Comparative histochemical studies of rats infected with a pathogenic and nonpathogenic trypanosome

Histochemical variations in tissues from rats inoculated with Trypanosoma lewisi and Trypanosoma rhodesiense were investigated. During peak parasitemia, the liver of rats inoculated with T lewisi showed increased glycogen distribution. However, glycogen depletion was noted in the liver and spleen of animals inoculated with living cells of T rhodesiense. Depletion was very apparent from day 4 to day 10. Throughout the period of observation, only a small amount of lipid infiltration occurred in tissues from animals inoculated with both organisms. Protein tests revealed a normal distribution of protein in tissues. Sections of the liver from rats inoculated with T lewisi showed strong alkaline phosphatase activity on days 7, 10, and 13. Alkaline phosphatase activity for T rhodesiense-infected animals was positive for days 4, 7, and 10. Strong positive reactions for acid phosphatase were observed on days 10 and 13 for some tissues (liver, spleen, and kidney) from rats inoculated with T lewisi. On days 4, 7, and 10, intense staining reactions also were observed for livers and spleens of animals inoculated with T rhodesiense. Regardless of tissues observed, histochemical variations were not observed in animals inoculated with the derivatives (ie, metabolic products and homogenates) of T lewisi and T rhodesiense.