| Recent studies suggest that high-fat diet can not only lead to overweight,but also induce abnormal metabolism and absorption of bone,resulting in reduced bone mass and low bone strength,thus increasing the risk of spontaneous and traumatic bone injury.The abnormal of bone metabolism and resorption are affected by many factors,among which dietary factors play an important role in.However,the relationship between long-term high-fat diets and decreased bone performance has not been explained.The improvement of bone health by probiotics is mainly through the regulation of the immune system to affect the activity of osteoclast and to regulate the balance between bone resorption and bone remodeling.Therefore,we speculate that intestinal flora may be a new target for the treatment of osteoporosis.However,the specific relationship between probiotics,the immune system and bone health still needs to be further explored.In this paper,probiotic strains which have a significant inhibition of high-fat-diet induced obesity was selected to investigate its effect on the bone properties of obese mice.We investigate the relationship between intestinal microflora,colonic immune factors and fecal short chain fatty acids(SCFAs)in obese mice,and deduce the mechanism of probiotics on bone performance in obese mice.Then,it provides a new idea on developing a special probiotic which can inhibite obesity and protect bone health.Two Lactobacillus strains Lactobacillus paracasei subsp.Paracasei M5(M5),Lactobacillus coryniformis subsp.torquens T3(T3L)were administered to high-fat diet induced obesity mice at the dose of 109 CFU/m L.After 4 weeks,M5 and T3 L significantly decreased the body weight,body fat index and Lee’s index of mice(p < 0.05).We found that M5 and T3 L can significantly decreased the level of TG and TG in serm(p < 0.05).The results showed that M5 and T3 L strains could inhibit the obesity and blood lipids of mice caused by high-fat diets,of which T3 L was more effective.Lactobacillus had protective effect on bone health of obese mice: We measured the serum levels of ALP,TRAP and RANKL in mice,results showed that the levels were significantly reduced after T3 L supplement,which indicated that high-fat diets made the osteoclast activity active,bone resorption increased and it was improved by T3 L.T3L enhanced the biomechanical properties of femur,increased bone mineral content and improved the microstructure of femur in obese mice.RT-qPCR was used to detect the expression of related factors in mouse femur tissue.The results showed that the expression of RANKL and CTSK in the femur was significantly higher than that in the control group,and the expression was decreased significantly after administration with T3 L for 4 weeks(p <0.05).At the same time,the expression of COL1α1 with significantly increased by T3 L.High-throughput sequencing was used to detect the diversity of intestinal microorganisms.High-fat diets induced obesity made the intestinal flora different and it changed after T3 L administration,accompanied by an increase in short chain fatty acid bacteria.The expression of IL-10 in colonic tissue was significantly increased after administration with T3L(p <0.05).At the same time,the content of SCFAs in feces increased after T3 L administration.Probiotics may increase the proportion of short chain fatty acid bacteria by regulating the structure of intestinal flora,and thus the effect of short chain fatty acid on colonic immune function and the mechanism of bone remodeling can be used to protect bone.Lactobacillus may regulate the immune function of the colon by regulating the SCFAs,and then intervene the mechanism of bone remodeling to protect the bone. |
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