Lactobacillus plantarum CQPC02-Fermented Soybean Milk Improves Loperamide-Induced Constipation in Mice

This study determined the ameliorative effects of the novel microorganism, Lactobacillus plantarum CQPC02 (LP-CQPC02), fermented in soybean milk, on loperamide-induced constipation in Kunming mice. High-performance liquid chromatography revealed that LP-CQPC02-fermented soybean milk (LP-CQPC02-FSM) had six types of soybean isoflavones, whereas Lactobacillus bulgaricus-fermented soybean milk (LB-FSM) and unfermented soybean milk (U-FSM) only had five types of soybean isoflavones. LP-CQPC02-FSM also contained more total and active soybean isoflavones than LB-FSM and U-FSM. Results from mouse experiments showed that the defecation factors (quantity, fecal weight and water content, gastrointestinal transit ability, and time to first black stool) in the LP-CQPC02-FSM-treated mice were better than those in the LB-FSM- and U-FSM-treated mice. The serum and small intestinal tissue experiments showed that soybean milk increased the motilin, gastrin, endothelin, acetylcholinesterase, substance P, vasoactive intestinal peptide, and glutathione levels and decreased the somatostatin, myeloperoxidase, nitric oxide, and malondialdehyde levels compared with the constipated mice in the control group. The LP-CQPC02-FSM also showed better effects than those of LB-FSM and U-FSM. Further results showed that LP-CQPC02-FSM upregulated cuprozinc-superoxide dismutase (Cu/Zn-SOD), manganese superoxide dismutase (Mn-SOD), catalase (CAT), c-Kit, stem cell factor (SCF), glial cell-derived neurotrophic factor (GDNF), neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), and aquaporin-9 (AQP9) and downregulated the expression levels of transient receptor potential cation channel subfamily V member 1 (TRPV1), inducible nitric oxide synthase (iNOS), and aquaporin-3 (AQP3) in the constipated mice. LP-CQPC02-FSM increased the Bacteroides and Akkermansia abundances and decreased the Firmicutes abundance in the feces of the constipated mice and decreased the Firmicutes/Bacteroides ratio. This study confirmed that LP-CQPC02-FSM partially reversed constipation in mice.