Alginate/Arabic gum-chitosan-encapsulated Bacillus subtilis enhances probiotic viability and alleviates liver injury and fibrosis in cholestatic rats

Abstract

This study investigates the effects of encapsulated Bacillus subtilis (B. subtilis) on liver injury and fibrosis in a cholestatic rat model. Probiotics like B. subtilis have shown anti-inflammatory and antioxidant properties, but their efficacy is reduced by the harsh gastrointestinal tract (GIT) environment. Some studies have shown that encapsulation using a combination of alginate, Arabic gum, and chitosan can improve probiotic viability and promote controlled release in the intestine. In this study, male Wistar rats were randomly assigned to five groups: healthy control, cholestasis control, probiotic, free capsule, and encapsulated probiotic, to evaluate the protective effects of the encapsulated probiotic against cholestasis-induced damage. Encapsulated B. subtilis with the dosage of 3 × 10⁹ CFU/day was administered 1 week before and 3 weeks after cholestasis induction. After treating rats with free or encapsulated B. subtilis, or with free microcapsules for 4 weeks, liver function tests, gene expression (pro- and anti-inflammatory cytokines), antioxidant status, and liver histology were analyzed. The results demonstrated that encapsulation enhanced the viability of the probiotic in the simulated gastrointestinal environment. Rats receiving encapsulated B. subtilis exhibited improved liver function, reduced pro-inflammatory cytokines (IL-6, TNF-α), and lower α-SMA gene expression (fibrosis marker), alongside increased anti-inflammatory IL-10. Additionally, antioxidant status was improved, and liver histology showed protective effects. These findings suggest that encapsulated B. subtilis can mitigate cholestasis-induced liver injury, enhance liver function, and prevent fibrosis progression.

Keywords: Bacillus subtilis; Cholestasis; Encapsulation; Inflammation; Liver fibrosis; Oxidative stress; Probiotic.