Morphological analysis of three wound-cleaning processes on potentially contamined wounds in rats

Abstract

Purpose:To evaluate the inflammatory response of potentially infected wounds treated with isotonic saline solution, chlorhexidine and PVP-I, seven days after surgery. Methods: Thirty-two male rats were used, divided into 4 groups. All animals had their surgical wounds infected with a standard bacterial inoculum. Control group (A): animals had their surgical wounds sutured without any kind of cleaning. Saline solution group (B): animals had their wounds cleaned with saline solution. Chlorhexidine group (C): animals had their wounds cleaned with chlorhexidine. PVP-I group (D): animals had their wounds cleaned with PVP-I. Seven days after surgery, all the animals had their skin submitted to microscopic and macroscopic evaluation. Results: Edema was found on all histological slices analyzed, as well as vascular proliferation and congestion. Groups A and D showed presence of mild neutrophilic infiltrate, and moderate lymphocytic and macrophage infiltrate. Group B showed severe neutrophilic, macrophage, and lymphocytic infiltrate. Group C showed moderate neutrophilic, macrophage, and lymphocytic infiltrate. Conclusion: Group D was the group which showed inflammatory infiltrate most similar to the group that was not submitted to treatment. Key words: Antisepsis. Chlorhexidine. Povidone-Iodine. Wounds and Injuries. RESUMO Objetivo: Avaliar a resposta inflamatória da limpeza de feridas potencialmente infectadas tratadas com PVP-I, clorexidina e solução salina isotônica, no sétimo dia de pós-operatório, em ratos Wistar. Métodos: Utilizou-se 32 ratos distribuídos em quatro grupos. Os animais tiveram suas feridas operatórias infectadas com um inóculo bacteriano padrão. Grupo controle (A): os animais tiveram suas feridas operatórias suturadas sem a limpeza com qualquer substância. Grupo solução salina (B): os animais tiveram suas feridas operatórias lavadas com solução salina. Grupo Clorexidina (C): os animais tiveram suas feridas operatórias lavadas com clorexidina. Grupo PVP-I (D): os animais tiveram suas feridas operatórias lavadas com PVP-I. Após sete dias foi realizada a avaliação morfológica da pele. Resultados: Em todos cortes histológicos observou-se a presença de edema, proliferação e congestão vascular. O grupo A e D mostraram a presença de um infiltrado neutrofílico discreto, macrofágico e linfocítico moderados. O grupo B, um infiltrado neutrofílico, macrofágico e linfocítico severos. O grupo C, um infiltrado de neutrófilos, macrófagos e linfócitos em moderada quantidade. Conclusão: O grupo D foi o grupo que apresentou o infiltrado inflamatório mais semelhante com o grupo que não recebeu nenhum tratamento.

Action of hyperbaric oxygenation in the rat skin flap

“…The parameters used for microscopic evaluation were based on the criteria described by d'Acampora et al 7 , and by a well-established numerical value we added to the obtained data. These numerical values ranged from 0 to 3, depending on the degree of injury, which are detailed below (Chart 1).…”

Fibroplasia after polypropylene mesh implantation for abdominal wall hernia repair in rats

“…Macrophages were observed on the 2nd day, according to literature data [10][11][12][13]16,22 , reaching their highest levels after the 7th day and remaining high until the end of the study period. This finding differs from classic results, which show that macrophages disappear around the 10th day after mesh implantation 10-13,16,22. Lymphocytes were identified on the polypropylene mesh after the 2nd day, which is inconsistent with the findings of other studies, which indicate that they often appear in the wound on the 5th day after tissue injury 10 .…”

“…This study allowed to observe that neutrophils were present on the surgical wound up to the 21st day, which is a longer period than that described in the literature [10][11][12][13]22 , indicating persistence of the acute inflammatory process. Macrophages were observed on the 2nd day, according to literature data [10][11][12][13]16,22 , reaching their highest levels after the 7th day and remaining high until the end of the study period.…”

“…These findings are consistent with previously reported ones 15,23,24 . In the healing process classically described for skin wounds [10][11][12][13]22 which is the basis for understanding the repair process of other tissues, neutrophils are the first cells to reach the wounded tissue, appearing approximately 24 hours after injury and remaining there for 3 to 5 days. Macrophages migrate to the wounded area 48 to 96 hours after injury, persisting from the 3rd to the 10th day, constituting the major cell type involved in the control and regulation of wound healing before migration and replication of fibroblasts 10,11,16,22 .…”

“…The fibroplasia process consists of a harmonious and coordinated sequence of cellular and molecular events which interact to promote the repair and reconstruction of damaged tissue [10][11][12][13] . Its extent depends on the level of inflammatory activity, one of the healing stages [14][15][16] , and is a prerequisite for the reconstruction of a mechanically stable abdominal wall.…”