Alterações do colágeno e do sistema elástico induzidas pela hiperatividade do detrusor em coelhos: ação da oxibutinina

Abstract

O presente estudo tem como objetivo avaliar as alterações histopatológicas e histomorfométricas do colágeno e das fibras do sistema elástico na bexiga, utilizando um modelo experimental de hiperatividade do detrusor (HD) em coelhos com obstrução parcial da bexiga (OPB) submetidos à oxibutinina intravesical. Materiais e Métodos: Quarenta e cinco coelhos machos Norh Folk, pesando em média 2207,4 g, foram divididos, de forma randomizada, em 3 grupos. Grupo I (GI): controle clínico (n=15), sem intervenção cirúrgica; os outros animais foram submetidos à OPB, no momento M0, utilizando uma técnica previamente descrita por Balasthegin. Desses animais, 29 desenvolveram HD, avaliada por estudo cistométrico uma semana após a cirurgia, no momento M1, e foram divididos, de forma randomizada, em grupo GII (n=14) e grupo GIII - OPB + oxibutinina intravesical (n=15, 0.5 mg/kg peso corporal, diariamente por 28 dias). Um animal foi excluído por não ter desenvolvido HD. Creatinina sérica, cultura de urina e estudo cistométrico foram realizados em todos os animais, uma semana após OPB (M1) e 4 semanas após M1 (M2), quando os animais foram sacrificados. O diâmetro das fibras musculares foram medidas nas secções de bexigas coradas com HE e determinadas em μm. As secções foram também coradas pela técnica de Picro-Sirius Red para evidenciar colágeno e pela Fuccina Resorcina de Weighert para caracterizar as fibras do sistema elástico. As análises...

The present study aims to evaluate the histopathological and histomorphometric changes of collagen and fibers of the elastic system in the bladder, using an experimental model of detrusor hyperactivity (DH) in rabbits with partial bladder outlet obstruction (PBOO) that underwent intravesical oxybutynin. Material and Methods: Forty-five North Folk male rabbits, weighting on average 2,207.4 g, were randomly divided into 3 groups. Group GI: controls (n=15), in which there was no surgical intervention; the remaining animals were submitted to PBOO, at M0 moment, as previously described by Balasteghin. 29 of the animals developed DH, verified by a cystometric study conducted one week after surgery, at M1 moment, and were randomly divided into group GII (n=14) and group GIII - PBOO + intravesical oxybutynin (n=15, 0.5 mg/kg body weight, daily for 28 days). One animal was excluded because it did not develop DH. Serum creatinine, urine culture, and cystometric study were performed on all animals one week after PBOO (M1) and 5 weeks after PBOO (M2), when the animals were sacrificed. Diameter of muscle fiber was measured on HE-stained bladder sections and is given in μm. Sections were also stained by Picro-Sirius Red technique for evidencing collagen and by Weigert’s Fuchsin- Resorcin for characterizing the elastic system fibers. The morphometric analyses were carried out using the program Pro- Image Plus and Image J. The biochemical collagen concentration in the bladder wall was determined by a hydroxyproline assay and was expressed as μg hydroxyproline per mg dry, defatted tissue. Results: After 4 weeks, bladder weight was significantly higher in animals from GII and GIII as compared to GI (9.61 ± 5.36 and 6.00 ± 2.18 vs 2.35 ± 0.55, respectively)...(Complete abstract click electronic access below)