Lactobacillus paracasei AH2 isolated from Chinese sourdough alleviated gluten-induced food allergy through modulating gut microbiota and promoting short-chain fatty acid accumulation in a BALB/c mouse model.

Abstract

A large number of people worldwide suffer from gluten-induced food allergy. As investigated in our previous research, Lactobacillus paracasei AH2 isolated from traditionally homemade sourdough in Anhui province of China showed the potential to reduce the immune reactivity of wheat protein by in vitro evaluation. However, whether L. paracasei AH2 has a role in alleviating wheat allergy in an in vivo model and its underlying mechanisms have not been elucidated. In this study, the alleviative effects of L. paracasei AH2 on gluten-induced allergic response were evaluated. Compared with a gluten-allergic mouse, L. paracasei AH2 suppressed anaphylaxis symptoms, gluten-specific immunoglobulin E, histamine and interleukin-4. Moreover, L. paracasei AH2 attenuated splenomegaly and induced Th1 or Treg cell differentiation to modulate the Th1/Th2 immune balance toward Th1 polarization. Short-chain fatty acid (SCFA) levels were enhanced after L. paracasei AH2 supplementation, contributing to allergy relief as well as reducing the pH of colonic contents. The α and β diversities of the gut microbiota were modulated by L. paracasei AH2 with increased relative abundance of Lacticaseibacillus and SCFA producers (Faecalibaculum, Alloprevotella and Bacteroides genera), as well as decreased unfavorable Lachnospiraceae_NK4A136_group and Alistipes. Additionally, L. paracasei AH2 protected the intestinal barrier function by upregulating tight junctions and improved the antioxidant activities in serum. Our findings indicate that L. paracasei AH2 could act as a potential probiotic for relieving wheat allergy by modulating the gut microbiota and elevating SCFA levels. © 2023 Society of Chemical Industry.