【作者】 王燕；

【导师】 徐进；

【作者基本信息】 山东大学 ， 内科学（内分泌与代谢病）（专业学位）， 2020， 博士

【摘要】 研究背景:骨质疏松症(osteoporosis,OP)是多种原因导致的以骨量减少和骨微组织结构破坏为特征,引起骨的强度下降和脆性增加从而易于发生骨折的一种代谢性骨病。OP导致的骨折严重影响人们的生活质量,尤其是髋骨骨折是最为严重的骨折,其致残率及致死率极高。每年治疗OP花费巨大,给家庭、社会均带来沉重负担。所以探索OP的相关危险因素及有效干预措施始终是摆在研究者面前的重大课题。在OP的众多影响因素中,肥胖与OP的相关性越来越引起人们的关注,但研究结论存在争议。既往的多项研究提示肥胖对OP是一种保护作用,但随着研究的增多出现了不同的结果,发现肥胖可能与低骨量及骨折风险升高有关。肥胖患者会增加高血压、糖尿病、心血管及癌症等疾病的发病率,这与人群预期寿命缩短相关。但不是所有的肥胖患者都具有相同的风险,相同的体重指数(body mass index,BMI)其代谢状况异质性很大。结合代谢状况及BMI可将研究对象分为正常体重代谢正常(metabolically healthy normal weight,MHNW)组,正常体重代谢异常(metabolically unhealthy but normal weight MUNW)组,肥胖代谢正常(metabolically healthy obese,MHO)组及肥胖代谢异常(metabolically unhealthy obese,MUO)组。已有研究证实根据代谢状况区分的不同肥胖亚型可以更精确的预测代谢性疾病的相关风险。虽然越来越多的研究提示代谢因素与骨骼健康密切相关,但目前尚缺乏将代谢状况考虑其中的肥胖亚型分型与骨健康关系的研究。目前对于OP的研究更多见于女性,鉴于男性OP人群逐年增加的现状,男性的骨骼健康更需引起人们的重视。本研究旨在探讨不同代谢状态的肥胖人群与前臂骨密度(bone mineral density,BMD)的相关性,从而为男性OP的精准防治提供一定的理论依据。目的:本文通过分析中国北方男性人群的前臂BMD状况及其可能的危险因素,探索男性肥胖与骨健康的相关性,为男性OP的精准防治提供一定理论依据。研究方法:本研究数据来自山东大学附属省立医院2009-2010年在济南市舜耕区和槐荫区进行的流行病学调查研究。根据入组与排除标准,850名男性被纳入研究进行数据分析。采用两种肥胖分组方法进行分析:一是根据世界卫生组织(World Health Organization,WHO)标准分组为:体重正常组、超重组及肥胖组。二是根据BMI、代谢综合征(metabolic syndrome,MetS)及胰岛素抵抗指数(insulin resistance index,HOMA-IR)将人群分组为 MHNW 组、MUNW 组、MHO 组及MUO组。采用协方差分析对比各组间前臂骨密度差异。协因子包括年龄、身高及体重。偏相关及多元线性回归分析前臂BMD与临床相关因素的相关性。结果:1.研究人群的基本资料WHO分组中年龄、身高、吸烟在三组间比较无差异(P>0.05)。超重和肥胖组的体重、BMI、腰围(waistcircumference,WC)、收缩压、舒张压、高密度脂蛋白(high-denstiy lipoprotein cholesterol,HDL-c)、总胆固醇(total cholesterol,TC)、胰岛素(insulin,INS)、低密度脂蛋白(low-denstiy lipoprotein cholesterol,LDL-c)、空腹血糖(fastingblood glucose,FBG)、甘油三酯triglyceride,TG)及HOMA-IR均高于正常体重组(P<0.05或0.01)。结合代谢状况及BMI分组中,MHNW组与MUNW组相比,MUNW组的体重、BMI、WC、收缩压、舒张压、HDL-c、TG、INS、FBG 及 HOMA-IR 均明显升高(P<0.05或0.01),而TC、LDL-c、年龄、身高和吸烟在组间无差异(P>0.05)。MHO组与MUO组相比,MUO组的体重、BMI、WC、收缩压、舒张压、TC、HDL-c、LDL-c、TG、INS、FBG 及 HOMA-IR 均明显升高(P<0.05或0.01),年龄、身高和吸烟组间无差异(P>0.05)。2.不同分组后各组间前臂BMD比较(1)WHO分组中各组间前臂BMD比较WHO分组中超重及肥胖男性的前臂BMD均高于正常体重男性的前臂BMD(P<0.01)。校正年龄、身高、体重后,组间差异无显著性(P>0.05)。在中青年组中,超重及肥胖男性的前臂BMD均高于正常体重男性的前臂BMD(P<0.01)。校正协因子后,组间差异无显著性(P>0.05)。老年组超重男性的前臂BMD高于正常体重男性的前臂BMD(P<0.01),校正协因子后,超重组及正常体重组组间差异无意义(P>0.05)。肥胖组的前臂BMD高于正常体重男性的前臂BMD,但差异无显著(P>0.05)。(2)结合代谢状态及BMI分组后各组间前臂BMD比较MHO组的前臂BMD高于MHNW组、MUNW组及MUO组的前臂BMD(均P<0.01),MUO组的前臂BMD高于MHNW组及MUNW组的前臂BMD(P<0.05 或 0.01),MHNW 组及 MUNW 组间前臂 BMD 无差异(P>0.05)。校正年龄、身高、体重后,MHO组的前臂BMD仍高于MUO组的前臂BMD(P<0.01),余组间差异无统计学意义(P>0.05)。中青年组中MHO组的前臂BMD高于MHNW组及MUO组的前臂BMD(P<0.01或0.05)。校正年龄、身高及体重后,MHO组的前臂BMD仍高于MUO组的前臂BMD(P<0.01),与MHNW组的前臂BMD相比差异无统计学意义(P>0.05)。老年组中MHO组的前臂BMD高于MHNW组及MUNW组的前臂BMD(均P<0.01),MUO组的前臂BMD高于MHNW组及MUNW组的前臂BMD(P<0.01或0.05)。校正年龄、身高、体重后,MHO组的前臂BMD高于MHNW组及MUNW组的前臂BMD(P<0.05),MUO组的前臂BMD与MHNW组及MUNW组的前臂BMD无统计学差异(P>0.05)。3、相关分析及多元回归分析结合代谢状况及BMI分组的中青年组中对肥胖人群校正年龄、身高、体重的偏相关分析示前臂BMD与WC、LDL-c、INS及HOMA-IR呈负相关。多元回归分析示,HOMA-IR与前臂BMD呈负相关。结论:1、仅根据BMI定义肥胖时(WHO标准),体重是预测中青年男性人群前臂骨密度的良好因子。2、当综合代谢状况及BMI对肥胖人群进行亚组分析时,不同代谢状况的肥胖人群骨健康状况是不同的:①在中青年人群中,肥胖代谢正常人群的前臂骨密度高于肥胖代谢异常人群的前臂骨密度。②在老年人群中,肥胖正常代谢人群的前臂骨密度高于体重正常人群的前臂骨密度。3、中青年肥胖人群中HOMA-IR是前臂骨密度的负性相关因子。研究背景:随着现代社会的发展,肥胖及OP(osteoporosis,OP)的相关性已越来越引起人们的关注。荟萃分析显示超重及肥胖儿童的骨密度高于正常体重儿童的骨密度,但儿童期的超重及肥胖对成年期骨健康的影响并不明确。也有不同的研究指出超重及肥胖儿童的骨折风险高于正常体重儿童。本研究第一部分我们对成年男性流行病学调查数据分析发现肥胖男性的骨密度高于正常体重人群的骨密度,校正体重后差异无统计学意义。骨骼健康不仅包括骨密度,还包括骨强度等其他指标,因此肥胖人群的骨健康状况有待进一步确认。在肥胖人群中肥胖代谢异常者占75%以上,本实验予以高脂饮食诱导了代谢异常的肥胖雄性SD大鼠并观察青少年期及成年期的骨骼健康状况。目前用于减重及改善肥胖患者代谢状况的临床药物未见明确有益于骨健康的报道。小檗碱(berberine,BBR)是黄连中提取的生物碱,具有降糖、调脂、止泻、抗菌、抗炎、抗肿瘤等多种药理学作用。另外,有调查研究提示BBR能改善某些OP动物模型的骨骼健康状况。但BBR对代谢异常肥胖者骨代谢的影响,国内外未见报道。因此,本研究设计动物实验观察BBR是否可以影响代谢异常的肥胖雄性SD大鼠的骨健康状况。目的:1、观察代谢异常的肥胖雄性SD大鼠青少年期及成年期的骨代谢的变化,包括血钙(calcium,Ca)、磷(phosphorus,P)、骨形成标志物、骨吸收标志物、炎性指标、骨密度、骨微结构、骨生物力学等。2、观察BBR对代谢异常肥胖雄性SD大鼠骨代谢的影响。研究方法:4周龄雄性SD大鼠50只,适应性喂养1周后,随机分成普食组(ND组,n=20)和高脂组(HFD组,n=30),每周测体重。17周龄高脂组大鼠的体重及体脂率明显高于普食组,提示肥胖造模成功。然后再将高脂组的大鼠随机分为高脂+BBR组(HB组,n=10)(连续10周腹腔注射BBR 3mg/kg/d)和高脂组(HFD组,n=10)(腹腔注射等量二甲基亚砜)。动态观察肥胖雄性SD大鼠17周龄(青少年期)、27周龄(成年期)骨代谢的变化,同时观察BBR对肥胖雄性SD大鼠骨代谢的影响。大鼠在17周龄行体成分分析及腹腔葡萄糖耐量试验(intraperitoneal glucose tolerance test,IPGTT)和腹腔胰岛素耐量实验(intraperitoneal insulin tolerance test,IPITT),HFD组大鼠血糖明显高于ND组大鼠,提示肥胖组大鼠合并代谢异常。两组各取10只大鼠禁食12小时后麻醉状态下取血,室温离心血清,检测各组Ca、P、骨形成标志物1型原胶原N端前肽(type 1 N-terminal propeptide,P1NP)、骨吸收标志物 1 型胶原 C末端(c-telopeptide of type 1 collagen,CTX-1)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)水平、白介素 1 β(interleukin-1β,IL-1β),对左股骨行三点弯曲试验,对右股骨行微计算机断层扫描技术(micro computed tomography,microCT)检查。BBR 干预 10 周后,麻醉处死27周龄SD大鼠,取血清检测Ca、P、IL-1β、TNF-α、骨形成标志物PINP及骨吸收标志物CTX-1;三点弯曲实验评估股骨骨强度变化;microCT检查评估股骨骨微结构变化;HE染色观察胫骨骨小梁数目和脂肪细胞数目。结果:1、青少年期肥胖雄性SD大鼠体成分、IPGTT及IPITT实验结果(1)青少年期肥胖雄性SD大鼠体成分结果高脂喂养12周后,与ND组相比,HFD组体重、全身脂肪百分比均明显增加(P<0.01)。HFD组雄性SD大鼠的体重较ND组雄性SD大鼠体重增加21.2%。此实验提示高脂诱导的肥胖雄性SD大鼠造模成功。(2)青少年期肥胖雄性SD大鼠的IPGTT及IPITT实验结果青少年期肥胖雄性SD大鼠在IPGTT和IPITT实验中血糖水平显著高于ND组大鼠的血糖水平(P<0.01)。在IPITT实验中提示青少年期肥胖雄性SD大鼠对胰岛素的敏感性显著低于ND组大鼠。该实验提示肥胖SD大鼠合并糖耐量异常且胰岛素敏感性下降。2、青少年期肥胖雄性SD大鼠的骨密度、骨微结构及骨生物力学结果与ND组比较,肥胖SD大鼠的全身骨密度、左股骨骨密度、脊柱骨密度均有所升高(均P<0.05)。校正体重后,两组间比较差异均无统计学差异(均P>0.05)。与ND组相比,肥胖SD大鼠的小梁骨结构参数如骨小梁体积骨密度(Tb.vBMD)、骨小梁骨体积分数(Tb.BV/TV)及骨小梁数目(Tb.N)均明显下降(均P<0.05),骨小梁分离度(Tb.Sp)明显升高(P<0.05)。皮质骨体积骨密度(Ct.vBMD)、皮质骨骨体积分数(Ct.BV/TV)和皮质骨厚度(Ct.Th)两组间比较无统计学差异(均P>0.05)。与ND组相比,青少年期肥胖SD大鼠的骨生物力学两组间差异无统计学意义(均 P>0.05)。3、BBR能改善成年期肥胖雄性SD大鼠的糖脂代谢状况。(1)BBR改善成年期肥胖雄性SD大鼠糖代谢状况腹腔注射BBR10周后,成年期肥胖雄性SD大鼠在IPGTT和IPITT实验中血糖水平显著高于ND组大鼠的血糖水平(均P<0.01),而HB组大鼠在IPGTT和IPITT实验中血糖水平得到了明显改善(均P<0.05)。(2)BBR改善成年期肥胖雄性SD大鼠肝酯水平,并可以降低肥胖雄性SD大鼠骨髓脂肪含量肥胖SD大鼠肝脏的总胆固醇、游离胆固醇及甘油三酯水平均显著高于ND组大鼠(均P<0.01)。HB组肝脏的甘油三酯水平较肥胖组SD大鼠明显下降(P<0.01),胆固醇及游离胆固醇水平有所下降,但差异无统计学意义(P>0.05)。胫骨HE染色结果提示,与ND组比较,成年期肥胖雄性SD大鼠的胫骨骨髓脂肪细胞数目明显增加(P<0.01);与肥胖大鼠比较,HB组大鼠的骨髓脂肪细胞数量明显减少(P<0.01)。4、BBR对肥胖雄性SD大鼠Ca、P、骨代谢标志物(P1NP和CTX-1)、炎性因子(IL-1β、TNF-α)的影响各组间血Ca、P水平无差异(均P>0.05)。青少年期及成年期肥胖大鼠与ND组比较P1NP组间无统计学差异(均P>0.05)。与肥胖大鼠比较,HB组P1NP有所升高(P<0.05)。与ND大鼠比较,成年期肥胖组大鼠CTX-1有所升高(P<0.05)。HB组较肥胖组的CTX-1有所下降,但无统计学差异(P>0.05)。青少年期及成年期肥胖大鼠的炎性因子IL-1β、TNF-α较ND组均有所升高(均P<0.05,P<0.01)。与肥胖大鼠相比,HB组IL-1β、TNF-α均有所降低(均P<0.01)。5、BBR改善成年期肥胖雄性SD大鼠骨生物力学损伤与ND组相比,成年期肥胖大鼠的最大负荷、最大断裂负荷、韧性、能量吸收和极限拉伸强度均降低(P<0.01或0.05)。与肥胖大鼠相比较,HB组最大负荷、最大断裂负荷、韧性及能量吸收均有所改善(P<0.01或0.05),极限拉伸强度、弹性模量有所改善,但差异无统计学意义(均P>0.05)。6、BBR可改善成年期肥胖雄性SD大鼠骨微结构损害与ND组相比,肥胖SD大鼠的骨小梁体积骨密度(Tb.vBMD)、骨小梁骨体积分数(Tb.BV/TV)、骨小梁厚度(Tb.Th)及骨小梁数目(Tb.N)显著降低(P<0.01),结构模式指数(SMI)和骨小梁分离度(Tb.Sp)显著增加(P<0.01)。与肥胖大鼠比较,HB组的骨小梁体积骨密度(Tb.vBMD)、骨小梁骨体积分数(Tb.BV/TV)、骨小梁数目(Tb.N)、骨小梁分离度(Tb.Sp)及结构模式指数(SMI)均所有改善,但差异无统计学意义(P>0.05)。皮质骨体积骨密度(Ct.vBMD)、皮质骨骨体积分数(Ct.BV/TV)和皮质骨厚度(Ct.Th)在三组大鼠间比较均无统计学差异(均P>0.05)。胫骨HE染色结果提示,与ND组比较,肥胖大鼠的骨小梁数目明显减少(P<0.01)。结论:1、高脂喂养12周的雄性SD大鼠体重及体脂明显增加。肥胖大鼠的炎性指标较对照组大鼠明显升高。肥胖雄性SD大鼠存在糖耐量异常且胰岛素敏感性下降。2、青少年期肥胖雄性SD大鼠已经出现小梁骨的损伤,但骨强度无明显变化。成年期肥胖大鼠的破骨细胞标志物明显升高,小梁骨骨损伤进一步加重,并出现了骨强度的下降。3、BBR可以改善肥胖雄性SD大鼠的糖代谢状况及胰岛素抵抗,改善炎性指标,降低肝脏甘油三酯水平及减少骨髓脂肪细胞数目。4、BBR可以升高P1NP,降低CTX-1,骨微结构及骨强度均有所改善,骨强度为著。更多还原

【Abstract】 Background:Osteoporosis(OP)is a metabolic bone disorder caused by a variety of reasons,characterized by decreased bone mass,microarchitectural deterioration,resulting in decreased bone strength and prone to fragility fractures.People’s quality of life is affected by fractures associated with OP.The most serious fracture is hip fracture,which can lead to high disability rate and mortality rate.It is extremely expensive to treat osteoporosis every year,which brings heavy burden to the family and society.Therefore,it is a question for researchers to explore the risk factors of OP and effective intervention measures.The relationship between obesity and OP has attracted more and more attentions among many affecting factors of OP,but conclusions are controversial.Various studies have shown a protective role of obesity against osteoporosis.With the increasing of research,different results have emerged.Recent evidence suggests obesity may be a risk factor for low bone mass and related fractures.Obese individuals have a high risk of developing hypertension,diabetes mellitus,cardiovascular disease,dyslipidaemia and many other diseases.That is why obesity can reduce life expectancy.But not all obesity have the same risk for related diseases.Individuals in the same body mass index(BMI)category can have substantial heterogeneity of metabolic features.According to metabolic status and BMI,the population can be divided into metabolically healthy normal weight(MHNW)group,metabolically unhealthy but normal weight(MNNW)group,metabolically healthy obese(MHO)group and metabolically unhealthy obese(MUO)group.Studies have indicated that the different obesity subtypes based on metabolic status may be an indicator that can be used to predict the risk of some chronic diseases.Moreover,increasing evidences show that metabolic status are related to bone health.However,these data could not encompass the relationship between bone health and obesity subtypes taking metabolic status into accout.At present,most research on osteoporosis is related to women.With the increasing of OP in men year by year,we should pay more attention to the bone health of men.The purpose of this study is to investigate the relationship between obesity and forearm BMD in different metabolic status to provide theoretical basis for the precise prevention and treatment of OP.Objectives:To analyze the forearm bone mineral density(BMD)and its possible risk factors in a northern Chinese population and explore the relationship between obesity and bone health for providing theoretical basis for the precise prevention and treatment of OP in men.Methods:Data were from epidemiological investigation in Shungeng and Huaiyin communities of Jinan city in China,which were organized by Provincial Hospital affiliated to Shandong Universtity from 2009 to 2010.According to the inclusion and exclusion criteria,850 men were enrolled in the study.According to criteria of World Health Organization(WHO),individuals were divided into normal weight group,overweight group and obesity group.According to BMI,metabolic syndrome(MetS)and insulin resistance index(HOMA-IR),the population were divided into MHNW group,MNNW group,MHO group and MUO group.Analysis of covariance was performed to compare forearm BMD among the groups.The covariates included age,height,weight.Partial correlation analysis and multiple linear regression models were used to explore the association between forearm BMD and clinical parameters.Results:1.Baseline characteristics of subjectsIn the WHO group,no significant differences were found in age,height and smoking among the three groups(P>0.05).Weight,BMI,waist circumference(WC),systolic blood pressure,diastolic blood pressure,high-density lipoprotein(HDL-c),total cholesterol(TC),insulin(INS),low-density lipoprotein(LDL-c),fasting blood glucose(FBG),triglyceride(TG)and HOMA-IR in the overweight and obesity group were higher than that in the normal weight group(P<0.05 or 0.01).When taking metabolic status and BMI into accout for subtype analysis,Weight,BMI,WC,systolic blood pressure,diastolic blood pressure,HDL-c,TG,INS,FBG and HOMA-IR in MUNW group were higher than that in the MHNW group(P<0.05 or 0.01),but there was no difference in TC,LDL-c,age,height and smoking(P>0.05).Higher weight,BMI,WC,systolic blood pressure,diastolic blood pressure,TC,HDL-c,LDL-c,TG,INS,FBG and HOMA-IR were observed in MUO group than those in MHO group(P<0.05 or 0.01).No significant difflerences were found in age,height and smoking between MHO group and MUO group(P>0.05).2.Variation in forearm BMD among different groups(1)Variation in forearm BMD among different groups in WHO criteriaSubjects in overweight and obesity group have higher forearm BMD than normal weight participants in crude(P<0.01),no significant differences were found after adjusting age,height and weight(P>0.05).In middle-young-aged group,individuals in overweight and obesity group have higher forearm BMD than normal weight participants in crude(P<0.01),no significant differences were found after adjusting age,height and weight(P>0.05).In aged group,overweight group has higher forearm BMD than normal weight participants in crude(P<0.01),no significant differences between overweight group and normal weight group were found after adjusting age,height and weight(P>0.05).Obesity also has higher forearm higher forearm BMD than normal weight participants in crude,but there is no difference(P>0.05).(2)Variation in forearm BMD among different groups divided by metabolic status and BMIIn crude,MHO individuals had higher forearm BMD than subjects with MHNW、MUNW and MUO(all P<0.01),MUO individuals had higher forearm BMD than subjects with MHNW and MUNW(P<0.05 or 0.01).No significant difference was found between MHNW group and MUNW group.After adjusting age,height and weight,MHO group had higher forearm BMD than subjects with MUO,there were no significant differences among other groups(P>0.05).Middle-young-aged men with MHO had higher forearm BMD than subjects with MHNW and MUO in crude(P<0.01 or 0.05).After adjusting age,height and weight,MHO group had higher forearm BMD than subjects with MUO(P<0.01),no significant differences were found compared with MHNW group(P>0.05).Aged subjects with MHO had higher forearm BMD than subjects with MHNW and MUNW in crude(all P<0.01),same is true compared MUO group with MHNW and MUNW group(P<0.01 or 0.05).After adjusting age,height and weight,MHO group had higher forearm BMD than subjects with MHNW and MUNW(P<0.05).There were no significant differences compared MUO group with MHNW and MUNW group(P>0.05).3.Partial correlation analysis and multiple linear regressionAge-,height-,and weight-adjusted partial correlation analyses showed that WC,LDL-c,INS and HOMA-IR were negatively correlated with forearm BMD in middle-young-aged obese men.Multiple regression analyses presents HOMA-IR showed significant negative relationship with forearm BMD in middle-young-aged obese men.Conclusions:1.When obesity is defined only by BMI(WHO standard),weight is a good predictor for forearm BMD in middle-young-aged men.2.When taking metabolic status and BMI into accout for subgroup analysis of obesity,the bone health status of obesity with different metabolic status were different.①Obesity with normal metabolism in middle-young-aged men had higher forearm BMD than obesity with abnormal metabolism.②Obesity with normal metabolism in aged men had higher forearm BMD than subjects with normal weight.3.HOMA-IR is a negative predictor of forearm BMD in middle-young-aged obese men.Background:With the development of modern society,the relationship between obesity and osteoporosis(OP)has attracted more and more attentions.Meta analysis showed that the bone mineral density(BMD)of overweight and obese children was higher than that of normal weight children,but the long-term impact of childhood overweight and obesity on bone health at adulthood is not clear.Different study has shown that overweight and obese children have a higher risk of fracture than normal weight children.In part one of the study,after analysis of adult male epidemiological survey data,we found BMD in obesity is higher than that in normal weight,but no difference was found after adjusting for weight.Considering the bone health include not only BMD but also other indicators such as bone strength,the bone health status in obesity needs to be further confirmed.Over 75%of obese people have abnormal metabolism.In this study,obese male SD rats with abnormal metabolism were induced by high-fat diet,and the bone health status in juvenile and adulthood were observed.At present,the benefits for bone health have not been found in the use of drugs to lose weight and improve the metabolic status in obese patients.Berberine(BBR)is a main alkaloid purified from rhizoma coptidis.It has numerous positive effects,including those on blood glucose,blood lipids,antidiarrheal and antibacterial,as well as anti-inflammatory,antitumor et al.In addition,data showed that BBR could improve bone health in some OP animal models.However,the effects of BBR on bone metabolism in obesity with abnormal metabolism has not been reported at home and abroad.This study aims to evaluate the effects of BBR on bone health in obese rats with abnormal metabolism.Objectives:1.To observe the bone metabolism of obese male Sparague Dawley(SD)rats with abnormal metabolism in juvenile and adulthood,including serum calcium(Ca),phosphorus(P),bone formation markers,bone resorption markers,inflammatory indicators,BMD,bone microstructure,bone biomechanical properties et al.2.To observe the effects of BBR on bone metabolism in obese male SD rats with abnormal metabolism.Methods:After acclimatized for 1 week,50 male SD rats(4-week-old)were randomly assigned to one of two diets:normal control diet(ND group,n=20)or high fat diet(HFD group,n=30).Body weight were tested weekly.HFD-induce obese models were successfully established,when body weight and fat percentage of rats in HFD group were significantly higher compared with that in ND group.Then these rats were randomly divided into HFD diet+BBR group(HB group,n=10)and HFD group(HFD diet,n=10),which were respectively intraperitoneally administrated with BBR at a dose of 3mg/kg or equivalent volume of dimethyl sulfoxide(DMSO)once a day for another 10 weeks.Meanwhile,Rats ND group were intraperitoneally administrated with the same volume of DMSO like those in HFD group.Dynamically observe bone health of obese male SD rats in juvenile and adulthood and observe the effects of BBR on bone health in obese male SD rats.Body composition,intraperitoneal glucose tolerance test(IPGTT)and intraperitoneal insulin tolerance test(IPITT)was measured when rats were at 17 week olds.The blood glucose levels of IPGTT and IPITT in obese male SD rats of juvenile were significantly higher than that of ND group,which suggests obese rats with abnormal metabolism.After being starved for 12 h,the rats(n=10)were anesthetized and sacrificed.The serum was centrifuged at room temperature to test Ca,P,bone formation markers type 1 N-terminal propeptide(P1NP),bone resorption markers c-telopeptide of type 1 collagen(CTX-1),interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α).Three-point bending test was performed on the left femur.Micro computed tomography(microCT)examination was conducted on the right femur to observe changes in bone microstructure.After 10 weeks of BBR intervention,the rats at 27 week olds were anesthetized and sacrificed.The serum was collected to test Ca,P,P1NP,CTX-1,IL-1β and TNF-α.Three-point bending test was conducted on the left femur to oberserve bone strength.Bone microarchitecture was investigated by microCT examination on the right femur.Left tibias were stained with HE to observe the number of trabecular and bone marrow adipocytes.Results:1.Body composition,IPGTT and IPITT of obese male SD rats in juvenile(1)Body weight and body composition of obese male SD rats in juvenileRats in HFD group had higher body weight and total fat percentage at the end of 12 week in comparison with ND diet(P<0.01).Body weight in HFD group increased 21.2%compared with that in ND group at the end of 12 weeks.HFD-induce obese male SD rat models were successfully established.(2)IPGTT and IPITT in obese male SD rats in juvenileThe blood glucose levels of IPGTT and IPITT in obese male SD rats of juvenile were significantly higher than that of ND group(P<0.01).The results in IPITT showed insulin sensitivity was significantly declined in obese male SD rats of juvenile compared with ND group.Results show that abnormal glucose tolerlance and low insulin sensitivity in obese rats.2.BMD,bone microstructure and biomechanical properties in obese male SD rats in juvenileWhole body BMD,left femur BMD and spinal BMD in obese rats were significantly higher compared with ND group(all P<0.05).No significant differences were found between them after adjusting weight(all P>0.05).The trabecular Volume bone mineral density(Tb.vBMD),trabecular bone volume/total volume(Tb.BV/TV),trabecular number(Tb.N)were decreased(all P<0.05)and the trabecular separation(Tb.Sp)was increased(P<0.05)in obese rats compared with the ND group.Meanwhile,the cortical volume bone mineral density(Ct.vBMD),cortical bone volume/total volume(Ct.BV/TV)and cortical bone thickness(Ct.Th)had no significant differences between two groups(all P>0.05).No significant differences were found in the maximum load,maximum fracture load,ultimate tensile strength,stiffness,energy absorption,and elastic modulus between two groups in juvenile(all P>0.05).3.BBR improved glucose and lipid metabolism properties in adult obese male SD rats(1)BBR improved glucose metabolism in adult obese male SD ratsAfter 10 weeks of BBR intervention,the blood glucose levels of IPGTT and IPITT in adult obese male SD rats were significantly higher than that of ND group(all P<0.05).However,SD rats in HB group displayed lower levels of blood glucose throughout the IPGTT and IPITT compare with the obese rats(all P<0.05).(2)BBR improved hepatic ester level and decreased the number of bone marrow adipocytes in adult obese male SD ratsHepatic total cholesteryl,free cholesteryl and triglyceride ester in adult obese male SD rats were significantly higher than that of ND group(all P<0.01).However,SD rats in HB group displayed lower levels of hepatic triglyceride ester compared with the obese rats(P<0.01),hepatic total cholesteryl and free cholesteryl hepatic total cholesteryl,free Cholesteryl and triglyceride ester decreased,but there was no significant difference(P>0.05).The results of HE staining in the left tibia samples showed the number of bone marrow adipocytes in obese rats was increased compared with the ND group(p<0.01),while it was dramatically decreased in the HB group compared with obese rats(p<0.01).4.Effects of BBR on Ca,P,bone metabolic index(PlNP and CTX-1),inflammatory marker(IL-1β,TNF-α)NO significant difference were found in Ca,P among three groups(all P>0.05).The bone formation markers P1NP were not changed between obese rats and the ND group in juvenile and adult.Compared with obese rats,P1NP was increased in the HB group(P<0.05).Compared with the ND group,CTX-1 was increased in adult obese rats(P<0.05).Though CTX-1 was decreased in the HB group than that in adult obese rats,there was no significant(P>0.05).Compared with the ND group,IL-1β and TNF-α were increased in obese rats in juvenile and adult(P<0.05 or 0.01).IL-1β and TNF-α were decreased in the HB group than that in adult obese rats(all P<0.01).5.BBR ameliorated bone biomechanical injury in adult obese male SD ratsCompared with the ND group,the maximum load,maximum fracture load,stiffness,energy absorption,ultimate tensile strength were decreased(P<0.01 or 0.05)in adult obese rats.The maximum load,maximum fracture load,stiffness,energy absorption were significantly enhanced(P<0.01 or P<0.05)in the HB group compared with obese rats.Ultimate tensile strength and elastic modulus were improved,but there was no significant difference between the HB group and obese rats(all P>0.05).6.BBR improved bone microstructure damage in adult obese male SD ratsCompared with the ND group,the trabecular volume bone mineral density(Tb.vBMD),trabecular bone volume/total volume(Tb.BV/TV),trabecular number(Tb.N)and trabecular thickness(Tb.Th)were significantly decreased(all P<0.01),and the trabecular separation(Tb.Sp)and structure model index(SMI)were increased(all P<0.01)in obese SD rats.Tb.vBMD,Tb.BV/TV,Tb.N,Tb.Sp,SMI were improved,but no significant differences were found(P>0.05)in the HB group compared to obese rats.The cortical volume bone mineral density(Ct.vBMD),cortical bone volume/total volume(Ct.BV/TV)and cortical bone thickness(Ct.Th)had no significant differences among three groups(all P>0.05).The results of HE staining in the left tibia samples showed that the trabecular number was decreased in obese rats compared with the ND group(P<0.01).Conclusions:1.The body weight and total fat percentage of male SD rats fed with HFD in 12 week were significantly increased.The inflammatory indexes of obese rats were significantly higher than those of control group.Abnormal glucose tolerlance and low insulin sensitivity exsit in obese male SD rats.2.Trabecular bone injury has occurred in juvenile obese male SD rats,but the bone strength had no significant change.In adult obese rats,the bone resorption marker increased significantly,and the trabecular bone injury further aggravated,and bone strength parameters were declined.3.BBR improved glucose metabolism and insulin resistance in obese male SD rats,improve inflammatory makers,reduced triglyceride ester in liver and the number of bone marrow adipocytes.4.BBR increased bone formation marker P1NP,reduced bone resorption marker CTX-1,and improved bone microstructure and bone strength parameters,especially in bone strength parameters.更多还原