O uso do sildenafil na viabilidade de retalhos cutâneos em ratas

Abstract

Introduction: Sildenafil citrate belongs to a relatively new class of drugs which mechanism of action occurs by the inhibition of phosphodiesterase-5 that is responsible for the degradation of intracellular cyclic guanosine monophosphate (cGMP). The cGMP promotes vasodilatation, alteration on platelet degranulaiton and angiogenesis. In this context, its vasoactive effects may increase the flaps blood flow, improving their viability. Purposes: 1- To evaluate the viability of the dorsal cutaneous flaps in female rats, using sildenafil, by the pathway subdermic or intraperitoneal. 2- To compare these pathways. Methods: Forty females rats Wistar were submitted to a confection of cranially based dorsal cutaneous flaps and arranged into four groups: Subdermic study group (application of sildenafil subdermic), Subdermic control group (application of saline solution 0,09% subdermic), Intraperitoneal study group (application of sildenafil intraperitoneal), Intraperitoneal control group (application of saline solution 0,09% intraperitoneal). Seven days after the surgery, the flaps were photographed and graphically represented, in order to be analyzed with AutoCad software. Three samples of each flap were collected for histological analyses. Results: By the macroscopic analyses, the animals belonging to the group Subdermic study group presented larger areas of necrosis (p=0,003) of the dorsal flaps. Also, the histological analyses of the distal third of these flaps showed poor formation of granulation tissue. By the macroscopic analyses, its use intraperitoneal was associated to a better tissue contraction (p=0,019), although there was less presence of granulation tissue with polymorphonuclears into the distal third of the flaps (p=0,001) and more necrosis interposing the areas of granulation into the middle third of the flaps (p=0,001), in the Intraperitoneal study group. Conclusion: The sildenafil citrate, applied by the two routes of administration, was related to a poor viability of the dorsal cutaneous flaps of female rats. Comparing the two pathways of administration, the sildenafil subdermic was associated to poor flap viability and worse tissue contraction.