Effects of a static magnetic field on wound healing: results in experimental rat colon anastomoses

Background: Research has shown that pulsed electromagnetic fields (EMFs) promote wound healing in experimental colonic anastomosis; however, the effects of static EMFs in this setting have not been investigated to date. Methods: Fifty male Wistar rats were used. Ten served as controls for mechanical strength testing, and the other 40 underwent descending colon resection and anastomosis. Twenty of these 40 animals (M group) had NeFeB magnets placed in contact with the anastomosis site (magnetic field strength at the site 390 to 420 G). The other 20 animals (sham [S] group) had nonmagnetized NeFeB bars of the same dimensions and weight implanted. Half of the animals in each group were killed and assessed for healing parameters on postoperative day 3 (M3 and S3 groups) and the other half on postoperative day 7 (M7 and S7 groups). Four types of assessment were done: gross healing, mechanical strength, hydroxyproline deposition, and histopathology. Results: There were no differences between the M and S animals with respect to gross healing parameters. The mechanical strength was also not different between groups (23.8 +/- 12.7 and 24.7 +/- 9.6 mm Hg for M3 and S3, respectively; P = .863 and 91.3 +/- 65.4 and 94.8 +/- 55.9 mm Hg for M7 and S7, respectively; P = .902). Similarly, hydroxyproline deposition was not different between groups on postoperative day 3 or day 7. On postoperative day 3, the M group had significantly higher scores than the S group for fibroblast infiltration (2.4 +/- 0.7 vs 1.4 +/- 0.7, respectively; P = .008) and capillary formation (2.5 +/- 0.7 vs 0.9 +/- 0.4, respectively; P < .001). However, these effects were reversed and did not endure by day 7. Conclusions: The study results suggest that static EMF has no effect on experimental colonic wound healing in the rat. (c) 2006 Excerpta Medica Inc. All rights reserved.