Experimental study of the aloe polysaccharides relieving enteritis by regulating Th17/Treg cell balance

Abstract

Objective To investigate whether aloe polysaccharide from aloe extract can alleviate the enteritis induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS) via correcting Th17/Treg cell imbalance. Methods Thirty SD rats were divided into normal group (enema with phosphate buffered saline), aloe polysaccharide treatment group (enema with TNBS and ethanol and anal injection of aloe polysaccharide) andmodel group (enema with TNBS and ethanol) by complete digital random method, with 10 rats in each group. The bodyweight change and disease activity index (DAI) were recorded. The macroscopic and microscopic damage scoring of colon tissue were examined histopathologically. The myeloperoxidase (MPO) activity, mRNA expression level of cytokine transforming growth factor (TGF-β), interleukin (IL)-10, IL-17A and IL-6, as well as the protein expression of transcription factors Foxp3+, RORγt and the signal transducer and activator of transcription (STAT)3, STAT5 were detected in the colon tissue. The expression of IL-1β, tumor necrosis factor alpha (TNF-α) and anti-tumor necrosis factor alpha stimulating gene 6 (TSG-6) in the plasma were detected. Results Compared with the model group, DAI, MPO activity, histopathological scores and the protein expression of the plasma cytokines IL-1βand TNF-αin the aloe polysaccharide treatment group were significantly decreased, but the concentration of TSG-6 in the plasma was increased. Aloe polysaccharide inhibited the mRNA expression of pro-inflammatory cytokines IL-17A and IL-6 as well as transcription factor RORγt activation and STAT3 phosphorylation in colon tissue, but promoted the mRNA expression of anti-inflammatory cytokines IL-10, TGF-βas well as transcription factor Foxp3+activation and STAT5 phosphorylation. Conclusion Aloe polysaccharide can alleviate TNBS-induced experimental enteritis by correcting Th17/Treg cell imbalance. Key words: Inflammatory bowel disease; Aloe; Polysaccharides; Th17 cells; T-lymphocytes, regulatory