RESUMO
PROBLEM: Estradiol (E2 ) deficiency can cause bone loss and the skew of Th1/Th2 cells. However, the correlation between the Th1/Th2 cells and the bone loss induced by estrogen deficiency remains unclear. Our aim was to investigate the role of Th1/Th2 in bone loss induced by estrogen deficiency and elucidated the therapeutical effect of catalpol in this condition. METHOD OF STUDY: Young, sham-operated (Sham), ovariectomized (Ovx), and naturally aged mice, treated with catalpol at different doses or control vehicle, were used in this study as indicated in each experiment. ELISA assay, dual-energy X-ray absorptiometry, and flow cytometry were used to analyze E2 , C-terminal telopeptides of type I collagen (CTx-I), bone mineral density (BMD), and Th1/Th2 subsets, respectively. The mRNA and protein expressions of specific transcription factors for Th1/Th2 cells (T-bet and GATA-3) were analyzed using real-time quantitative PCR and Western blot, respectively. RESULTS: Bone mineral density and E2 levels positively correlated with the proportion of Th2 subset while negatively correlated with that of Th1 subset and the ratio of Th1/Th2. Catalpol alleviated bone loss effectively by regulating Th1/Th2 polarization. Catalpol promoted the expression of Th2-specific transcription factors while inhibited that associated with Th1. CONCLUSION: Th1/Th2 skew is involved in bone loss induced by estrogen deficiency. Catalpol alleviates bone loss effectively by regulating Th1/Th2 paradigm.
Assuntos
Medicamentos de Ervas Chinesas/administração & dosagem , Estradiol/metabolismo , Glucosídeos Iridoides/administração & dosagem , Osteoporose/tratamento farmacológico , Células Th1/imunologia , Células Th2/imunologia , Animais , Células Cultivadas , Modelos Animais de Doenças , Feminino , Fator de Transcrição GATA3/genética , Fator de Transcrição GATA3/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Osteoporose/imunologia , Rehmannia/imunologia , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Equilíbrio Th1-Th2/efeitos dos fármacosRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Bone loss is a common pathological condition induced by estrogen deficiency. The Th17/Treg paradigm, which can be skewed by estrogen, plays an important role in regulating bone metabolism AIM OF THE STUDY: The purpose of this study was to determine the role of the Th17/Treg shift in estrogen deficiency-induced bone loss in mouse models and to elucidate the immunopharmacologic mechanism of Zuo-Gui-Wan (ZGW) in preventing bone loss in this process by regulating Th17/Treg paradigm. MATERIALS AND METHODS: Splenocytes of ovariectomized (Ovx) mice and naturally aged mice were isolated and Flow cytometry was used to detect the Th17/Treg subsets. In addition, serum estrodiol (E2) and serum C-terminal telopeptides of type Ι collagen (CTx) were detected by ELISA assay. Bone mineral density (BMD) of the left tibiae was measured by dual-energy X-ray absorptiometry. Moreover, Ovx mice were administrated with different doses of ZGW for 12 weeks, and BMD and Th17/Treg subsets were determined. Bone histomorphometry was observed by Hematoxylin and eosin (H&E) staining and serum protein levels of IL-6 were analyzed by ELISA assay. In addition, the mRNA and protein expression of RORγt and Foxp3 were detected by RT-PCR and Western blot respectively. RESULT: The Th17/Treg paradigm shifted to Th17 in estrogen-deficient mice both in the Ovx mice and the naturally aged mice. BMD and E2 levels negatively correlated with the Th17/Treg ratio. After ZGW administration, the BMD was enhanced markedly in the Ovx mice as well as in the naturally aged mice. Both the mRNA and protein expressions of IL-6 and RORγt were decreased, whereas those of Foxp3 were increased significantly after ZGW administration. CONCLUSION: Th17/Treg shift involved in the bone loss induced by estrogen deficiency. ZGW prevented bone loss efficiently and skewed Th17/Treg paradigm towards Treg without enhancing E2.