to be susceptible to EMFs; not surprisingly, the
nature of the effect depends on both the exposure conditions and the particular EMFs employed (37-
40). One of the first such reports was that of Bassett et al. (37) involving dogs. Electrical circuits,
attached to leg bones that had been surgically fractured, produced a pulsed 65-Hz magnetic field at the
fracture site. After 28 days, the organization and strength of the repair process as judged by the
mechanical strength of the healing callus had increased significantly. We observed an opposite effect
on fracture healing in rats exposed to a full-body vertical electric field of 5 kv/m, 50 Hz (38). Midshaft
fractures were done on the rats following which half the group was exposed to the field and half was
maintained as a control. The rats were housed individually in plastic enclosures maintained in wooden
exposure assemblies (see Figures 8.2 and 8.3). The extent of healing was evaluated at 14 days
postfracture on the basis of blind scoring of serial microscopic sections. We used a numerical grading
system that characterized both the healing process as a whole, and its anatomical components. In two
replicate studies, we found a highly significant retardation in fracture healing (Table 8.7); the fractures
in the exposed rats exhibited the development normally seen in a 10-day fracture. We found no effect
on fracture-healing following exposure at 1 kv/m. The adverse effect of a 60 Hz electric field on
fracture healing in the rat was confirmed by Phillips in three replicate studies (39).
Table 8.7. HISTOLOGICAL GRADINGS OF RATS EXPOSED TO 5 kv/m
There is also a report of a beneficial effect of microwave EMFs on healing (40). Under sterile
conditions, a linear 5-cm wound down to the dermis was made on the backs of guinea pigs. The
wounds were then closed and sutured and the animals were exposed to 4000 ,µW/cm2 and sacrificed
up to I1 days after surgery. Microscopically, the wounds from the exposed animals exhibited a more
advanced stage of healing, and this was confirmed by mechanical testing data; from 30% to 72% more
force was required to re-open the wounds of the animals exposed to the EMF (Table 8.8).
Table 8.8. EFFECT OF EMF EXPOSURE ON THE FORCE REQUlRED TO DISRUPT A SKIN
WOUND
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