The Effects of Sub-chronic Administration of the Ethanolic Extract of Chromolaena odorata Leaves on the Immune System and Spleen of Male Wistar Rats

Chromolaena odorata, a neglected weed with wide spectrum is a multipurpose plant that contains high concentration of anti-inflammatory, anti-diarrheal, anti-hypertensive agents that protects against tissue damage. This study was designed to evaluate the effect of ethanolic leaf extract of Chromolaena odorata on the immune system and spleen of Albino Wistar Rats. 41 adult male rats weighing between 110g -140g were used for this study. LD50 was carried out using 13 rats while 28 rats were used for the experiment proper. The rats used for the experiment proper were divided into four groups of 7 animals each. Group A served as control group and received animal feed and distilled water only, Group B received 1000mg/kg of the leaf extract and water, Group C received 3000mg/kg of the leaf extract and water, and Group D received 6000mg/kg of the leaf extract and water. The ethanolic leaf extract of Chromolaena odorata was administered 4-times per week for 13 weeks. The animals were killed using diethyl ether suffocation, blood samples were collected by ocular puncture for haematological analysis of RBC, WBC and differentials, Platelets, CD4 and CD8 cells count, the spleen and peyer’s patches harvested, weighed and  the spleen  immediately fixed in 10% formol saline for histological analysis. Data was considered significant at p<0.05. Result showed a significant increase (p<0.05) in body weight in the groups when compared to the control group A. Peyer’s patches had a significant decrease (p<0.05) in group B and C, while group D had a significant increase (p>0.05). Hemoglobin concentration, and PCV revealed a significant (p<0.05) decrease when compared to the control group. RBC result showed a significant (p<0.05) decrease when compared to group A. Platelet count revealed a significant (p<0.05) increase in the groups. CD4 and CD8 count also revealed a significant increase. Histopathological study showed reactive lymphoid follicles in group B, circumferential zone of necrosis around a disc shaped eosinophilic, foreign material was seen in group C, and group D had necrosis when compared to control group. In conclusion, the ethanolic leaf extract of Chromolaena  odorata have toxic effect on hematological indices of RBC, PCV with no effect on immune cell functions of Cd4 and CD8 cell counts and white blood cells.