Effect And Mechanism Of α-zearalanol On The IL-6Expression And Secretion In Rat Osteoblasts

ObjectsTo investigate whether-zearalanol influences the IL-6expression and secretion in ratosteoblasts by different subtypes of estrogen receptor and provide new ways for preventionand treatment of postmenopausal osteoporosis.Methods:Osteoblasts were isolated from the skull of SD neonatal rats and identified bymorphological observation, ALP staining, and collagen I immunofluorescence staining.17-estradiol and-zearalanol with different concentrations were administrated. Theexpressions of IL-6, ER, ER mRNAs and proteins in the osteoblasts were detected byRT-PCR, Western blot and ELISA. Furthermore, the expression of altered estrogen receptorsubtype with-zearalanol application in rat osteoblasts was blocked by the way of RNAinterference, the estrogen receptor subtype specific siRNA gene was designed and synthesized,and then cloned into pSilencer3.1-H1-neo vector for constructing the recombinant plasmid,the recombinant plasmid was transfected into the rat osteoblasts. The expressions of IL-6mRNA and protein were measured in transfected osteoblasts by RT-PCR and ELISA after thetreatment of-zearalanol.Result:1. A-zearalanol with10-10~10-5mol/L concentrations could inhibit the expression andsecretion of IL-6and upregulate the expressions of ER mRNA and protein significantlyin osteoblasts, among which the concentration of10-6mol/L had the best effect.2. Compared with negative control group, the expressions of ER mRNA and protein had noobvious changes in different concentrations of-zearalanol treatment groups.3. The effect of-zearalanol on inhibiting the IL-6production wasn’t obvious in the ERsiRNA transfected rat osteoblasts.4.17-estradiol could increase the expressions of ER and ER in rat osteoblasts, and stillcould inhibit the expression of IL-6in ER siRNA transfected rat osteoblasts. Conclusion:The effect of17-estradio on inhibiting the IL-6production is problely mediated by bothER and ER. A-zearalanol has similarly inferior estrogen like effect in bone remodeling, itcan decrease the production of IL-6by ER in osteoblasts, and then influence the boneresorption by the way of inhibiting the formation and differentiation of osteoclast precursor,downregulating the activity of osteoclast. A-zearalanol may play an important role in theprevention and treatment of postmenopausal osteoporosis.