Immunohistochemical study of renal fibropoiesis associated with dogs naturally and experimentally infected with two different strains of Leishmania (L.) infantum.

The objectives of this work were to study some pathological aspects of kidneys obtained from dogs naturally infected with Leishmania infantum and from dogs experimentally infected with two different strains of L infantum with special emphasis on fibrotic process. Seventy eight specimens of paraffin-embedded kidney fragments were collected as follows: (a) CNI group composed by 62 kidney samples of adult mongrel dogs, naturally infected with L infantum; (b) BH401 group composed by five kidney samples of adult Beagles experimentally infected with L infantum strain MCAN BR/2002/BH401; (c) BH400 group composed by eleven kidney samples of adult Beagles experimentally infected with L infantum strain MCAN/BR/2000/BH400, at the same dose and same route of the previous group, denominated group BH400; Control group (CC) composed by four kidney samples of adult Beagles. All animals revealed glomerular and interstitial fibropoiesis associated with different types of glomerulonephritis and chronic interstitial nephritis. Fibrosis was markedly more intense in the BH401 group, followed by animals in the CNI group. Markers for myofibroblasts (mesenchymal markers) such as alpha-actin (α-SMA), vimentin and the cytokine transforming growth factor beta (TGF-β) were done by immunohistochemistry. BH401 group showed higher expression of all these markers than others. Intracellular amastigotes forms of Leishmania was mainly found in BH401. These results could be indicating that the MCAN/BR/2002/BH401 strain is a good choice for the study of renal LVC experimental model.