Lactobacilli facilitate maintenance of intestinal membrane integrity during Shigella dysenteriae 1 infection in rats.

OBJECTIVE Lactobacilli are used in various dairy products and fermented foods for their potential health beneficial effects. Recently we reported the protective role of Lactobacillus rhamnosus and Lactobacillus acidophilus during Shigella dysenteriae 1 infection. Nevertheless, investigations on the membrane-stabilizing effect of L. rhamnosus and L. acidophilus have not been done. Hence, the present study evaluated the effect of L. rhamnosus and L. acidophilus on the maintenance of intestinal membrane integrity during S. dysenteriae 1-induced diarrhea in rats. METHODS Rats were divided into eight groups (n = 6 in each group). Induced rats received single oral dose of S. dysenteriae (12 x 10(8) colony-forming units [cfu]/mL). Treated rats received L. rhamnosus (1 x 10(7)cfu/mL) or L. acidophilus (1 x 10(7)cfu/mL) orally for 4 d, alone or in combination, followed by Shigella administration. At the end of the experimental period, animals were sacrificed and the assay of membrane-bound adenosine triphosphatases (Na(+)/K(+)-ATPase, Ca(2+)-ATPase, and total ATPase), immunoblot analysis of tight junctional proteins (claudin-1 and occludin), and transmission electron microscopic studies were performed. RESULTS Induced rats showed a significant (P < 0.05) reduction in the membrane-bound ATPases and reduced expression of tight junction proteins in the membrane, coupled with their increased expression in the cytosol, indicating membrane damage. Transmission electron microscopic studies correlated with biochemical parameters. Pretreatment with combination of L. rhamnosus and L. acidophilus significantly prevented these changes. CONCLUSION Lactobacillus rhamnosus and L. acidophilus synergistically offered better protection to the intestinal membrane when compared with individual treatments with these strains during S. dysenteriae 1 infection.