Membrana amniótica como curativo biológico na cicatrização de feridas cutâneas com perdas de substância: estudo experimental em ratos

Abstract

Introduction: Extensive skin losses following trauma or surgery are often prone to complications. Several treatments can be useful because these conditions often require costly and invasive treatments with a number of hospitalizations and preparations for grafts. Objective: To assess the use of amniotic membrane (AM), both fresh and preserved in glycerin 98%, as a biological bandage for extensive skin loss induced on the back of rats, observing the contraction of the bleeding areas macroscopically and the scarring (in the inflammatory, granulation, and fibroplasia stages) histologically. Methods: Fifty-six rats were submitted to wound induction on their backs and randomly distributed into four groups: Cont, Col, FM and PM. Group Cont did not receive any treatment, and the wound was left dry and exposed. Group Col received daily exposed treatment with collagenase. Group FM received the fresh amniotic membrane, whereas group PM received the preserved amniotic membrane, both groups remaining exposed without daily bandages. Each group contained fourteen animals, and seven of each group was biopsied on the 6th, 13th, 20th, and 27th days after wound induction, and the remainder were assessed macroscopically on the 1st, 13th, and 27th day. Results: Macroscopically, on the 13th day, there was a significant difference between the injury areas of groups Cont and FM. On the 27th day, the injury area of group FM was significantly larger than in groups Cont and PM. Microscopically, there was no significant difference regarding inflammatory reaction, granulation tissue, giant cell reaction to foreign body, and fibroplasia between any of the groups in any of the scarring stages. Early fibroplasia was different between groups Col and PM, and there were larger necrotic areas in the PM group on the 6th day. Conclusions: FAM triggered a minor closure of raw areas, compared to the other groups. FAM and PAM did not significantly alter the inflammatory healing phases, granulation and organized fibroplasia. The PAM remained the process of angiogenesis even at the present day 20.