Lactobacillus rhamnosus alleviates intestinal barrier dysfunction in part by increasing expression of zonula occludens-1 and myosin light-chain kinase in vivo

Protective effect of 4 lactobacilli on tumor necrosis factor-α (TNF-α)–induced changes in A) transepithelial resistance (TER) and B) IL-8 secretion by Caco-2 cells. Caco-2 cell monolayers were treated with each species (10⁵ cfu/well) or with medium alone (control) for 1h, and the monolayers were exposed to TNF-α. Results are expressed as means ± standard error (n=3). **P<0.01 versus controls (none); #P<0.05 and ##P<0.01 versus TNF-α alone (–). Ld = Lactobacillus delbrueckii ssp. bulgaricus no. 3; Lc = Lactobacillus casei no. 9; Lg = Lactobacillus gasseri no. 10; Lr = Lactobacillus rhamnosus OLL2838.

Protective effect of Lactobacillus rhamnosus OLL2838 (Lr) and OLL2838-conditioned medium (Lr-CM) on tumor necrosis factor-α (TNF-α)–induced change in A) transepithelial resistance (TER) and B) IL-8 secretion by Caco-2 cells. Caco-2 cell monolayers were treated with OLL2838 (10⁵ cfu/well), OLL2838-conditioned medium, or medium alone for 1h and exposed to TNF-α. Results are expressed as means ± standard error (n=3). **P<0.01 versus controls (none); ##P<0.01 versus TNF-α alone (–).

The effect of Lactobacillus rhamnosus OLL2838 on expression of A) zonula occludens-1 (ZO-1) and B) myosin light-chain kinase (MLCK) in Caco-2 cells. Caco-2 cell monolayers were treated with OLL2838 (10⁵ cfu/well) or medium alone for 1h and exposed to tumor necrosis factor-α (TNF-α). The expression of ZO-1, MLCK, and α-tubulin was detected by Western blotting of the cellular lysates. Images are representative of 3 independent experiments. Results are expressed as means ± standard error (n=3). *P<0.05 and **P<0.01 versus the controls (none); #P<0.05 versus TNF-α alone (–).

The effect of supplementation of live (Lr) or heat-killed (HK-Lr) Lactobacillus rhamnosus OLL2838 on dextran sodium sulfate (DSS)-induced colitis. A) Study design; B) body weight change; C) macroscopic view of the colons on d 5; and D) colon length on d 5. Results are expressed as means±standard error (n=4). *P<0.05 and **P<0.01 versus controls (none); #P<0.05 and ##P<0.01 versus DSS-treated mice (DSS).

Effect of supplementation of live (Lr) or heat-killed (HK-Lr) Lactobacillus rhamnosus OLL2838 on myeloperoxidase (MPO) activity in the proximal and distal colon of dextran sodium sulfate (DSS)-induced colitis mice. On d 5, the mice were killed and the MPO activity was measured. Results are expressed as means±standard error (n=4). *P<0.05 versus control mice (none); ##P<0.01 versus DSS-treated mice (DSS).

Protective effect of supplementation of live (Lr) or heat-killed (HK-Lr) Lactobacillus rhamnosus OLL2838 on increase in A) intestinal permeability and the expression of B) zonula occludens-1 (ZO-1) and C) myosin light-chain kinase (MLCK) on dextran sodium sulfate (DSS)-induced colitis mice. On d 5, mice (n=3) were gavaged with fluorescein isothiocyanate (FITC)-labeled dextran (60mg/100g of BW), and the serum level was measured 4h later (A). Separately, the proteins in the distal colons from each group (n=4) were extracted after the experiment shown in Figure 4 and used for SDS-PAGE and Western blotting. Images are representative of 3 independent experiments (B and C). Results are expressed as means±standard error. **P<0.01 versus control mice (none); ##P<0.01 versus DSS-treated mice (–).