McKernan et al. [37] also observed significant increases in the TLR3, TLR4, and TLR5 mRNA levels in both the distal and proximal colonic mucosa of MS rats compared with controls, which suggests that innate immune receptor expression may be changed in the gastrointestinal tract of animals with stress-induced IBS-like symptoms. Here, TLR5 is linked to irritable bowel syndrome.