Caracterização microscópica de lesões causadas por leptospira spp. em útero bovino em modelo explante

Abstract

In Brazil, about 30% of the cows have reproductive problems that are largely related to infections caused by Leptospira spp, although researches investigating the pathogeny of this process are still limited. With this regard, the aim of this study was to investigate, by means of a histopathological analysis, the uterine tissue colonized by this agent. For this, Leptospira spp. sorovar Hardjo was inoculated in gravid and non-gravid uteri fragments of healthy cows. After incubation, the explants were processed and stained with hematoxylin and eosin, and the analysis of histology slides was performed by classifying them according to inflammation scores. From the total uteri tissue evaluated, 50% (5/10) did not show any evidence of inflammation, whereas the other half (5/10) exhibited a certain grade of inflammation. In group 1 (non-gravid uteri),50% (3/6) of the fragments did not present inflammatory alterations, 33.3% (2/6) presented score 1 and 16.6% (1/6) reached score 2. Alternatively, 50% (2/4) of the samples in group 2 (gravid uteri) did not show any elements that could represent an inflammatory process, and the remaining samples (2/4) were classified as score 1. Wilcoxon test showed no significant differences in the inflammation scores between gravid and non-gravid groups (p=0.906185616). It could not be discarded that even the mild alterations that occurred in part of the tissue analyzed could in fact interfere with the reproduction. It is hypothesized that the inflammatory response observed in this in vitro study was not as expressive as it could be in vivo. In conclusion, that with the microscopic investigation of cultured uterine explants, it was possible to verify mild to moderate inflammatory lesions evaluated according to the pre-established standard, but in vitro culture of bovine uteri fragments is still a new method that requires more investment to become a tool in the elucidation of the pathogenesis of the reproductive disease caused by Leptospira spp.