TGF-β1/Smad4信号通路对去卵巢骨质疏松大鼠骨髓微环境的影响及针刺干预机制

Effect of TGF-β1/Smad4 signaling pathway on bone marrow microenvironment in ovariectomized osteoporosis rats and mechanism of acupuncture intervention

目的研究TGF-β1/Smad4信号通路对去卵巢骨质疏松大鼠的影响,并分析针刺疗法对大鼠骨髓微环境的干预机制。方法选取SPF级雌性Wistar大鼠共60只,按照随机数字法分为空白组(A组)、模型组(B组)、针刺组(C组)和雌二醇组(D组),每组大鼠各15只。除A组外,其他大鼠均以去卵巢法建立骨质疏松症动物模型。造模成功后,C组交替给予电针刺激"肾俞穴""三阴交穴""关元穴"及"足三里穴",每次电针15 min,1次/d。D组按照人鼠等效剂量给予戊酸雌二醇治疗,总计干预治疗12周。对比分析各组大鼠血清中骨代谢相关标志物、股骨远端骨密度水平及骨小梁微结构变化;对比各组大鼠股骨远端骨组织中Runx 2、PPARγ、TGF-β1、Smad 4蛋白和mRNA表达水平。结果造模后,与空白组比较,各组大鼠骨密度均明显降低(P<0.05),血清中骨代谢标志物CBF-α1、BALP、PINP、OC、CTX-I含量均明显减少(P<0.05);相对骨体积分数(BV/TV)、骨小梁分离度(Tb.Sp)、骨小梁厚度(Tb.Th)、骨小梁数量(Tb.N)、连接密度(Conn.D)、结构模型指数(SMI)明显升高(P<0.05);股骨远端骨组织中Runx 2、PPARγ、TGF-β1、Smad 4蛋白和mRNA表达下降(P<0.05)。干预12周后,与模型组比较,雌二醇组和针刺组大鼠骨小梁微结构明显改善,骨密度、骨代谢标志物及股骨远端骨组织中Runx 2、PPARγ、TGF-β1、Smad 4蛋白和mRNA表达上升(P<0.05),其中针刺组明显优于雌二醇组(P<0.01)。结论针刺"肾俞穴""三阴交穴""关元穴"及"足三里穴"能够改善去卵巢大鼠骨髓微环境,改善骨小梁微结构,增加骨量,其机制可能与针刺疗法调控TGF-β1/Smad 4信号通路有关。

Objective To study the effect of TGF-β1/Smad4 signaling pathway on ovariectomized osteoporosis rats,and to analyze the intervention mechanism of acupuncture therapy on bone marrowmicroenvironment in rats.Methods A total of 60 SPF female Wistar rats were randomly divided into blank group(Group A),model group(Group B),acupuncture group(Group C)and estradiol group(Group D),with 15 rats in each group.Except Group A,other rats were ovariectomized to establish osteoporosis animal models.After the recipe was successfully modeled,Group C was alternately given electroacupuncture stimulation of"Shenshu""Sanyinjiao""Guanyuan"and"Zusanli",15 minutes each time,once a day.Group D was treated with estradiol valerate according to the equivalent dose of human and mice for 12 weeks.The changes of bone metabolism related markers in serum,bone mineral density and trabecular microstructure of distal femur were compared and analyzed;the expression levels of Runx2,PPARγ,TGF-β1,Smad4 protein and mRNA in bone tissue of distal femur were compared.Results After modeling,compared with the blank group,the bone mineral density of rats in each group was significantly decreased(P<0.05),and the serum levels of bone metabolism markers CBF-α1,BALP,PINP,OC,CTX-I were significantly increased(P<0.05);the relative bone volume fraction(BV/TV),bone trabecular separation(Tb.Sp),trabecular thickness(Tb.Th),the number of trabeculae(TB.N),connection density(Conn.d)and structural model index(SM I)were significantly increased(P<0.05);the expression of Runx 2,PPARγ,TGF-β1,Smad 4 protein and mRNA in distal femur decreased(P<0.05).After 12 weeks of intervention,compared with the model group,the microstructure of trabecular bone in the estradiol group and the acupuncture group was significantly improved,and the expressions of Runx 2,PPARγ,TGF-β1,Smad 4 protein and mRNA in the bone tissue of distal femur were increased(P<0.05),and the acupuncture group was significantly better than the estradiol group(P<0.01).Conclusion Acupuncture at"Shenshu""Sanyinjiao""Guanyuan"and"Zusanli"can improve bone marrowmicroenvironment,improve bone trabecular microstructure and increase bone mass in ovariectomized rats.The mechanism may be related to the regulation of TGF-β1/Smad 4 signaling pathway by acupuncture.