Lafutidine, a histamine H2 receptor antagonist with mucosal protective properties, attenuates 5-fluorouracil-induced intestinal mucositis in mice through activation of extrinsic primary afferent neurons.

Intestinal mucositis accompanied by severe diarrhea is one of the most common side effects during cancer chemotherapy. Lafutidine, a histamine H2 receptor antagonist with mucosal protective properties via sensory afferent neurons, is used for the treatment of upper gastrointestinal diseases. The present study investigated the effects of lafutidine on 5-fluorouracil (5-FU)-induced intestinal mucositis induced in mice. Male C57BL/6 wild-type (WT), sensory deafferented mice, and transient receptor potential vanilloid subfamily 1 knockout (TRPV1KO) mice were used. Animals were administered 5-FU once daily, while lafutidine and famotidine were administered twice daily for 6 days. Repeated administration of 5-FU caused severe intestinal mucositis, characterized by shortening of villi and destruction of crypts and was accompanied by diarrhea and body weight loss. Daily administration of lafutidine reduced the severity of intestinal mucositis, diarrhea and body weight loss in a dose-dependent manner, while famotidine had no effect on intestinal mucositis. The preventive effects of lafutidine were completely abolished in sensory deafferented and TRPV1-KO mice. Lafutidine significantly suppressed 5-FU-increased MPO activity and inflammatory cytokine expression on day 6, but not apoptosis induction in intestinal crypts on day 1. Lafutidine induced Alcian Blue and PAS-positive mucus production in the small intestine. These findings suggest that lafutidine attenuates 5-FU-induced intestinal mucositis, most likely by increasing mucus production via activation of sensory afferent neurons. Furthermore, intact TRPV1 signaling is essential for the activation of sensory afferent neurons induced by lafutidine. Therefore, lafutidine is more useful than other common antacids for the treatment of intestinal mucositis during cancer chemotherapy.