Maternal microbiome regulation prevents early allergic airway diseases in mouse offspring

Background: Asthma is a serious global health problem, severely affecting the lives of sufferers and their families. An exceptionally hygienic home and reduced microbial exposure can aggravate the incidence of childhood asthma.

Methods: Specific-pathogen-free BALB/c mice were pre-treated with bacterial lysate (BL; 1 mg/kg) as a high microbial load maternal mouse model, and then, the offspring mice were established as an allergic airway disease (AAD) model. The expression levels of TLR2, TLR4, and HDAC9 in the mother's intestine and the offspring's lungs were detected. Relevant indicators of regulatory T cells (Tregs) were identified in the mother and offspring mice. The changes in the expression of Th1-, Th2-, Th9-, and Th17-related cytokines in the offspring mice were evaluated among different pre-treated groups.

Results: After augmenting the mothers' intestinal microbiota through oral BL gavage, the expression of TLR2 and TLR4 in the colon mucosa and colon lymphoid tissues was enhanced and that of HDAC9 in the colon mucosa was decreased, and the proportion of spleen Tregs was increased. The offspring showed similar changes in the AAD model compared with the offspring of the control-group mothers: TLR2 and TLR4 expression in the lungs and the proportion of spleen Tregs increased, HDAC9 expression in the lungs decreased, and AAD-induced airway pathologic characteristics were reversed; additionally, Th1/Th2 and Th9 imbalances were rectified.

Conclusions: This study presents a new framework for the prevention of childhood asthma, elucidating the mechanism of regulating the mother's intestinal microbiome to protect the offspring's early asthma via animal experiments.