Comparative experimental investigation on the efficacy of mono- and multiprobiotic strains in non-alcoholic fatty liver disease prevention

Background: To investigate the efficacy of different probiotic strains, their combinations and forms (alive or lyophilized) in nonalcoholic fatty liver disease (NAFLD) prevention. Methods: In this study, 70 rats have been used divided into 7 groups of 10 animals in each: I -intact rats, II-VII rats with monosodium glutamate (MSG)-induced NAFLD. Rats with NAFLD were untreated (group II, MSG-obesity group) and treated with probiotics (groups III-VII). In order to develop NAFLD, newborn rats of groups II-VII were injected with a solution of monosodium glutamate (MSG) (4 mg/g) subcutaneously (s.c.) at 2nd, 4th, 6th, 8th, 10th postnatal day. The groups III-V received lyophilized monoprobiotics B. animalis VKL, B. animalis VKB, L. casei IMVB-7280, respectively. The group VI received 2.5 ml/kg of an aqueous solution of a mixture of the three probiotic strains (2: 1: 1 Lactobacillus casei IMVB-7280, Bifidobacterium animalis VKL, Bifidobacterium animalis VKB) at a dose of 50 mg/kg (5 x 10(9) CFU/kg) (g) (intragastrically). The group VII was treated with multiprobiotic Symbiter containing biomass of 14 alive probiotic strains (Lactobacillus + Lactococcus (6 x 10(10) CFU/g), Bifidobacterium (1 x 10(10)/g), Propionibacterium (3 x 10(10)/g), Acetobacter (1 x 10(6)/g)) at a dose of 140 mg/kg (1.4 x 10(10) CFU/kg). The treatment with probiotics was started at the age of 1 month. There were 3 courses of treatment, each included 2-week administration and 2-week break. All parameters were measured in 4-month aged rats. Results: Introduction of MSG during the neonatal period leads to the NAFLD development in the 4-months old rats. For steatosis degree there was no significant difference between MSG-obesity group and lyophilized monocomponent probiotics groups (III-V). The highest manifestation of steatosis was observed for B. animalis VKL group (2.0 +/- 0.25) as compared to B. animalis VKB (1.70 +/- 0.21) and L. casei IMVB-7280 (1.80 +/- 0.20). The steatosis score changes between all monoprobiotics groups (III-V) were insignificant. Administration from birth of both alive (VII) and lyophilized (VI) probiotic mixture lead to a significant decrease by 69.5 % (p < 0.001) and 43.5 % (p < 0.025) of steatosis score respectively as compared to the MSG-obesity group (2.3 +/- 0.21 %). For both alive and lyophilized probiotic mixtures, reduction of lobular inflammation was observed. These histological data were confirmed by the significant decrease of total lipids and triglycerides content in the liver approximately by 22-25 % in groups treated with probiotic mixtures (VI, VII) compared to the MSG-obesity group. Conclusion: We established failure of NAFLD prevention with lyophilized monoprobiotic strains and the efficacy of probiotic mixture with the preference of alive probiotic strains.