BACKGROUND:The gut microbiota in our intestine performs numerous useful functions and has a major impact on the host’s health. Recently some studies have revealed that the gut microbiota cannot only control intestinal activity but also affect bone metabolism by regulating the immune system. OBJECTIVE:To review the new research development in the effects of gut microbiota on bone metabolism. METHODS: We retrieved the PubMed database using “gut microbiota, immune system, bone metabolism, osteoporosis” as keywords. A total of 46 articles were included which were related to gut microbiota, immune system and bone metabolism. For the articles in the same field, those published recently or in authorized journals were selected. RESULTS AND CONCLUSION:Gut microbiota-osteoporosis research wil bridge the gaps between bone physiology, gastroenterology, immunology, and microbiology.In vivo experiments in the germ-free mice and human body have found that the gut microbiota has important effects on bone metabolism, and the intervention of antibiotics, probiotics and prebiotics has further confirmed the effects of gut microbiota on bone mass. The gut microbiota has more obvious effects on bone mass in the adolescent and post-menopause periods.

BACKGROUND: Studies confirmed that pueraria can not only prevent the reduced bone mineral density and bone mass in the ovadectomy-caused estrogen deficiency mice with osteoporosis model, also improve bone micro-structure, it can be used for osteoporosis prevention and treatment in women after menopause. Does it exhibit a similar effect fpr the treatment of male osteoporosis?OBJECTIVE: To investigate the influence of puerariae Radix (PR) crude drug on the bone mineral density (BMD) and bone micro-architecture in androgen-deficiency mice with osteoporosis model.METHODS: A total of 48 ddY male mice, aged 8 weeks and weighing 32-35 g, were randomly divided into 6 groups: sham group,orchidectomized group, PR with low, middle and high dose group, 17β-estradiol group. Each group contained 8 mice. In sham group, mice were sham operated to expose testis and epididymis, removing surrounding fat tissue; in other groups, mice were orchidectomized. After operation, sham group and model group were fed normal diet, while PR with low, middle and high dose groups were fed a diet containing 5%, 10% and 20% PR, and 17β-estradiol group was fed a normal diet with subcutaneous administration of 17β-estradiol 0.03μg/d. The diet dosage was all 4.0 g/d. Four weeks after experiment, the mice were anesthetized and killed, and the weight of the seminal vesicle was measured. Dual-energy X-ray was used to detect BMD in femurs, and micro-CT analysis for distal femur metaphysis sponge bone microstructura.RESULTS AND CONCLUSION: The whole femoral BMD was significantly decreased by 10.9% in the model group, and the decrease in BMD was completely prevented by intake of the diet with the low dose of PR. Intake of the diet with the middle dose of PR further increased BMD in the model group, but no significant differences were observed. Furthermore, the high dose of PR administration significantly increased BMD by 26.1% and 12.4% respectively compared with model group and sham operated group, and the potency was similar to that of 17β-estradiol. Intake of the diet with the low dose of PR completely prevented the decrease in trabecular bone volume and trabecular number, and restored the increase in trabecular separation in mice caused by androgen deficiency. Intake of the diet with the middle dose of PR could enhance the inhibition effect, but there was no significant difference; intake of the diet with the high dose of PR exhibited the strongest effect on the inhibition, it further significantly increased trabecular bone volume and trabecular number compared with sham operated group. The seminal vesicle was not affected by the administration of any doses of PR. Without influence on the seminal vesicle, the low and middle dose of PR can completely inhibit the decreasing BMD and bone mass caused by androgen deficiency in mice, as well as improve bone structure,high dose of PR exhibits a significant effect and similar to 17β-estradiol.

OBJECTIVETo investigate the effects of isoflavone on body weight, fat mass, and gene expression in relation to lipid metabolism.

METHODSThirty-six female SD rats were ovariectomized or sham-operated and fed on a high-fat diet. Two months later, abdominal incision was made, blood was collected to separate serum, and the liver and adipose tissue were immediately collected and weighed. Some portions of these tissues were frozen in liquid nitrogen and stored at -80 degrees C.

RESULTSOvariectomy (OVX) with a high-fat diet could induce obesity in rats, while treatment with isoflavone significantly inhibited the increase in body weight and fat mass in abdomen. Serum total cholesterol and leptin were significantly decreased in isoflavone group, compared with the OVX group. The mRNA expression of liver fatty acid synthase (FAS) in the OVX group was significantly higher than that in sham-operated group, while this difference was not observed in the isoflavone group. The mRNA expression of liver hormone-sensitive lipase (HSL) in the OVX rats tended to be lower than that in the sham-operated rats. Furthermore, a large amount of isoflavone maintained the mRNA expression at a sham level.

CONCLUSIONIsoflavone may prevent obesity induced by ovariectomy with a high-fat diet, in part by modulating gene expression related to lipid metabolism.

Adipose Tissue ; Animals ; Body Composition ; Body Weight ; Dietary Fats ; metabolism ; Feeding Behavior ; Female ; Gene Expression Regulation ; drug effects ; Isoflavones ; pharmacology ; Lipid Metabolism ; drug effects ; Liver ; anatomy & histology ; Organ Size ; Ovariectomy ; Rats ; Rats, Sprague-Dawley

The present study aimed at investigating the effects of Puerarin (PR), a major isoflavonoid isolated from the Chinese medicinal herb Puerariae radix, on bone metabolism and the underlying mechanism of action. The in vivo assay, female mice were ovariectomized (OVX), and the OVX mice were fed with a diet containing low, middle, and high doses of PR (2, 4, and 8 mg·d(-1), respectively) or 17β-estradiol (E2, 0.03 μg·d(-1)) for 4 weeks. In OVX mice, the uterine weight declined, and intake of PR at any dose did not affect uterine weight, compared with the control. The total femoral bone mineral density (BMD) was significantly reduced by OVX, which was reversed by intake of the diet with PR at any dose, especially at the low dose. In the in vitro assay, RAW264.7 cells were used for studying the direct effect of PR on the formation of osteoclasts. PR reduced the formation of tartrate resistant acid phosphatase (TRAP)-positive multi-nucleated cells in the RAW 264.7 cells induced by receptor activator for nuclear factor-κB Ligand (RANKL). MC3T3-E1 cells were used for studying the effects of PR on the expression of osteoprotegerin (OPG) and RANKL mRNA expression in osteoblasts. The expression of OPG mRNA and RANKL mRNA was detected by RT-PCR on Days of 5, 7, 10, and 12 after PR exposure. PR time-dependently enhanced the expression of OPG mRNA and reduced the expression of RANKL mRNA in MC3T3-E1 cells. In conclusion, our results suggest that PR can effectively prevent bone loss in OVX mice without any hyperplastic effect on the uterus, and the antiosteoporosis activity of PR may be related to its effects on the formation of osteoclasts and the expression of RANKL OPG in osteoblasts.
Animals ; Bone Density ; drug effects ; Drugs, Chinese Herbal ; administration & dosage ; Female ; Femur ; chemistry ; growth & development ; metabolism ; Humans ; Isoflavones ; administration & dosage ; Mice ; Osteoclasts ; drug effects ; metabolism ; Osteoporosis ; genetics ; metabolism ; physiopathology ; prevention & control ; Osteoprotegerin ; genetics ; metabolism ; Ovariectomy ; Pueraria ; chemistry ; RANK Ligand ; genetics ; metabolism