Study Of Correlation Between Structural Characteristics Of Gut Microbiota And TH17/Treg Ratio In Osteoporosis

ObjectiveTo study the structural characteristics of gut microbiota in patients with osteoporosis and the correlation among TH17/Treg ratio,bone mineral density and gut microbiota.MethodsA case control study was adopted for this experiment.Volunteers were selected from the endocrinology clinic,trauma orthopedic clinic and spine surgery clinic of Zhujiang Hospital of Southern Medical University from May 2018 to December 2018.According to the dual-energy X-ray absorptiometry and history of fragility fractures,volunteers were divided into normal bone mass group,low bone mass group and osteoporosis group.The age,gender,venous serum glucose,electrolytes,and bone metabolism related indicators of the three groups were analyzed.The venous blood of volunteers were collected,and the levels of TH17 and Treg cells in peripheral blood were detected by flow cytometry.The fecal samples of volunteers were collected,and the bacterial genomic DNA were extracted by SDS method.The 16S V4,18S V4,18S V9 and ITS1 regions of bacterial DNA were amplified by specific primers with barcode,high-performance and high-fidelity DNA polymerase.The sequencing was analyzed by Uparse software,MUSCLE software,Qiime software and R software.SPSS20.0 was used to analyze the statistical difference between groupsResultsIn this study,17 volunteers with normal bone mass,9 volunteers with low bone mass,and 12 volunteers with osteoporosis were included.The age of the osteoporosis group was higher than those in the normal bone mass group(P<0.01).The gender difference between the three groups was statistically significant(P<0.05).There was significant difference in the TH17/Treg cell ratio among the three groups(P<0.05).There was no significant correlation between TH17/Treg cell ratio and age(P>0.05).There was no significant correlation between TH17/Treg cell ratio and gender(P>0.05).The remaining general clinical data were not statistically different among the three groups.The OTUs(Operational Taxonomic Units)of three groups overlapped each other.There was no significant difference in the Alpha diversity index among the three groups.The abundance of intestinal Klebsiella in the low bone mass group was higher than that in the normal bone group(P<0.05).The abundance of intestinal Ruminococcus in the normal bone mass group was higher than that in the low bone mass group(P<0.05)and the osteoporosis group(P<0.05).The LDA bar graph suggested that the abundance of Enterococcus in the osteoporosis group and the low bone mass group was higher than that in the normal bone mass group.Spearman correlation analysis showed that both Klebsiella and Enterococcus were positively correlated with TH17/Treg cell ratio(P<0.01),and negatively correlated with bone mineral density(P<0.05).The abundance of Ruminococcus was negatively correlated with the ratio of TH17/Treg cells(P<0.05),and positively correlated with bone mineral density(P<0.05).These three bacteria have no significant correlation with blood glucose and age.ConclusionThe overall gut microbiota composition of patients with osteoporosis is similar to those with normal bone mass,but the abundances of some gut microbiota are different from normal population.There were significant differences in the abundance of Klebsiella,Enterococcus and Ruminococcus in the group with abnormal bone metabolism and the group with normal bone mass.Based on the results of this study,we hypothesized that Klebsiella,Enterococcus and Ruminococcus can regulate bone metabolism by affecting the balance of peripheral blood TH17 cells and Treg cells.