Healing reaction to mammary prostheses covered by textured silicone and silicone foam in rats

Abstract

Purpose:To compare the capsular reaction to two different coverings of silicone prosthesis through the biophysical characteristic of adherence and microscopical aspects of the inflammatory reaction and collagen formation. Methods: Thirty two Wistar rats were used. In the dorsum of each animal a silicone elastomer with a smooth superficies and another coated with texturized silicone (Mentor) was implanted. Another one, with the same smooth superficies and other coated with silicone foam (Lifesil), making up in each side, of the dorsum, the texturized and silicone foam group respectively. The animals were split into four groups to be evaluated at 7, 14, 30 and 60 days. On the evaluation dates the implant adherence was verified witch a tensiometer and the values in kgf were obtained. The material was sent to histological analysis with hematoxilin-eosin and picrosirius colorations, to evaluate the inflammatory reaction and collagen synthesis, respectively. The obtained data were submitted to statistical treatment. Results: There was more adherence of the tissue to the silicone foam (P<0,001). The inflammatory reaction was more intense in the same group, but without statistical significance. The number of giant cells and granulomas were more frequent in the silicone foam group. There was statistical significance at the 60 days for granulomas (P<0,028) and for all subgroups about number of giant cells (P< 0,012 to P<0,036). The thickness of the capsule in the silicone foam group was bigger, with statistical significance at seven days (P<0,028) and 60 days (P<0,012). The collagen deposition showed no difference in statistical analysis. Conclusion: The capsular reaction to the silicone foam showed stronger adherence, bigger thickness and had more number of granulomas and giant cells. No difference was observed in the intensity of inflammatory reaction in relation to type I and III collagen, when compared to the texturized cover. Key words: Breast Implantation. Silicones. Biocompatible Materials. Contracture. Rats. RESUMO Objetivo:Comparar a reação capsular de dois revestimentos de próteses de silicone através da característica biofísica de aderência e dos aspectos microscópicos de reação inflamatória e formação de colágeno. Métodos: Implantaram-se no dorso de 32 ratos duas membranas de silicone ambas possuindo uma superfície lisa e outra diferindo em sua estrutura. Estes revestimentos foram de espuma de silicone (LifeSil) ou silicone texturizado (Mentor). Os dois grupos foram divididos em quatro sub-grupos conforme o tempo de pós-operatório avaliado: 7, 14, 30 e 60 dias. Obteve-se material para análise biofísica de aderência, a qual foi realizada com tensiômetro para obtenção de valores em kgf. O estudo microscópico da reação inflamatória e síntese de colágeno foi realizado com colorações de hematoxilina-eosina e picrosirius. Os dados foram submetidos a testes para avaliação da significância estatística. Resultados: Houve maior aderência do revestimento de espuma de silicone ao tecido capsular, sendo este valor...

Histological evaluation of capsules formed by silicon implants coated with polyurethane foam and with a textured surface in rats

“…In accordance to Balderrama et al 10 that found thinner capsule in the textured group in the subgroups of 7 and 60 days compared to silicone foam group with statistical significance, all subgroups evaluated in this study (30, 50, 70 and 90 days) the capsule was thinner in the textured group with a significant difference, although the comparison has been made with polyurethane-coated implants.…”

“…Regarding the characteristics of the collagen fibers according to Minami et al 20 and Balderrama et al 10 that found a decline in the amount of type III collagen fibers with increased type I collagen fibers with significant differences, the same result was found in this study from 50 days on.…”

“…Corroborating with Balderrama et al 10 findings, it was confirmed with significant difference that the foreign body reaction was lower in textured group at the time of 60 days when compared to the foam silicone group. In this research lower foreign body reaction in textured group in all subgroups was also obtained, although the comparison was made with implants coated with polyurethane foam.…”

“…The rats were anesthetized by intramuscular injection consisting of a combination of 1% ketamine (40 mg/kg) and 2% xylazine (8 mg/kg) 10 . The effectiveness of the anesthesia was assessed by the lack of movement, corneal reflex and motor reaction after holding a clamp on the adipose cushion of one of the hind legs, and a good ventilatory pattern 3 .…”

Biofunctionalization of surfaces using polyelectrolyte multilayers

“…The chemical composition of the surface of the biomaterial indeed plays a role, but its physical structure and surface topography are more important to predict the degree of fibrosis [18]. For example, implants with a smooth and non-degradable surface create a thicker fibrous capsule than rough or textured implants [19], [20]. Modern implants use different chemical and topographical modifications to regulate cellular adhesion, differentiation and de novo tissue deposition (see review [21]).…”