Abstract
This study aimed to evaluate the comparative protective effects of lactic acid bacteria (LAB) strains against ethanol/HCl-induced gastric injury in rats and to identify strains with gastroprotective potential. Rats were orally administered three LAB strains for 14 days prior to the induction of gastric injury using 0.15 M HCl in 60% ethanol. Gastric tissues were collected for histopathological and molecular analyses. Pretreatment with the LAB strains significantly reduced the extent of mucosal damage compared with the EtOH/HCl-treated group. At the transcriptional level, ethanol/HCl exposure markedly decreased the expression of the mucus-associated gene Muc5ac and the anti-inflammatory gene Il10, while increasing the expression of pro-inflammatory genes including Tnf, Il6, and Ptgs2. In contrast, LAB administration restored Muc5ac and Il10 expression and suppressed the expression of pro-inflammatory genes. These findings were consistent with histological observations showing comparatively preserved gastric tissue architecture and less prominent inflammatory cell infiltration in LAB-treated groups. Notably, differences in protective efficacy were observed among the LAB strains, indicating strain-specific functional properties. These findings suggest that selected LAB strains are promising probiotic candidates for maintaining gastric health by preserving gastric mucosal integrity and regulating inflammatory responses.