Bifidobacterium animalis subsp. lactis BLa80 alleviates constipation in mice through modulating the stem cell factor (SCF)/c-Kit pathway and the gut microbiota

Probiotics, as health ingredients, have attracted widespread attention. However, due to the wide variety of probiotic species, their laxative effects and the underlying mechanisms remain elusive. In this study, we investigated the laxative effect of Bifidobacterium animalis subsp. lactis BLa80 (at concentrations of 1.0 × 10⁸, 2.0 × 10⁸, and 4.0 × 10⁸ CFU per mL, with a dosage of 0.2 mL each) in mice, utilizing a functional constipation mouse model induced with loperamide hydrochloride (0.2 mL, 10 mg per kg BW) for 7 consecutive days. Meanwhile, a blank group (treated with 0.2 mL of 0.9% saline) and a positive control group (treated with mosapride at a dose of 5 mg per kg BW) were also set up. The body weight, fecal water content, intestinal propulsion rate, colon tissue histology, fecal microbial composition, serum indices, and colon mRNA levels of the mice were measured, employing histological and biochemical assays, GC-MS, RT-qPCR and 16S rRNA gene sequencing etc. Results showed BLa80 could accelerate intestinal peristalsis, maintain fecal moisture, prevent intestinal barrier disruption, increase short-chain fatty acid production, prevent gut microbe dysbiosis and constipation in mice. It also helped to keep the levels of 5-hydroxytryptamine (5-HT), motilin (MTL), and substance P (SP) normal, up-regulated the mRNAs of intestinal mucin 2 (MUC2), stem cell factor (SCF), and the tyrosine kinase receptor c-Kit, and down-regulated the mRNA of aquaporins (AQPs), especially at a high-dose. This study indicated that BLa80 held the potential to emerge as a novel ingredient in functional foods designed for constipation relief and as a treatment alternative.