整合素在破骨细胞介导的骨吸收中的作用

在骨吸收的过程中,破骨细胞是唯一效应细胞。破骨细胞表面高度表达的整合素αVβ3通过与骨基质的黏附可促进破骨细胞的成熟与分化,在骨吸收过程中发挥重要作用。     

红霉素抑制人工关节磨屑诱导的骨溶解

目的 探讨红霉素（EM）防治人工关节松动的可能性。方法 采集30例人体外周血,分离单核细胞（MO）。每例标本分成6组。A组：仅MO;B组：MO＋超高分子聚乙烯微粒（UHMWPE）;C组：MO＋UHMWPE＋帕米磷酸钠（10μg／ml）;D组：MO＋UHMWPE＋EM（5pμ／ml）;E组：MO＋UHMWPE＋EM（10μg／ml）;F组：MO＋UHMWPE＋EM（25μ／ml）。培养48h后,放免法测定上清中肿瘤坏死因子（TNF）含量。结果 A、C、D、E、F组的TNF含量明显低于B组。结论 EM能有效地抑制由于UHMWPE刺激MO而分泌的TNF的量。EM的效果与帕米磷酸钠相似,能防治人工关节置换术后由微粒诱导的炎症性因子引发的骨溶解,有望成为将来防治人工关节无菌性松动的一种很有潜力的药物。     

骨髓靶向柔红霉素毫微粒的研究

采用乳液聚合法制备了柔红霉素聚氰基丙烯酸正丁酯毫微粒（１）,并对其形态,粒径分布,载药性,动物体内经时变化过程及骨髓靶向性进行了研究。结果表明１平均微粒径为７０ｎｍ,分布范围３０－２２０ｎｍ,包封率为９７．０％,载药一达５５．７％;小鼠胸脉注射相同剂量１及柔红霉素后,前者股骨内峰浓度提高到１．６２倍,ＡＵＣ提高到４．８７倍,总靶向效率从５．１７％提高到２４．１９％,表明１具骨髓靶向性。     

柔红霉素毫微粒冻干针剂的研究

目的：制备易再分散、稳定的柔红霉素聚氰基丙烯酸正丁酯毫微粒（ＤＮＲ－ＰＢＣＡ－ＮＰ）冻干针剂。方法：选用适宜支架剂制得ＤＮＲ－ＰＢＣＡ－ＮＰ冻干针剂,并评价其相关理化性质。结果：冻干前后毫微粒形态、粒径、ｐＨ、包封率及载药量均无明显变化,含水量合格,再分散性良好,制剂稳定。其临界相对湿度为７５．３３％。结论：在适宜的处方及工艺条件下制备ＤＮＲ－ＰＢＣＡ－ＮＰ冻干针剂是可行的。     

红霉素肠溶片剂的体外溶出和体内吸收比较

用微生物方法测定了同一药厂2个批号的红霉素肠溶片的体外溶出和8名健康志愿者口服的体内吸收,结果表明国内文献方法和美国药典方法测定的溶出度无统计学差异;两种肠溶片体外溶出度有明显差异,体外溶出度大的肠溶片其体内吸收和生物利用度也大。提示体外溶出试验应作为红霉素肠溶片剂的质控指标。     

挤出造粒、气流包衣法制备包衣微粒剂Ⅳ.红霉素肠溶胶囊的研究

介绍了挤出、滚圆、气流包衣法制备红霉素肠溶微粒胶囊。该胶囊剂耐酸性好，人工肠液中释药快，在8名健康志愿者体内的AUC为市售红霉素肠溶片的1．99倍，且个体差异小。     

经胃肠道上皮吸收的微粒给药系统研究概况

本文综述了口服微粒给药系统经胃肠道上皮,在细胞摄粒和细胞旁路运输等的作用下,转运到集合淋巴结等肠系淋巴组织,进入全身循环的生理及实验基础。文章讨论其吸收的途径和机理,分析影响吸收、分布的因素及粒子的摄取过程及动力学特征,进而说明口服给药的微粒给药系统潜在的应用价值。     

经胃肠道上皮吸收的微粒给药系统研究概况

本文综述了口服微粒给药系统经胃肠道上皮 ,在细胞摄粒和细胞旁路运输等的作用下 ,转运到集合淋巴结等肠系淋巴组织 ,进入全身循环的生理及实验基础。文章讨论其吸收的途径和机理 ,分析影响吸收、分布的因素及粒子的摄取过程及动力学特征 ,进而说明口服给药的微粒给药系统潜在的应用价值。     

调节骨吸收相关基因的研究进展

骨吸收是维持骨重建动态平衡过程的重要环节,受到许多基因的共同调控,研究调节骨吸收的相关基因及其作用,将为骨质疏松、骨缺损修复等治疗提供更先进、更肯定的手段和方式.调节骨吸收的相关基因主要有分泌性磷蛋白,肿瘤坏死因子11,血管内皮生长因子,胰岛淀粉样多肽,5磷酸肌醇,离子通道7型P2X受体,肿瘤坏死因子受体11 b等.一些以基因组为背景,能够在整体水平上研究基因相互作用的新技术不断产生,对骨吸收相关基因的研究也将不断的深入和完善,为骨发育机制的研究、骨疾病的治疗奠定基础.     

镁硅玉微粒对骨溶解作用的实验研究

目的观察镁硅玉人工髋关节的磨损颗粒在动物体内的生物反应,比较镁硅玉和高分子聚乙烯微粒诱导骨溶解的活性,探讨镁硅玉人工髋关节松动的原因。方法昆明小鼠30只,于小鼠背部皮下注射过滤后的空气3ml,2d后再次注射1ml,air-pouch动物模型构建成功6d后,按注射微粒的不同随机分为3组,每组10只。甲组注射高分子聚乙烯微粒;乙组注射镁硅玉微粒;丙组(对照组)注射生理盐水。分别向air-pouch内注射各种微粒悬液3ml(1×108/ml),7d后处死动物,取囊壁组织,一半光镜观察,另一半制成组织匀浆。离心后取上清液,ELISA法测定IL-1β和TNF-α的含量。结果光镜下实验组可见大量吞噬细胞,而对照组未见明显组织细胞反应。实验组IL-1β的含量均高于对照组(P<0.001),且甲组高于乙组(P<0.001)。TNF-α的含量实验组和对照组、甲组和乙组均无统计学差异(P>0.05)。结论两种微粒均能引起组织学反应,诱导产生炎性细胞因子IL-1β。虽然镁硅玉微粒的生物活性较高分子聚乙烯微粒更低,但根据本实验结果,我们认为镁硅玉磨损微粒也是造成假体无菌性松动的原因之一。     

Inhibiting wear particles-induced osteolysis with doxycycline

Aim： To study the effect of doxycycline （DOX） on osteoclastogenesis, mature osteoclast fate and function, wear particles-induced osteoeolysis, and to provide some foundation for treating aseptic loosening and osteolysis after joint arthroplasty. Methods： Osteoclasts were generated from mouse bone marrow monocytes with the receptor activator of NF-κB ligand and the macrophage colony stimulating factor. DOX at a concentration of 5, 10, 15, and 20 μg/mL was respectively added to the medium. Seven days later, the osteoclasts were determined through tartrate-resistant acid phosphatase （TRAP） staining. Mature osteoclasts were isolated from newborn rabbits and cultured for 3 d in 24-well plates or on bone slices. DOX at a concentration of 5, 10, 15, and 20 μg/mL was respectively added to the medium. After TRAP staining, the osteoclasts were counted, resorption on bone slices was quantified, and the area was calculated after toluidine blue and Mayer-hematoxylin staining. Polymethyl methacrylate （PMMA） or ultra-high molecular weight polyethylene （UHMWPE） particles were implanted on the calvariae of C57BL/J6 mice. DOX, at a dose of 2 and 10 mg·kg^-1·d^-1, was respectively given intraperitoneally for 7 d. Seven days later, the calvariae were removed and processed for pathological analysis. Results： DOX treatment effectively inhibited in vitro osteoclastogenesis, affected the fate of mature osteoclasts, and inhibited mature osteoclasts, causing bone resorption. In vivo data indicated that DOX strongly inhibited PMMA or UHMWPE-induced osteolysis and osteoclastogenesis. Conclusion： DOX can effectively inhibit osteoclastogenesis and affect mature osteoclast fate and suppress wear particles induced by osteolysis and osteoclastogenesis. DOX might be useful in the treatment or prevention of wear particles-induced osteolysis and aseptic loosening for its effect on osteoclast generation and mature osteodast fate and function.     

GDF8 inhibits bone formation and promotes bone resorption in mice

Growth Differentiation Factor 8 (GDF8), also called myostatin, is a member of the transforming growth factor (TGF)‐β super‐family. As a negative regulator of skeletal muscle growth, GDF8 is also associated with bone metabolism. However, the function of GDF8 in bone metabolism is not fully understood. Our study aimed to investigate the role of GDF8 in bone metabolism, both in vitro and in vivo. Our results showed that GDF8 had a negative regulatory effect on primary mouse osteoblasts, and promoted receptor activator of nuclear factor κB ligand (RANKL)‐induced osteoclastogenesis in vitro. Intraperitoneal injection of recombinant GDF8 repressed bone formation and accelerated bone resorption in mice. Furthermore, treatment of aged mice with a GDF8 neutralizing antibody stimulated new bone formation and prevented bone resorption. Thus, our study showed that GDF8 plays a significant regulatory role in bone formation and bone resorption, thus providing a potential therapeutic pathway for osteoporosis.     

Alpha-difluoromethylornithine inhibits bone resorption in vitro without decreasing beta-glucuronidase release

Our previous studies suggested that the ornithine decarboxylase inhibitor alpha-difluoromethylornithine (DFMO) inhibits bone resorption by mechanisms that are independent of polyamine depletion. To determine whether DFMO prevents calcitriol-stimulated bone resorption by acting at a step before or after osteoclast activation, we compared the effects of DFMO on release of calcium and beta-glucuronidase from cultured neonatal mouse calvaria. DFMO, at concentrations of 7.5-20 mM, inhibited release of calcium from calcitriol-stimulated calvaria but failed to inhibit the calcitriol-stimulated increase in beta-glucuronidase secretion. In contrast, ornithine, putrescine, spermidine, and spermine, at concentrations with effects on resorption comparable to those of DFMO, inhibited the effects of calcitriol on both calcium and beta-glucuronidase release. NaF (0.2 mM), like DFMO, inhibited calcitriol-stimulated calcium release without affecting medium beta-glucuronidase activity, whereas elevated phosphate (3 mM) inhibited both activities. The results suggest that DFMO, over the concentration range studied, inhibits calcium release by making the matrix resistant to resorption rather than by acting at a cellular locus.     

Atropine inhibits bone resorption induced by high dose of zinc in rats

A single oral administration of high amounts of zinc (Zn) induced hypocalcemia and bone resorption in rats. Atropine inhibited both effects thus supporting the hypothesis that the effect of Zn administration on bone results from the hypocalcemia mediated by acetylcholine.     

Flufenamic acid inhibits osteoclast formation and bone resorption and act against estrogen-dependent bone loss in mice

Postmenopausal osteoporosis is one of the most common types of osteoporosis resulting from estrogen deficiency in elderly women. Nonsteroidal anti-inflammatory drugs (NSAIDs) are important drugs for pain relief in patients with osteoporosis. In this study, we report for the first time that flufenamic acid, a clinically approved and widely used NSAID, not only has analgesic properties but also shows a significant effect in terms of preventing postmenopausal osteoporosis. Quantitative RT-PCR analysis showed that treatment with flufenamic acid significantly downregulated the genes associated with osteoclast differentiation. Meanwhile, RNA-sequencing and western blot analyses suggested that flufenamic acid could inhibit the bone resorption by suppressing the phosphorylation of MAPK pathways. Moreover, an ovariectomy (OVX)-induced bone-loss mouse model indicated that flufenamic acid might be a potent drug for preventing osteoporotic fractures, as verified by micro-CT scanning and histological analysis. Therefore, this study proposes an attractive and potent drug with analgesic properties for the prevention of postmenopausal osteoporosis.     

Genistein prevents bone resorption diseases by inhibiting bone resorption and stimulating bone formation

Genistein, a soybean-derived isoflavone, has been shown to suppress osteoclastic bone resorption. To clarify the mechanisms underlying this action, we investigated the effects of genistein on the differentiation, cytoskeleton and function in mice osteoclasts in vitro and bone metabolism in ovariectomized rats. Study design: Primary OCs were isolated from 3 week-old mice and induced by 1,25(OH)(2)D(3). Then OCs were exposed to genistein at various concentration of 0 M, 10(-9) M, 10(-8) M, 10(-7) M, 10(-6) M, and 10(-5) M. The number of TRAP+ cells were counted as well as the surface area of bone resorption on bone slice. F-actin change was observed by Confocal. In vivo, forty 12 week-old female SD rats were randomly assigned to four groups: (1) sham operated (Sham); (2) (OVX); (3) ovariectomized and treated with estradiol (OVX-E); (4) ovariectomized and received genistein (OVX-G). After 12 weeks, BMD, body weight, serum level of alkaline phosphatase (ALP), acid phosphatase (ACP), osteocalcin (OC), IL-1beta, TNFalpha, IL-6 and calcitonin (CT) were evaluated. Femur were sectioned. In addition, the serum estradiol, the weight of uteri and histological behavior were also examined to indicate the side effect of genistein to the uteri. Results: In vitro, the number of TRAP+ cells decreased depending on the concentration of genistein as well as the area of bone resorption. F-actin became disorder under Confocal. In vivo, after treated with genistein, BMD and the serum level of ALP, ACP, osteocalcin increased significantly, while the serum level of IL-1beta and TNFalpha decreased. Especially, the increase of ALP and osteocalcin of OVX-G was higher than that of OVX-E. Histologically, the pachy-trabecula were observed as well as the more mineral deposition lines. Additionally, the uterus weight index and the serum estradiol in OVX-G rats were lower significantly than those of OVX-E. The epithelia of uteri gland in OVX-G appeared cubic while those of OVX-E became squamous. Conclusions: Genistein can prevent bone resorption diseases by the promotion of bone formation and the prevention of bone resorption with slight side effect.     

Stimulative effects of cadmium on bone resorption in neonatal parietal bone resorption.

Effects of cadmium on bone resorption were investigated using neonatal mouse parietal bone culture system. Cadmium at 0.5 microM and above stimulated hydroxyproline release as well as 45Ca release. As cadmium-stimulated bone resorption was inhibited by calcitonin, bone resorption induced by cadmium is osteoclast-mediated bone resorption. CI-1, collagenase inhibitor, depressed cadmium-stimulated bone resorption in a dose-dependent manner. Osteoblasts are also involved in cadmium-induced bone resorption. Indomethacin-inhibited cadmium-stimulated bone resorption and cadmium-treated bones released prostaglandin E2 to a greater extent than untreated bones. Cadmium-stimulated bone resorption was shown to be dependent on the production of prostaglandin E2. 3-Isobutyl-1-methylxanthine potentiated cadmium-stimulated bone resorption and verapamil depressed it. It is possible that an increase in levels of cAMP and calcium ion in bone cells is involved in cadmium-induced bone resorption. From these results, cadmium was found to stimulate osteoclast-mediated bone resorption which is dependent on prostaglandin E2. Second messengers in cadmium-induced bone resorption may be cAMP and calcium ion.     

Zinc-induced hypocalcemia and bone resorption in rats

The changes of calcium levels in serum and in the femur were examined in rats administered oral doses of zinc sulfate (0.1, 1.0, and 10 mg Zn/100 g body weight) for 3 days. All doses of zinc caused significant decreases in calcium levels in serum and in the femoral diaphysis and epiphysis. The decrease in these femoral calcium levels was seen 1 day after administration of zinc (10 mg/100 g). Furthermore, time course studies of the effect of zinc administration showed that, at 1 hr after zinc administration, calcium levels in serum and in femoral epiphysis but not in diaphysis were significantly decreased. In thyroparathyroidectomized rats, however, no significant decrease of the epiphyseal calcium was observed by administration of zinc (10 mg Zn/100 g), but the serum calcium level was significantly lowered. Zinc administration to intact rats caused a significant increase in acid phosphatase activity in the femoral epiphysis but not in the diaphysis. This increase was clearly prevented by thyroparathyroidectomy. Accumulations of zinc in the femoral epiphysis and diaphysis after zinc administration was not significantly altered by thyroparathyroidectomy. These results suggest that zinc-induced hypocalcemia may cause bone resorption which is primarily mediated by the action of the parathyroid hormone and it is related to calcium homeostasis in rats.