Indigofera oblongifolia leaf extract regulates spleen macrophage response during Plasmodium chabaudi infection

Abstract

Malaria is a major health problem that still affects numerous countries. The current study aimed to identify the role of Indigofera oblongifolia leaf extract in regulating mouse spleen macrophages during the progression of Plasmodium chabaudi infection. Three doses of the leaf extract (100, 200, and 300 mg/kg) were administered to mice inoculated with P. chabaudi infected erythrocytes. The weight of the infected mice improved after the treatment with I. oblongifolia. The infection causes disorganization of macrophage distribution in the spleen. After the mice had been treated with the leaf extract, the macrophages appeared to be reorganized in the white and red pulp areas. In addition, the I. oblongifolia leaf extract (IOLE) significantly increased the total antioxidant capacity of the mice spleens infected with P. chabaudi. The phagocytic activity of spleen macrophages was increased in the infected group as indicated by the significant decrease in the number of fluorescent particles in the spleen sections. This number increased in the mice spleens after treatment with IOLE. Based on these results, it is suggested that IOLE regulate macrophage response of the spleen during the blood stage of malaria in mice.

Keywords: Fluorescent particles; Indigofera oblongifolia leaf extract; Mice; Phagocytosis; Spleen.

Fig. 1

I. oblongifolia-induced weight changes in mice due to infection with P. chabaudi on day 7 postinfection (p.i.). Values are means ± standard deviation (SD). ^a P < 0.05 and ^b P < 0.01 compared with non-infected and infected (-IOLE) group, respectively.

Fig. 2

Spleen sections labeled with macrophage detecting anti-cluster of differentiation 68 (CD68) antibody. CD68-positive cells appeared brown. (A) Uninfected spleen. (B) Infected spleen. Infected I. oblongifolia-treated (C) 100, (D) 200, and (E) 300 mg/kg spleens. Scale bar = 25 µm.

Fig. 3

I. oblongifolia-induced changes in number of cluster of differentiation 68 (CD68)-positive cells in the spleen of mouse infected with P. chabaudi on day 7 postinfection (p.i.). Results are total positive numbers from 10 random and continuous fields from each section. Values are means ± standard deviation (SD). ^a P < 0.01 and ^b P < 0.01 compared with non-infected and infected (-IOLE) groups, respectively.

Fig. 4

Changes in total antioxidant capacity of the spleens of mice infected with P. chabaudi and after treatment with I. oblongifolia leaf extracts. Values are means ± standard deviation (SD). ^a P < 0.01 and ^b P < 0.01 compared with non-infected and infected (-IOLE) groups, respectively.

Fig. 5

I. oblongifolia regulates spleen phagocytosis during P. chabaudi infection (A) Uninfected spleen with more fluorescent particles. (B) Infected spleen with reduced fluorescent particles. (C) Infected I. oblongifolia-treated (100 mg/kg) spleens with increased fluorescent particles. Scale bar = 100 µm.

Fig. 6

Semiquantitative evaluation of fluorescence intensity for 5 cryosections per mouse. Values are means ± standard deviation (SD). ^a P < 0.01 and ^b P < 0.01 compared with non-infected and infected (-IOLE) groups, respectively.