RESUMEN
OBJECTIVE: To investigate the relationship between inhibitory effect of triamcinolone acetonide(TA) on hypertrophic scar and oxygen free radicals in rabbits. METHODS: 18 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). CONCLUSIONS: The oxygen free radicals in the hypertrophic scar can be further increased by local injection of TA.