OBJECTIVETo investigate the relationship between inhibitory effect of triamcinolone acetonide(TA) on hypertrophic scar and oxygen free radicals in rabbits.

METHODS18 New Zealand rabbits were used. 14 rabbits were selected randomly to construct animal models of hypertrophic scar on the ears. Another 4 rabbits (8 ears) were used as controls. 6 weeks after operation, the hypertrophic scar on the ears were randomly divided to receive intra-lesion injection of TA (n=10), or normal saline (n=10), or nothing (n=8, sham group). 9 weeks after operation, scar specimens were taken for scar thickness measurement, fibroblast counting under microscopy and MDA content detection by spectrophotometric method.

RESULTS(1) 3 weeks after TA treatment, the scar became very thin and soft with a similar color to normal skin and a smooth surface; (2) Histologic study showed the collagen fibers in TA group were reduced markedly and arranged parallelly; (3) Compared with normal skin, the fibroblast density in sham and saline groups increased significantly (P < 0.05), while it was not markedly different in TA group (P > 0.05). There was also no significant difference in scar hypertrophic index between sham and saline groups (P > 0.05), but the scar hypertrophic index was decreased dramatically in TA group (P < 0.05); (4) The MDA content was highest in TA group (P < 0.05), followed by that in sham and saline groups (P < 0.05), while there was no difference between these two groups (P > 0.05). It was lowest in normal control group (P < 0.05).

CONCLUSIONSThe oxygen free radicals in the hypertrophic scar can be further increased by local injection of TA.