Lactitol Alleviates Loperamide-Induced Constipation in Sprague Dawley Rats by Regulating Serotonin, Short-Chain Fatty Acids, and Gut Microbiota

The objective of this study was to examine the impact of lactitol on constipation caused by loperamide in Sprague Dawley rats, with a particular emphasis on its underlying mechanisms and potential health advantages. The lactitol effectively improved fecal parameters, intestinal tissue structure, and the expression of constipation-related gene expression and proteins. Lactitol alleviated fecal weight and water content altered by loperamide and enhanced gastrointestinal transit. The administration also restored mucosal and muscular layer thickness. Mechanistically, lactitol upregulated the mRNA expression and/or protein levels of mucins (MUC2 and MUC4), occludin, claudin-1, and zonula occludens, indicating improved intestinal barrier function. Lactitol positively regulated the composition of cecal microbiota, leading to an increased relative abundance of Bifidobacterium, Lactobacillus, and Romboutsia. Conversely, lactitol decreased the relative abundance of Prevotella, Aerococcus, Muribaculum, Blautia, and Ruminococcus. This study demonstrated the potential of lactitol to relieve constipation by modulating the gut microbiota. These findings suggest that lactitol is an alternative to traditional laxatives and has potential as a health-promoting food sweetener.