Effects of probiotics on loperamide-induced constipation in rats

Constipation, a common health problem, causes discomfort and affects quality of life. This study aimed to evaluate the potential effect of probiotics on loperamide (LP)-induced constipation in Sprague-Dawley (SD) rats, a well-established animal model of spastic constipation. In total, 100 male SD rats (age, 8 weeks; Japan SLC, Inc., Hamamatsu, Japan) were used in the experiments following a 12-day acclimatisation period. They were randomly divided into two treatment groups (groups 1 and 2) of 50 rats each. Spastic constipation was induced via oral administration of LP (3 mg/kg) for 6 days 1 hour before the administration of each test compound. Similarly, a probiotics solution (4 ml/kg body weight) was orally administered to the rats once a day for 6 days in group 2. In group 1, phosphate buffer solution was orally administered once a day for 6 days 1 hour after each LP administration. The changes in body weight, faecal parameters, short-chain fatty acid concentration in faeces, and faecal immunoglobulin (Ig)-A concentration were recorded. In the present study, the oral administration of probiotics improved faecal parameters, short-chain fatty acid concentration in faeces, and faecal IgA concentration. Our results indicate that probiotics increase the levels of intestinal short-chain fatty acids, especially butyric acid, thereby improving constipation and intestinal immunity.