PI3 K/Akt信号通路在骨质疏松病理过程中的作用

磷脂酰肌醇三激酶/蛋白激酶B( PI3K/Akt)信号通路是调节细胞增殖、分化、存活、迁移和代谢过程的最为重要的一个信号通路。越来越多的证据表明,骨组织中的许多信号分子能够选择性激活PI3K/ Akt信号通路的相关基因,通过调控成骨细胞和破骨细胞的活动,破坏骨重建过程中骨形成与骨吸收的动态平衡,在骨质疏松的发生和发展中扮演着非常重要的角色。     

益生菌制剂通过PI3K/Akt信号通路改善骨质疏松大鼠的骨代谢和骨量

摘要：目的 从磷脂酰肌醇3激酶/丝氨酸-苏氨酸激酶（PI3K/AKT）通路,观察肠道菌群调节剂-益生菌制剂对骨代谢及骨量的影响,为益生菌治疗骨质疏松症（osteoporosis,OP）提供可靠资料。方法 建立肠道菌群失调性OP大鼠模型,并设置为正常对照组、模型组、益生菌制剂组、PI3K/AKT通路激活剂组、益生菌制剂+通路激活剂组,每组15只。给药干预治疗14 d后,检测粪便含水量及菌群分布;通过ELISA法检测血清炎症因子及骨生物学指标变化、骨密度仪检测骨密度、灰化法检测骨灰重、HE及抗酒石酸酸性磷酸酶（TRACP）染色观察骨病理损伤及破骨细胞骨吸收数目、Western blot法检测PI3K/Akt通路相关蛋白表达。结果 与正常对照组相比,模型组大鼠肠道菌群失衡,血清炎症因子升高,骨代谢异常（促骨形成因子减少,β-CTX及RANKL等破骨活性降低）,PI3K/Akt通路活性升高（P<0.05）。益生菌制剂可纠正肠道菌群失衡,抑制血清炎症因子释放、改善OP大鼠骨代谢失衡,并抑制PI3K/Akt通路活性（P<0.05）。PI3K/Akt通路激活剂可削弱益生菌制剂的上述作用,加重骨代谢失衡及肠道菌群失调（P<0.05）。结论 益生菌制剂干预治疗,可减弱菌群失调并纠正OP大鼠的骨代谢异常,且其作用可能与抑制PI3K/Akt通路激活有关。     

釉丛蛋白1表达对结直肠腺癌细胞增殖、凋亡及PI3K/AKT信号通路的影响

目的:探究釉丛蛋白1(TUFT1)表达对结直肠腺癌细胞(HCT-15)增殖、凋亡及磷脂酰肌醇3-激酶/蛋白激酶B(PI3K/Akt)信号通路的影响。方法:2019年3月至2021年5月,20例结直肠癌(CRA)患者癌组织及相应癌旁组织。将HCT-15细胞分为对照组、siRNA-NC组、siRNA-TUFT1组、siRNA-TUFT1+IGF-1(PI3K/Akt通路激活剂25 ng/mL)组;实时荧光定量PCR检测组织及细胞中TUFT1表达;CCK-8法、克隆形成实验检测细胞增殖;流式细胞仪检测细胞周期及凋亡情况;Western blot检测组织及细胞中增殖、凋亡及PI3K/Akt通路相关蛋白表达情况。结果:与癌组织相比,癌旁组织中TUFT1 mRNA及蛋白表达显著增加(P<0.05);与对照组相比,siRNA-TUFT1组细胞增殖抑制率、G0/G1期细胞、细胞凋亡率、Caspase-3、Bax表达水平显著增加,而c-Myc、Cyclin D1表达水平、克隆细胞数、S期和G2/M期细胞、p-PI3K/PI3K、p-Akt/Akt水平显著降低(P<0.05);IGF-1可逆转TUFT1沉默对上述指标的影响。结论:TUFT1表达沉默可能通过抑制PI3K/Akt通路激活来抑制HCT-15细胞增殖、促进凋亡。     

黄芪多糖通过PI3K/AKT/mTOR促进激素性骨质疏松症大鼠成骨细胞增殖

目的 探讨黄芪多糖在体内外通过PI3K/AKT/mTOR信号通路对糖皮质激素诱导的骨质疏松症（glucocorticoid-induced osteoporosis,GIOP）的保护作用。方法 从分化的骨髓间充质干细胞（bone marrow mesenchymal stem cells,BM-MSCs）中培养成骨细胞,分为PBS组、模型组、LY294002组、黄芪多糖组和LY294002+黄芪多糖干预组。通过CCK-8法和碱性磷酸酶（alkaline phosphatase,ALP）染色检测细胞增殖和分化。MDC染色观察自噬体的形成。Western blot检测Beclin-1、p62等信号通路及自噬相关因子的蛋白表达。大鼠分为对照组、模型组、LY294002组、黄芪多糖组和LY294002+黄芪多糖组。比较各组大鼠的骨密度、骨组织形态学参数、组织中通路和自噬相关因子的表达。结果 黄芪多糖促进成骨细胞的增殖和分化能力（P＜0.05）。与模型组相比,黄芪多糖组PI3K/AKT/mTOR通路相关磷酸化蛋白的表达、成骨细胞的增殖分化能力、自噬体及自噬相关因子的表达均升高,但在LY294002组中发现了相反的结果（P＜0.05）。在体内实验中,与模型组相比,GIOP大鼠通过黄芪多糖干预改善了骨密度和骨形态参数,并提高了软骨组织中自噬相关因子的表达,而LY294002干预则表现出相反的结果（P＜0.05）。LY294002部分逆转了黄芪多糖对GIOP中成骨分化和骨形态参数的影响。结论 黄芪多糖通过PI3K/AKT/mTOR通路对GIOP发挥保护作用,可能与诱导自噬和促进成骨细胞增殖有关。     

PI3K/AKT通路与骨质疏松症的关系及中医药干预的研究进展

骨质疏松症是一种由多种信号通路共同介导和影响的临床骨科常见的代谢性疾病,因其并发症常严重影响患者正常生活质量,并造成较大的经济损失而被广泛研究及报道。中医药治疗方案与PI3K/AKT通路因其能直接或间接影响骨骼组成细胞中的成骨细胞与破骨细胞共同介导的"骨平衡",在骨质疏松症治疗中产生显著效果而被越来越多学者深入的研究。近年来,大量动物实验及分子研究分析指出,中医药治疗方案、PI3K/AKT通路与骨质疏松症之间具有较大的相关性,国内外学者也对中医药手段直接或间接激活PI3K/AKT通路治疗骨质疏松症的相关机制进行了多维度、深层次的研究。虽然目前对于中医药治疗方案、PI3K/AKT通路与骨质疏松症之间的相关性研究不断深入,但在其分子机制研究等方面仍存在欠缺。本文将通过对中医药治疗方案、PI3K/AKT通路与骨质疏松症的相关性研究进行综述,旨在为中医药干预骨质疏松症提供新的思路。     

二甲双胍调控PI3K/Akt/mTOR通路减轻糖皮质激素诱导的成骨细胞凋亡

目的探讨二甲双胍(Met)调控磷脂酰肌醇3激酶(PI3K)/蛋白激酶B(Akt)/哺乳动物雷帕霉素靶蛋白(m TOR)信号通路对糖皮质激素地塞米松(Dex)诱导的成骨细胞凋亡的影响。方法将体外培养的小鼠胚胎成骨细胞前体细胞MC3T3-E1分为对照组(正常培养)、Dex组(以Dex处理)、Met组(以Dex和Met共同处理)、Met+IGF-1组(以Dex、Met和PI3K/Akt/m TOR通路活化剂IGF-1共同处理)、Met+NVP-BEZ235组(以Dex、Met和PI3K/Akt/m TOR通路抑制剂NVP-BEZ235共同处理),采用免疫印迹法(WB)检测MC3T3-E1细胞中PI3K、Akt、磷酸化(p)-Akt、m TOR和p-mTOR蛋白表达水平,通过噻唑蓝(MTT)法检测MC3T3-E1细胞存活率、流式细胞术检测MC3T3-E1细胞凋亡率、实时荧光定量PCR检测MC3T3-E1细胞中Bcl-2和Bax mRNA表达水平、Caspase-3活性测定试剂盒检测MC3T3-E1细胞Caspase-3活性、JC-1探针检测MC3T3-E1细胞线粒体膜电位变化。结果与对照组比较,Dex组细胞中PI3K、p-Akt、p-mTOR蛋白表达水平和细胞存活率、Bcl-2 mRNA表达水平以及线粒体膜电位均明显降低,而细胞凋亡率、Bax mRNA表达水平和Caspase-3活性均明显升高(P0.05);与Dex组比较,Met组细胞中PI3K、p-Akt、p-mTOR蛋白表达水平和细胞存活率、Bcl-2 mRNA表达水平以及线粒体膜电位均明显升高,而细胞凋亡率、Bax mRNA表达水平、Caspase-3活性明显降低(P0.05);给予IGF-1作用后Met对MC3T3-E1细胞的作用效果明显增强,而给予NVP-BEZ235作用后Met对MC3T3-E1细胞的作用效果明显减弱(P0.05)。结论 Met可通过激活PI3K/Akt/m TOR通路抑制线粒体凋亡途径,减轻糖皮质激素Dex诱导的成骨细胞凋亡。     

GH/IGF-1与骨质疏松的研究进展

骨质疏松症是由多种原因引起的一种系统性疾病,其机制极其复杂。生长激素(GH)和胰岛素样生长因子1(IGF-1)在骨的代谢过程中作用显著,其体内水平的变化与骨量及骨密度的维持密切相关。GH/IGF-1对于治疗骨质疏松有潜在的应用价值及广阔前景。本文就GH/IGF-1与骨质疏松的关系及相应作用机制作一综述。     

红景天苷激活PI3K/AKT通路改善绝经后骨质疏松症实验研究

目的探讨红景天苷激活PI3K/AKT通路改善绝经后骨质疏松症的作用。方法建立绝经后骨质疏松症大鼠模型,随机分为模型组、LY294002(PI3K/Akt通路抑制剂)组、红景天苷组、红景天苷+LY294002组,每组12只,另取12只设为假手术组。分组处理后,通过骨科生物力学测试仪测定大鼠股骨生物力学指标弹性模量、最大载荷、屈服载荷;测定大鼠股骨骨矿盐含量;运用苏木精-伊红(HE)染色检测各组大鼠骨组织病理变化;通过酶联免疫吸附法(ELISA)检测血清白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)水平;运用蛋白免疫印迹法检测脑组织PI3K/Akt通路相关蛋白表达情况。结果与假手术组相比,模型组大鼠骨组织呈现骨小梁稀疏断裂、数目明显减少,有较多空隙、不能连接成网等病理损伤,血清IL-6及TNF-α水平均显著升高(P0.05),股骨弹性模量、最大载荷、屈服载荷、骨矿盐含量、骨组织p-PI3K/PI3K、p-Akt/Akt水平均显著降低(P0.05);与模型组相比,红景天苷组大鼠骨组织病理损伤减轻,血清IL-6及TNF-α水平降低(P0.05),股骨弹性模量、最大载荷、屈服载荷、骨矿盐含量、骨组织p-PI3K/PI3K、p-Akt/Akt水平升高(P0.05); LY294002组大鼠骨组织病理损伤加重,血清IL-6及TNF-α水平升高(P0.05),股骨弹性模量、最大载荷、屈服载荷、骨矿盐含量、骨组织p-PI3K/PI3K、p-Akt/Akt水平降低(P0.05)。与LY294002组相比,红景天苷+LY294002组大鼠骨组织病理损伤减轻,血清IL-6及TNF-α水平降低(P0.05),股骨弹性模量、最大载荷、屈服载荷、骨矿盐含量、骨组织p-PI3K/PI3K、p-Akt/Akt水平升高(P0.05)。与红景天苷组相比,红景天苷+LY294002组大鼠骨组织病理损伤加重,血清IL-6及TNF-α水平升高(P0.05),股骨弹性模量、最大载荷、屈服载荷、骨矿盐含量、骨组织p-PI3K/PI3K、p-Akt/Akt水平降低(P0.05)。结论红景天苷可能通过激活PI3K/Akt通路改善绝经后骨质疏松症。     

Hedgehog信号通路与骨质疏松症

Hedgehog信号通路是一条保守而重要的信号通路,涉及到多种细胞的增殖和分化活动。近年研究发现,Hedgehog信号通路可以通过上调Runx2和Osx等主要转录因子的表达促进间充质干细胞（mesenchymalstemcells,MSCs）向成骨细胞分化,并且抑制MSCs向脂肪细胞分化。Hedgehog信号通路还可以通过调节细胞周期蛋白促进成骨细胞增殖。本文综述总结了Hedgehog信号通路调节成骨细胞增殖分化的作用机制,认为Hedgehog信号通路通过促进成骨细胞增殖分化参与调节骨代谢,为骨质疏松症的治疗提供一种新思路。     

Rspo1通过Wnt/β-catenin信号通路调节成骨细胞分化的研究进展

在成骨细胞的分化增殖中,经典Wnt /β-catenin通路起着重要的调节作用;此通路中的任何一个因子都能影响成骨细胞的分化增殖。近几年里,大量研究证明R-脊椎蛋白家族巳成为Wnt/β-catenin信号通路的重要调节因子。本文就Rspo1通过Wnt/β-catenin信号通路调控影响成骨细胞分化增殖的研究进展作一综述。     

Comparison of the haemodynamic actions of desflurane/N2O and isoflurane/N2O anaesthesia in vascular surgical patients

Background: The purpose of this study was to compare heart rate and arterial blood pressure response to desflurane/N₂O vs isoflurane/N₂O anaesthesia in a randomised clinical trial performed in patients before vascular surgery.
Methods: To evaluate associated changes in the autonomic nervous system with maintenance of anaesthesia, we used power spectral analysis (PSA) of heart rate and blood pressure and measured plasma catecholamine concentrations. Twenty-five patients whose trachea had been intubated after propofol induction were given either desflurane or isoflurane at 1 and 1.5 MAC in N₂O (60%) in a random manner.
Results: At an anaesthetic depth of up to 1.5 MAC, arterial blood pressure, indices of sympathetic activity derived from PSA, decreased with both anaesthetics, while heart rate and plasma catecholamine concentrations did not significantly change. Plasma renin activity significantly increased at 1.5 MAC anaesthesia in both groups.
Conclusions: We conclude that sympathetic hyperactivity previously reported during desflurane anaesthesia in healthy volunteers is not frequent in clinical practice in elderly vascular surgical patients under desflurane/N₂O anaesthesia, since it occurs at an anaesthetic depth which cannot be reached in these patients because of the lowering arterial blood pressure effects of desflurane, which are similar to those of isoflurane.     

Principles of CO2/Erbium Laser Safety

BACKGROUND: There are a variety of potential hazards with laser technology. METHODS: A review of the literature. OBJECTIVE: To summarize the potential hazards of CO2 and erbium laser technologies and the safety guidelines and equipment developed to minimize them. RESULTS: Laser hazards can be divided into the following categories: mechanical, environmental, macrobiologic, microbiologic, and iatrogenic. CONCLUSION: At the conclusion of this learning activity, the reader should be able to discuss the mechanical, environmental, macrobiologic, microbiologic, and iatrogenic hazards of resurfacing laser technology, the literature cited to support current safety guidelines, and the equipment developed to promote laser safety.     

Clinical relevance of the B12/N2O interaction A report of a seminar

The interaction of nitrous oxide and vitamin B₁₂ and its implications are not the exclusive territory of any one discipline. The initial discovery was by a chemist but it is of obvious relevance to anaesthetists and intensivists; some complications are neurological others haematological. The interaction provides an extremely important research tool as the first easily available B₁₂-deficient animal model. Finally there are implications for exposure to contaminated atmospheres in hospitals and in industry.     

Acute Xenograft Rejection Mediated by Antibodies Produced Independently of TH1/TH2 Cytokine Profiles

There is substantial support for the hypothesis that T(H)1 cytokine responses are critical for the normal elaboration of allograft rejection. Recent studies by Wang et al. (1) underscore the importance of T(H)2 responses in xenograft rejection and revealed that T(H)1 cytokines, IL-12 and interferon-gamma (IFN-gamma), can negatively regulate the development of humoral responses necessary for xenograft rejection. Their exceptional studies prompted us to test whether the ability of allografts to elicit cellular rejection and xenografts to induce humoral rejection also result from the differential ability to induce T(H)1 and T(H)2 responses. We compared the kinetics of antibody and cytokine (IFN-gamma and IL-4) production in C57BL/6 mice following allograft transplantation with BALB/c hearts and in C57BL/6 and BALB/c mice following transplantation with Lewis rat hearts. We also compared the ability of BALB/c mice, deficient in the ability to produce IL-4 or IFN-gamma, to reject xenografts and produce xenoantibodies. We observed that T(H)1/T(H)2 cytokine production minimally affected the kinetics of graft rejection but regulated the magnitude of IgG subclass production. Anti-graft IgM played a critical role in initiating acute antibody-mediated xenograft rejection, and the production antigraft IgM was unaffected by IL-4 or IFN-gamma deficiency. In contrast to the report by Wang et al. (1), we conclude that antibody-mediated xenograft rejection in the concordant Lewis rat heart-to-C57BL/6 mouse xenotransplantation model is dependent on anti-IgM production but independent of T(H) cytokine profiles.