Piezo1离子通道介导的流体剪切应力抑制MLO-Y4骨细胞凋亡

目的:研究Piezo1机械敏感性离子通道对骨细胞的调控作用。方法:应用课题组研发的流体剪切力（FSS）加载装置,使用免疫荧光探究FSS对Piezo1通道在MLO-Y4中影响的最佳强度;对Piezo1使用FSS、激动剂Yoda1或阻滞剂GsMTx4进行干预。使用Western Blot探究Cleaved Caspase-3、Bcl-2、Bax凋亡相关蛋白的表达量;使用Hoechst-33258以及流式细胞凋亡检测MLO-Y4骨细胞的凋亡比例。结果:免疫荧光染色结果表明FSS对MLO-Y4骨细胞中Piezo1的表达呈现先增加后降低的单峰趋势,其中以9 dyne/cm2加载30 min为最佳刺激条件。使用Yoda1抑制MLO-Y4细胞凋亡（P<0.05）,使用GsMTx4促进MLO-Y4细胞凋亡（P<0.05）。Piezo1介导的FSS抑制MLO-Y4细胞凋亡（P<0.05）。结论:Piezo1机械敏感性离子通道介导的FSS在9 dyne/cm2条件下抑制MLO-Y4骨细胞凋亡,且FSS在该条件下可以有效逆转Piezo1阻滞剂GsMTx4在4 μmol/L作用0.5 h下促进MLO-Y4细胞凋亡作用。     

Normal bone physiology,remodelling and its hormonal regulation

Bone is a complex tissue, which has a number of mechanical and physiological functions. The maintenance and repair of bone is ensured by a constant cycle of turnover and remodelling. The control of this process is equally complex and is regulated by both mechanical and biological controls.     

激素性股骨头坏死模型中凋亡相关因子的表达

背景：近年研究发现,激素性股骨头坏死模型中存在大量凋亡骨细胞,而Caspase-3 及Bcl-2 为调节细胞凋亡的两个重要因子。 目的：观察Bcl-2和Caspase-3在激素性股骨头坏死大鼠模型中的表达及二者的相关性。 方法：选取健康Wistar大鼠60只随机分为2组,实验组臀肌注射泼尼松龙12.5 mg/kg,每周2次,制备激素性股骨头坏死模型;对照组注射等量生理盐水。分别于给药后4,8,12周获取离体大鼠股骨头,采用苏木精-伊红染色观察骨组织形态学改变,免疫组织化学染色观察Bcl-2和Caspase-3蛋白的表达水平,并采用直线相关分析Bcl-2和Caspase-3的相关性。 结果与结论：对照组及实验组股骨头外形均完整,软骨面平整、光滑。随着给药时间的延长,实验组大鼠股骨头内骨小梁逐渐变细,脂肪细胞增多,骨陷窝空虚率明显升高。免疫组织化学染色显示：与对照组比较,实验组大鼠股骨头Caspase-3表达明显增高(P < 0.01),且随给药时间的延长呈逐渐增高趋势;而Bcl-2的表达显著低于对照组(P < 0.01)。相关分析结果显示Bcl-2和Caspase-3在各组内的表达不具有相关性。提示激素可提高Caspase-3的表达促进骨细胞凋亡,降低Bcl-2的表达抑制抗凋亡作用,进而导致激素性股骨头坏死的发生和发展。     

Bone Cell Viability After Irradiation: An enzyme histochemical study

Adult rabbits were irradiated to one proximal tibial metaphysis while the contralateral tibia served as a control. Each animal was thus its own control. Single doses of 15, 25 and 40 Gy ⁶⁰Co were used. The follow-up time was 11 to 22 weeks after irradiation. A histochemical method, recording diaphorase (NADH₂ and NADPH₂) activity in osteocytes, was employed. This method is regarded as superior to conventional histology. No evidence of osteocyte death was found even after 22 weeks following 40 Gy irradiation. This is interpreted as an indication that the osteocytes, which are end stage cells, are relatively radioresistant.     

构建及鉴定人生存素基因的慢病毒表达载体

背景：抑制椎间盘细胞的凋亡可以延缓椎间盘的退变,而生存素具有调节细胞增殖和抗凋亡功能。目的：构建人生存素基因的慢病毒载体。方法：应用全基因合成技术合成人生存素基因（BIRC5）,通过 PCR扩增目的基因并对 PCR 结果进行电泳分析。将目的基因克隆到慢病毒表达质粒构建重组慢病毒质粒 Lenti-BIRC5。将重组的慢病毒质粒转化细菌感受态细胞,PCR鉴定阳性的克隆进行基因测序。将含有目的基因的慢病毒质粒转染293T细胞,应用Western blot技术对重组慢病毒载体 Flag-Survivin 融合蛋白的表达进行检测。结果与结论：PCR鉴定及基因测序结果显示成功构建了含有人Survivin基因的慢病毒表达载体,Western blot检测结果显示目的基因在体外培养细胞中转染成功并且过表达。说明慢病毒表达载体Lenti-BIRC5构建成功,这为下一步研究Survivin在人髓核细胞中的抗凋亡作用提供了载体。     

Parathyroid hormone (PTH)–induced bone gain is blunted in SOST overexpressing and deficient mice

Intermittent parathyroid hormone (PTH) treatment is a potent bone anabolic principle that suppresses expression of the bone formation inhibitor Sost. We addressed the relevance of Sost suppression for PTH‐induced bone anabolism in vivo using mice with altered Sost gene dosage. Six‐month‐old Sost overexpressing and 2‐month‐old Sost deficient male mice and their wild‐type littermates were subjected to daily injections of 100 µg/kg PTH(1–34) or vehicle for a 2‐month period. A follow‐up study was performed in Sost deficient mice using 40 and 80 µg/kg PTH(1–34). Animals were sacrificed 4 hours after the final PTH administration and Sost expression in long bone diaphyses was determined by qPCR. Bone changes were analyzed in vivo in the distal femur metaphysis by pQCT and ex vivo in the tibia and lumbar spine by DXA. Detailed ex vivo analyses of the femur were performed by pQCT, µCT, and histomorphometry. Overexpression of Sost resulted in osteopenia and Sost deletion in high bone mass. As shown before, PTH suppressed Sost in wild‐type mice. PTH treatment induced substantial increases in bone mineral density, content, and cortical thickness and in aging wild‐type mice also led to cancellous bone gain owing to amplified bone formation rates. PTH‐induced bone gain was blunted at all doses and skeletal sites in Sost overexpressing and deficient mice owing to attenuated bone formation rates, whereas bone resorption was not different from that in PTH‐treated wild‐type controls. These data suggest that suppression of the bone formation inhibitor Sost by intermittent PTH treatment contributes to PTH bone anabolism. © 2010 American Society for Bone and Mineral Research     

Relationship between osteocyte apoptosis and orbital bone development in rabbits

Orbitalboneactsasanimportantcomponentoforbit ,whichnotonlyprotectstheorbitalcontentsfrominjurybutalsomaintainscountenancenormal.Nowadaysthemechanismoforbitaldevel opmentisuncertain .Cellapoptosisisaselectionprocessofphysiologicalcellde letion .Itsexecutio…