Superoxide overproduction and kidney fibrosis: a new animal model.

OBJECTIVE: To establish whether the mutation in the Immp2L gene induces renal fibrosis and whether aging exacerbates renal morphology in mice. METHODS: Female mutant mice with mutation in the inner mitochondrial membrane peptidase 2-like protein at 3 and 18 months of age were used. Renal fibrosis was analyzed using classic fibrosis score, Masson's trichrome staining, and analysis of profibrotic markers using real time polymerase chain reaction (superoxide dismutase 1, metalloproteinase-9, erythropoietin, transforming growth factor beta), and immunostaining (fibroblasts and Type IV collagen). Oxidative stress markers were determined by immunohistochemistry. The number of renal apoptotic cells was determined. Renal function was estimated by serum creatinine. RESULTS: Young mutant mice had significantly more glomerulosclerosis than age-matched mice (p=0.034). Mutant mice had more tubular casts (p=0.025), collagen deposition (p=0.019), and collagen type IV expression (p<0.001). Superoxide dismutase 1 expression was significantly higher in young mutants (p=0.038). Old mutants exhibited significantly higher expression of the fibroblast marker and macrophage marker (p=0.007 and p=0.012, respectively). The real time polymerase chain reaction of metalloproteinase-9 and erythropoietin were enhanced 2.5- and 6-fold, respectively, in old mutants. Serum creatinine was significantly higher in old mutants (p<0.001). CONCLUSION: This mutation altered renal architecture by increasing the deposition of extracellular matrix, oxidative stress, and inflammation, suggesting a protective role of Immp2L against renal fibrosis.

Superoxide overproduction and kidney fibrosis: a new animal model / Produção aumentada de superóxido e fibrose renal: novo modelo animal

Objective To establish whether the mutation in the Immp2L gene induces renal fibrosis and whether aging exacerbates renal morphology in mice. Methods Female mutant mice with mutation in the inner mitochondrial membrane peptidase 2-like protein at 3 and 18 months of age were used. Renal fibrosis was analyzed using classic fibrosis score, Masson’s trichrome staining, and analysis of profibrotic markers using real time polymerase chain reaction (superoxide dismutase 1, metalloproteinase-9, erythropoietin, transforming growth factor beta), and immunostaining (fibroblasts and Type IV collagen). Oxidative stress markers were determined by immunohistochemistry. The number of renal apoptotic cells was determined. Renal function was estimated by serum creatinine. Results Young mutant mice had significantly more glomerulosclerosis than age-matched mice (p=0.034). Mutant mice had more tubular casts (p=0.025), collagen deposition (p=0.019), and collagen type IV expression (p<0.001). Superoxide dismutase 1 expression was significantly higher in young mutants (p=0.038). Old mutants exhibited significantly higher expression of the fibroblast marker and macrophage marker (p=0.007 and p=0.012, respectively). The real time polymerase chain reaction of metalloproteinase-9 and erythropoietin were enhanced 2.5- and 6-fold, respectively, in old mutants. Serum creatinine was significantly higher in old mutants (p<0.001). Conclusion This mutation altered renal architecture by increasing the deposition of extracellular matrix, oxidative stress, and inflammation, suggesting a protective role of Immp2L against renal fibrosis. .

Objetivo Estabelecer se a mutação no gene Immp2L induz à fibrose renal e se o envelhecimento exacerba a morfologia renal em camundongos. Métodos Foram usadas fêmeas de camundongos mutantes para proteína semelhante à peptidase 2 da camada interna da mitocôndria, com 3 e 18 meses de idade. Para analisar a fibrose renal, foram usados o escore clássico de fibrose, a coloração com tricrômio de Masson, e a análise de marcadores profibróticos, por meio da reação em cadeia de polimerase em tempo real (superóxido dismutase 1, metalonoproteinase-9, eritropoietina e fator transformador de crescimento beta), e a imunocoloração (fibroblastos e colágeno IV). Marcadores de estresse oxidativo foram determinados por imuno-histoquímica. O número de células apoptóticas renais foi analisado. A função renal foi estimada por creatinina sérica. Resultados Camundongos mutantes jovens apresentaram glomeruloesclerose em quantidade significativamente maior que animais da mesma idade (p=0,034). Os mutantes mostraram maior formação de cilindros tubulares (p=0,025), deposição de colágeno (p=0,019) e maior expressão de colágeno do tipo IV (p<0,001). A expressão de superóxido dismutase 1 foi maior em mutantes jovens (p=0,038). Mutantes idosas exibiram maior expressão dos marcadores de fibroblastos e macrófagos (p=0,007 e p=0,012, respectivamente). As reações da cadeia de polimerase em tempo real da metalanoproteinase-9 e da eritropoietina estavam aumentadas em 2,5 e 6 vezes, respectivamente, em mutantes idosas. A creatinina sérica foi significantemente maior em animais idosos mutantes (p<0,001). Conclusão Essa mutação alterou a arquitetura renal pelo aumento da deposição de matriz extracelular, estresse oxidativo e inflamação, sugerindo papel de proteção de Immp2L contra a fibrose renal. .