Mechanism of Bushen Huatan Prescription in Regulating Th17/Treg Balance in Ovariectomized Osteoporosis Rats / 中国实验方剂学杂志

ABSTRACT

Objective:To study the effect of Bushen Huatan prescription on helper T cell 17 （Th17）/T regulatory cells （Treg） balance of immune T cell subsets in the prevention and treatment of postmenopausal osteoporosis. Method:Sixty 6-month-old female SD rats were randomly divided into sham operation group， model group， estradiol valerate group （0.184 mg·kg^-1） and Bushen Huatan prescription low， medium and high groups （4.7， 9.4， 18.8 g·kg^-1） according to the random number table. All the groups except the sham operation group received ovariectomy to make postmenopausal osteoporosis model. Intragastric administration was started 1 week after operation， and the rats in model group and sham operation group received equal volume of normal saline， once a day for 12 weeks. Microcomputed tomography （Micro CT） was then used to detect bone mass and microstructure of rats， the contents of Forkhead box protein （Foxp3） and retinoic acid related nuclear orphan receptor （ROR<italic>γ</italic>t） in serum were detected by enzyme-linked immunosorbent assay （ELISA）， the mRNA expression levels of Foxp3 and ROR<italic>γ</italic>t in bone tissues were detected by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot was used to detect the protein expression of Foxp3 and ROR<italic>γ</italic>t in bone tissues， the number of Th17 and Treg cells in each group was analyzed and compared by flow cytometry. Result:Compared with the sham operation group， the bone mass and trabeculae of the model group decreased （<italic>P</italic><0.01）， the bone microstructure was destroyed， the concentration of Foxp3 in serum decreased， the concentration of ROR<italic>γ</italic>t increased （<italic>P</italic><0.01）， the mRNA and protein expression levels of Foxp3 in bone tissues decreased， ROR<italic>γ</italic>t increased， the number of Treg cells in bone tissues decreased， number of Th17 cells increased （<italic>P</italic><0.01）， and Th17/Treg ratio increased （<italic>P</italic><0.01） in model group. Compared with the model group， the bone mass in each treatment group increased （<italic>P</italic><0.05， <italic>P</italic><0.01）， Foxp3 concentration in serum increased， ROR<italic>γ</italic>t concentration decreased （<italic>P</italic><0.01）， the mRNA and protein expression levels of Foxp3 in bone tissues increased significantly （<italic>P</italic><0.05， <italic>P</italic><0.01）， but no statistical difference was shown in mRNA expression between low dose group and the model group. In addition， the mRNA and protein expression of ROR<italic>γ</italic>t decreased （<italic>P</italic><0.05， <italic>P</italic><0.01）， number of Treg cells increased， number of Th17 cells decreased （<italic>P</italic><0.05， <italic>P</italic><0.01）， and Th17/Treg ratio decreased in treatment groups （<italic>P</italic><0.01）. Conclusion:Bushen Huatan prescription can increase bone mass， improve bone microstructure， increase the number of Treg cells and decrease the number of Th17 cells in ovariectomized rats. It is concluded that Bushen Huatan prescription may play a role in preventing and treating postmenopausal osteoporosis by regulating Th17/Treg balance.