Assessment of the Safety of Lactobacillus casei IMV B-7280 Probiotic Strain on a Mouse Model

Abstract

Probiotics, in particular Lactobacillus (lactic acid bacteria, LAB) strains, are widely used in clinical practice. Despite that these probiotics have GRAS (generally regarded as safe) and qualified presumption of safety (QPS) statuses, the safety of particular strains still needs to be thoroughly studied. The aim of the study was to evaluate the safety of Lact. casei IMV B-7280 strain by investigating toxicity and the effects on gut microbiota in experimental animal model. Male BALB/c mice (7–8 weeks, weight 20–24 g) were treated with amounts of Lact. casei IMV B-7280 strain: 5 × 10 6 , 5 × 10 8 , or 5 × 10 9 CFU/animal once per day during 7 days, or in the amount of 1 × 10 10 CFU/animal once per day during 3 days (most of the proposed probiotic doses for humans—from 10 8 to 10 9 CFU) and monitored during 14 days. Blood tests and serum biochemistry were conducted; the cecal content from mice of the experimental and control groups were freshly collected and analyzed. At the end of the experiments (15th day), the presence of LAB in the heart, liver, kidney, and mesenteric lymph nodes and peripheral blood was determined; histology of the brain, liver, heart, fragments of the small and large intestine, and mesenteric lymph nodes was conducted. Survival rate of BALB/c mice treated with Lact. casei IMV B-7280 strain in different concentrations in toxicity experiments during 14 days was 100%. We observed no signs of toxicity as changes in gait, lethargy, sleep, somatomotor activity as well as changes in fur, eyes, skin and mucous membranes, tremors, behavior pattern, convulsions, salivation, diarrhea, and local injuries in mice from all experimental groups. After administration of probiotic strain, the number of opportunistic bacteria in cecal contents, such as Staphylococcus spp., Candida spp., Pseudomonas spp., and total aerobic and optionally anaerobic bacteria decreased compared to controls; the population of beneficial bacteria such as lactobacilli increased in cecal contents of these mice. LAB were not detected in the peripheral blood, heart, liver, kidneys, and mesenteric lymph nodes after administration of this strain to intact mice. Lact. casei IMV B-7280 strain is safe at dose up to 10 10 CFU/animal during 3- and 7-day oral administration to mice and has a positive effect on the gut microbiota composition; it could be potentially considered as safe probiotic for humans.

Exopolysaccharide from Lactiplantibacillus plantarum YT013 and Its Apoptotic Activity on Gastric Cancer AGS Cells

“…In the other groups, the renal tubular epithelial cells of the mice were neatly arranged, the renal capsule was normal, and the renal corpuscle was uniform in texture. However, they evoked mild interstitial edema, which may be reversible [53]. Overall, histological studies in mice showed no abnormal or histopathological changes in tissues and organs.…”

Evaluation of the safety and immune stimulatory effects of multi-strain Lab Mix product on laboratory animals

“…Male BALB rats were orally dosed with L. casei IMVB-7280 at 5 × 10 6 , 5 × 10 8 , 5 × 10 9 CFU/day for 7 days or 1 × 10 10 CFU/day for 3 days, and a follow-up of 14 days. The survival rate of all mice was 100 %, and the weight remained unchanged [ 16 ]. The strain L. acidophilus was tested for its function against 1,2-dimethylhydrazine (DMH) and sodium dextran sulfate (DSS)-induced colon cancer in mice.…”

Enhancement of Immune Functions by Limosilactobacillus reuteri KBL346: In Vitro and In Vivo Studies

“…The mice were maintained in standard laboratory conditions (temperature 20–25 °C, humidity 50–60%, and 12 h light–dark cycle). Mice were randomly allocated to five groups: normal (N), cyclophosphamide (CPA) (CPA, Sigma-Aldrich Co.), red ginseng positive control (PC), and KBL346 at low (10 8 CFU/kg) and high (10 10 CFU/kg) dosages, as described previously with some modification [ 35 , 36 , 37 , 38 ]. The total duration of the animal experiment was 20 days.…”