Dados do Trabalho

Título

Anti-leukotriene effect on the silicone implant capsule contracture: an experimental study

Introdução

A rate of around 40% of capsular contracture may be expected with the association of radiotherapy after breast implant reconstruction. Several strategies have already been tested to prevent capsule contracture with unsatisfactory results. Anti-leukotrienes have been studied as drugs that would be capable to inhibit or minimize capsular contracture after breast alloplastic implants.

Objetivo

To analyze the effect of topical anti-leukotriene (AL) on the formation of capsular contracture associated to irradiation in rats with silicone implants.

Método

A silicone block was implanted in the dorsal region of 20 Wistar rats that were divided into two groups: control (0.9% saline solution injection in the tissue surrounding the implant), and intervention group (10 mg of AL montelukaste - Singulair®, Merck Sharp & Dohme, Campinas, Brazil - injection in the tissue surrounding the implant). Immediately after the surgery the animals were irradiated with a single dose of 9 Gy, delivered in two tangential opposed fields (4.5 Gy/field) to the area of the silicone block, with 160 KV X-rays (25 mAs) produced by a small animal irradiator (Rad Source RS2000, QuastarTM) at a dose-rate of 6 Gy/min. After two months, capsule samples were submitted to histological and gene expression analysis of the proinflammatory biomarkers iNOS, VEGF-a, and MMP-9.

Resultados

No complications were observed during the study period. Histomorphometric analysis showed less inflammatory reaction with 4.4 versus 8.25 inflammatory cells, and lower vascular density, 55.4 versus 81.8, respectively, in the group that used AL and the control group (p < 0.05). Gene expression was also lower in the AL group when compared to the control group: iNOS 0.005 versus 0.013; VEGF-a 0.02 versus 0.34, and MMP-9 0.030 versus 0.036, respectively. However, only VEGF-a presented a statistically significant difference (p = 0.04).

Conclusão

Our findings corroborated the hypothesis that AL anti-inflammatory effect can mitigate chronic inflammatory response and may reduce silicone implant capsule contracture induced by irradiation in a murine model.

Palavras-chave

capsule contracture; radiotherapy; anti-leukotriene