Mesenteric injection of adipose-derived mesenchymal stem cells relieves experimentally-induced colitis in rats by regulating Th17/Treg cell balance.

Efficient delivery routes are critical for the effectiveness of adipose-derived mesenchymal stem cells (ADMSCs) in treating inflammatory bowel disease (IBD). Conventional ADMSC delivery routes include local, intravenous and intraperitoneal injection. Whether mesenteric injection has potential in IBD treatment remains unknown. In the present study, we investigated the therapeutic effects of mesenteric injection of ADMSCs in a trinitrobenzene sulfonic acid-induced rat IBD model and explored whether this treatment affected T helper 17 (Th17)/regulatory T (Treg) cell ratio. The results showed that mesenteric injection of ADMSCs markedly reduced signs of colitis, colon shortening, weight loss and pathological damage. The treatment also decreased serum tumor necrosis factor alpha concentration, increased serum tumor necrosis factor alpha-stimulated gene protein 6 concentration, and augmented repair via proliferation (assessed by evaluating Ki-67 levels) in colonic tissue. Moreover, mesenteric injection of ADMSCs reduced interleukin (IL)-17A and IL-6 mRNA expression, and increased IL-10 and transforming growth factor-beta mRNA expression in colonic tissue. Protein analyses indicated that mesenteric injection of ADMSCs was associated with increased expression of forkhead box P3+ and IL-10 as well as decreased expression of retinoid-related orphan receptor λt and IL-17. Additionally, the treatment inhibited phosphorylation of signal transducer and activator of transcription (STAT) 3 and activated phosphorylation of STAT5. Taken together, these results suggest that mesenteric injection of ADMSCs is a promising approach to treating trinitrobenzene sulfonic acid-induced IBD, and achieves its therapeutic effect by regulating the pro/anti-inflammatory Th17/Treg cell balance.