Dietary amaranths modulate the immune response via balancing Th1/Th2 and Th17/Treg response in collagen-induced arthritis

Imbalance between Th1/Th2 and Th17/Treg is crucial in RA progression. Various dietary factors can modulate the disease severity by restoring the balance in differentiation of CD4+ T cell subsets. Dietary amaranths hold an important part of diet as vegetables, where commonly consumed species includes Amaranthus cruentus (Ac), Amaranthus viridis (Av), and Amaranthus hybridus (Ah). The present study focuses on to evaluate whether these dietary amaranths can modulate the immune activation in collagen-induced arthritis. For in vivo study, Female Wistar rats were immunized with type II collagen and after immunization period, rats were separately supplemented with cooked Ac, Av, and Ah at 500 mg/100 g bwt concentration mixed with standard rat feed for 60 days. HPTLC fingerprint analysis identified peaks for compounds in these three amaranths. The results showed a protective role of immunomodulation in Th1/Th2 response of the three dietary amaranths, by significantly augmenting lymphocyte activation with increased IL-4 secretion, but decreased IFN-γ by cultured spleen lymphocytes subjected to collagen-induced inflammation. Moreover, Th17/Treg imbalance created by increase in IL-17 and decrease in IL-10 was significantly balanced by the three dietary supplemented groups. Furthermore, Th1/Th2 status reflected from Tbet/GATA3 ratio and Th17/Treg status reflected from RORγt/FOXP3 ratio was significantly decreased in the three dietary amaranth supplemented groups. Thus, dietary amaranths provide an immune-modulating role by keeping the balance between Th1/Th2 and Th17/Treg response in collagen-induced inflammation.

Keywords: Collagen-induced arthritis; Dietary amaranths; Immunomodulation; Th1/Th2; Th17/Treg.