Lactobacillus rhamnosus CNCM I-3690 and the commensal bacterium Faecalibacterium prausnitzii A2-165 exhibit similar protective effects to induced barrier hyper-permeability in mice

Impaired gut barrier function has been reported in a wide range of diseases and syndromes and in some functional gastrointestinal disorders. In addition, there is increasing evidence that suggests the gut microbiota tightly regulates gut barrier function and recent studies demonstrate that probiotic bacteria can enhance barrier integrity. Here, we aimed to investigate the effects of Lactobacillus rhamnosus CNCM I-3690 on intestinal barrier function. In vitro results using a Caco-2 monolayer cells stimulated with TNF-α confirmed the anti-inflammatory nature of the strain CNCM I-3690 and pointed out a putative role for the protection of the epithelial function. Next, we tested the protective effects of L. rhamnosus CNCM I-3690 in a mouse model of increased colonic permeability. Most importantly, we compared its performance to that of the well-known beneficial human commensal bacterium Faecalibacterium prauznitzii A2-165. Increased colonic permeability was normalized by both strains to a similar degree. Modulation of apical tight junction proteins expression was then analyzed to decipher the mechanism underlying this effect. We showed that CNCM I-3690 partially restored the function of the intestinal barrier and increased the levels of tight junction proteins Occludin and E-cadherin. The results indicate L. rhamnosus CNCM I-3690 is as effective as the commensal anti-inflammatory bacterium F. prausnitzii to treat functional barrier abnormalities.     

A model of localized osteolysis induced by the MBT-2 tumor in mice and its responsiveness to etidronate disodium

Summary A new experimental method to test the effect of drugs on tumor-induced osteolysis using a bladder tumor in mice has been designed. The method consistsed of inoculating MBT-2 tumor cells s.c. over the calvaria in mice, resulting in a local tumor causing fragmentation of the bone. This was accompanied by adjacent osteoplastic changes, which were evaluated by X-ray and histological examination. Etidronate disodium (EHDP), a diphosphonate derivative, at a dose of 3 mg/kg to 30 mg/kg s. c. protected the bone by decreasing the extent of osteolysis as judged by the same criteria. Therapy with EHDP prolonged the survival period. This inhibition was obtained with no apparent effect on the growth of the MBT-2 tumor.