Cytokines, chemokines, insulin and haematological indices in type 2 diabetic male Sprague Dawley rats infected with Trichinella zimbabwensis

Abstract

Diabetes mellitus is a chronic metabolic disease induced by the inability to control high blood glucose level. Helminth-induced immunomodulation has been reported to prevent or delay the onset of type 2 diabetes mellitus (T2DM), which, in turn, ameliorates insulin sensitivity. Therefore, there is a need to understand the underlying mechanisms utilized by helminths in metabolism and the induction of immuno-inflammatory responses during helminthic infection and T2DM comorbidity. This study aimed at using a laboratory animal model to determine the cytokines, chemokines and haematological indices in diabetic (T2DM) male Sprague Dawley (SD) rats infected with Trichinella zimbabwensis. One hundred and two male SD rats (160–180 g) were randomly selected into three experimental groups (i. T2DM-induced group (D) ii. T. zimbabwensis infected + T2DM group (TzD) and iii. T. zimbabwensis-infected group (Tz)). Rats selected for the D group and TzD group were injected with 40 mg/kg live weight of streptozotocin (STZ) intraperitoneally to induce T2DM, while animals in the Tz and TzD group were infected with T. zimbabwensis. Results showed that adult T. zimbabwensis worm loads and mean T. zimbabwensis larvae per gram (lpg) of rat muscle were significantly higher (p < 0.001) in the Tz group when compared to the TzD group. Blood glucose levels in the D group were significantly higher (p < 0.001) compared to the TzD group. An increase in insulin concentration was observed among the TzD group when compared to the D group. Liver and muscle glycogen decreased in the D when compared to the TzD group. A significant increase (p < 0.05) in red blood cells (RBCs) was observed in the D group when compared to the TzD and Tz groups. An increase in haematocrit, haemoglobin, white blood cells (WBCs), platelet, neutrophils and monocyte were observed in the D group when compared to the TzD group. TNF-α, IFN-γ, IL-4, IL-10 and IL-13 concentrations were elevated in the TzD group when compared to the D and Tz groups, while IL-6 concentration showed a significant reduction in the Tz when compared to the D and the TzD groups. A significant increase in CCL5 in the D and TzD groups was observed in comparison to the Tz group. CXCL10 and CCL11 concentration also showed an increase in the TzD group in comparison to the Tz and the D groups. Overall, our results confirm that T. zimbabwensis, a parasite which produces tissue-dwelling larvae in the host, regulates T2DM driven inflammation to mediate a positive protective effect against T2DM outcomes.