Impactos da associação de doxiciclina e gentamicina com praziquantel no tratamento da esquistossomose murina aguda e análise comparativa de microbiotas

Abstract

Introduction and objectives: Schistosomiasis occurs in acute and chronic forms, differing in pathogenesis and host immune response, with impacts of microbiota and drugs on disease outcome. This study evaluated the effects of praziquantel (PZQ) in combination with doxycycline (DOX) and gentamicin (GEN) in the treatment of BALB/c mice infected with Schistosoma mansoni in the acute phase of schistosomiasis, in addition to a metataxonomic analysis of feces and liver of uninfected and infected mice. Methods: Hepatic and intestinal granulomas were evaluated by histopathological analysis, quantification of parasite load in liver tissue (real-time PCR and egg count) and biochemical parameters: ALT, AST, alkaline phosphatase and albumin by enzymatic colorimetric methods. Metataxonomic analysis using 16S rRNA gene sequencing of feces and liver was performed in two experimental groups, uninfected and infected. Main findings: In the infected group treated with the PZQ+DOX combination, granulomas with a larger diameter and an extensive infiltration of inflammatory cells around S. mansoni eggs, characteristic of the necrotic-exudative type, were observed, in addition to a disorganization in the collagenization structure. In the mice in the infected group treated with PZQ+GEN, it was observed that the granulomas were of reduced dimensions, presenting a greater quantity of giant cells around the eggs and fibroblasts organized in concentric layers, although these changes did not differ statistically. There was a higher percentage of granulomas in the exudative-productive phase with the treatments, with the group treated with the PZQ+GEN combination presenting the highest percentage of these granulomas in relation to the group treated only with PZQ. All treatments caused a significant decrease in the number of eggs in the liver as well as a reduction in the genetic material of S. mansoni per mg of liver tissue analyzed by real-time PCR. The PZQ+DOX combination potentiated the inflammatory damage associated with hepatic granulomas, as also observed in higher ALT levels. In animals treated with PZQ+GEN there was a significant increase in AST levels. Regarding the composition of the intestinal microbiota, it was observed that the infection caused an increase in the relative abundance of Bacteroidia (phylum Bacteroidetes) while decreasing the abundance of Clostridia (phylum Firmicutes) with a statistically significant difference. Conclusion: The combination of PZQ with DOX and GEN was able to alter the modulation of the granulomatous process, with DOX aggravating the inflammation associated with the granulomatous process and GEN accelerating the resolution of schistosomiasis in an experimental murine model of acute infection by S. mansoni. In the sequencing analyses of the 16S rRNA gene, it was observed that, in the fecal microbiota, the infection caused, already in the acute phase, a statistically different increase in Bacteroidetes and a decrease in Firmicutes. In the liver of infected and uninfected BALB/c mice, there were subtle changes in the microbial composition, but the deviations observed in the microbial community between the liver samples in this study were not impactful enough to generate statistically significant variations, although they correspond to the acute phase of schistosomiasis.