Blood smears analysis: a valuable tool for profiling circulating erythrocytes and leukocytes in mouse model of leishmaniasis

Abstract

Although blood smear analysis can yield valuable insights into the health status of laboratory animals, it is not frequently performed in studies involving mouse models of leishmaniasis. Thus, to underscore its importance, we conducted microscopic evaluation of blood smears prepared from 10 µL of blood from L. (L.) amazonensis-infected BALB/c mice. Subsequently, we explored potential correlations between the identified hematological alterations, clinical evaluation data, and serum levels of total proteins (TP), albumin (Alb), globulins (Glob), IL-17A, and IL-10. Our findings revealed that infected mice exhibited an increased erythrocyte count, alongside a higher prevalence of microcytic and hypochromic erythrocytes. Moreover, it was observed elevated relative and absolute numbers of neutrophils and monocytes and reduced relative and absolute numbers of lymphocytes. A significant proportion of monocytes and lymphocytes in infected animals displayed reactive features. The relative number of lymphocytes was negatively correlated with the serum levels of Glob. Furthermore, the frequency of reactive lymphocytes was positively correlated with the serum levels of Glob and IL-17A. There was also a positive correlation between the absolute number of neutrophils and the serum levels of IL-17A and the frequency of reactive monocytes and the serum levels of Glob. Therefore, these findings, collectively, underscore the importance of blood smear analysis for elucidating both the quantitative and qualitative hematological changes experimentally induced by Leishmania infection. Integration of this technique into research protocols involving different mouse models of leishmaniasis holds immense potential for advancing our knowledge of this infectious disease and enhancing clinical management strategies.