羟基红花黄色素A减轻大鼠心肌细胞缺氧/复氧损伤

目的观察羟基红花黄色素A(HSYA)对乳鼠原代心肌细胞缺氧复氧(A/R)损伤的保护作用及其与磷脂酰肌醇-3-激酶/蛋白激酶B/糖原合成酶激酶3β(PI3K/Akt/GSK3β)信号通路的关系。方法分离大鼠的乳鼠心肌细胞,孵育48 h,待细胞贴壁后,分为:对照组(Con组)、缺氧复氧组(A/R组)、HSYA处理组(A/R+H组)、PI3K抑制剂(LY294002)处理组(A/R+L组)和HSYA+LY294002处理组(A/R+H+L)。测培养基上清液LDH;流式细胞仪检测凋亡率;Western blot检测Bcl-2、Bax、Akt、p-Akt(Ser473)、GSK3β和p-GSK3β(Ser9)的蛋白表达水平。结果与对照组比较,A/R后LDH释放量和凋亡率增加(P0.001),促凋亡蛋白Bax表达增加(P0.001),而抗凋亡蛋白Bcl-2、p-Akt(Ser473)、p-GSK3β(Ser9)蛋白表达减少(P0.001);HSYA处理后LDH释放量和凋亡率降低(P0.001),Bax表达减少(P0.001),而Bcl-2、p-Akt(Ser473)和p-GSK3β(Ser9)蛋白表达增加(P0.001);与A/R+H组比较,A/R+H+L组Bax表达增加(P0.001),而Bcl-2、p-Akt(Ser473)和p-GSK3β(Ser9)蛋白表达减少(P0.001)。结论 HSYA可以通过调控PI3K/Akt/GSK3β信号通路保护大鼠心肌细胞缺氧/复氧损伤。     

腺苷A2b受体激活减轻小鼠肾缺血再灌注致肺损伤

目的研究腺苷A2b受体激活对肾缺血再灌注(RIR)致肺损伤的保护作用及其机制。方法雄性C57BL/6J小鼠随机分为:对照组(C组),缺血再灌注组(I/R组),缺血再灌注+A2bR激动剂Bay606583组(I/R+Bay组,1 mg/kg Bay术前15 min腹腔注射),缺血再灌注+A2bR激动剂Bay606583+Akt抑制剂LY294002组(I/R+Bay+LY组,1 mg/kg Bay+7.5 mg/kg LY术前15 min腹腔注射)及缺血再灌注+A2bR抑制剂MRS1754组(I/R+MRS组,1 mg/kg MRS术前15 min腹腔注射)。分别取血检测肾功能(血肌酐、血尿素氮);检测肺组织A2bR mRNA表达; Western blot检测肺组织p-Akt和A2bR的蛋白表达;检测各组小鼠肺组织湿重/干重比值(W/D)以及支气管肺泡灌洗液(BALF)中蛋白、TNF-α和IL-6的浓度;观察肺组织病理变化;采取动脉血进行动脉血气分析。结果肾缺血再灌注后血肌酐、血尿素氮升高,A2bR mRNA的表达随时间降低(P0.05),且p-Akt和A2bR的蛋白表达水平显著降低(P0.05)。另外,与对照组相比,再灌注后小鼠肺组织湿重/干重比值(W/D)、肺泡灌洗液蛋白、TNF-α和IL-6浓度明显增加(P0.05),肺病理损伤评分和氧合水平明显变差(P0.05),1 mg/kg Bay606583明显减轻上述损伤并增加p-Akt的表达,然而这一作用在应用Akt抑制剂LY294002后消失。结论腺苷A2b受体激活可能通过PI3K/Akt通路减轻肾缺血再灌注后肺组织损伤并改善氧合状态。     

去甲肾上腺素和缺血预处理对大鼠缺血再灌注心肌细胞凋亡、Bcl-2、Bax蛋白表达的影响

目的:研究去甲肾上腺素预处理(NE-P)和缺血预处理(IP)对大鼠缺血再灌注(I/R)心肌细胞凋亡及相关基因Bcl-2和Bax蛋白表达的影响。方法:复制缺血再灌注损伤(IRI),采用末端标记技术(TUNEL)检测心肌细胞凋亡;应用免疫组化SABC法检测Bcl-2和Bax蛋白表达。结果:I/R组凋亡细胞较多,NE-P组及IP组凋亡细胞明显少于I/R组(P＜0.01)。在I/R组Bcl-2的表达少而Bax的表达较多,NE-P组及IP组Bcl-2的表达明显高于I/R组(P＜0.01),而Bax的表达明显低于I/R组(P＜0.01)。NE-P组与IP组各指标均无显著差异(P＞0.05)。结论:NE-P可抑制I/R诱发的心肌细胞凋亡,Bcl-2和Bax的蛋白表达在心肌凋亡的发生中起重要作用。NE-P与IP两者对心肌细胞凋亡及相关基因表达的影响的作用相近。     

PI3K/Akt和JAK2/STAT3信号转导通路在SO_2抗大鼠肢体缺血再灌注致急性肺损伤中的作用

目的:探讨PI3K/Akt和JAK2/STAT3信号转导通路在二氧化硫(SO2)抗肢体缺血再灌注(I/R)致急性肺损伤中的作用。方法:应用双大腿根部绑扎止血带复制大鼠双后肢缺血再灌注肺损伤模型。在再灌注前20 min腹腔注射Na2SO3/Na HSO3;在再灌注前1 h静脉注射Stattic或LY294002。应用TUNEL、ELISA、Western blot等方法检测细胞凋亡、细胞因子表达及相关信号通路蛋白表达的情况。结果:与对照组相比,I/R组的MDA及MPO含量、肺系数、细胞凋亡指数、细胞因子表达以及p-STAT3、p-Akt蛋白的水平均显著增高;当应用Na2SO3/Na HSO3后,上述反映肺损伤的各项指标均下降。Western blot检测结果显示I/R后,肺组织中p-STAT3和p-Akt蛋白的水平均明显增加。而应用Na2SO3/Na HSO3后,p-Akt蛋白的水平继续增加,但p-STAT3蛋白的水平却减少(P0.05)。结论:JAK2/STAT3和PI3K/Akt信号通路都参与了SO2抗肢体缺血再灌注致急性肺损伤的作用。JAK2/STAT3通路的活化,能够使I/R损伤加重;相反,PI3K/Akt信号通路的活化,可以使I/R损伤减弱。此外,JAK2/STAT3和PI3K/Akt信号通路之间存在交互作用。     

丹参酮ⅡA抑制马兜铃酸诱导HUVECs凋亡及其可能机制

目的观察丹参酮ⅡA(TSN)对马兜铃酸(AA)诱导的人脐静脉血管内皮细胞(HUVECs)凋亡的保护作用及其可能机制。方法体外培养HUVECs,设对照组、AA刺激组(AA终浓度为10 mg/L)、TSN干预组(先加入0.2、0.4和0.8 mg/L TSN,1 h后再加入AA)和LY294002预处理组(20μmol/L的PI3K抑制剂LY294002预处理30 min后,再加入TSN)。24 h后,MTT法检测细胞增殖;Hoechst33258荧光染色观察细胞形态;Annexin V-FITC/PI双荧光染色流式细胞仪检测细胞凋亡率;Western blot法检测细胞Bcl-2、Bax和磷酸化Akt(p-Akt)蛋白表达及比色法测定细胞caspase-3活性。结果与对照组相比,AA引起细胞凋亡率显著增加(P0.05),细胞Bcl-2和p-Akt表达降低(P0.05),细胞Bax表达升高(P0.05);TSN能减轻AA对细胞凋亡率及对细胞Bcl-2、Bax和p-Akt表达的作用(P0.05);PI3K抑制剂LY294002可抑制TSN的抗凋亡作用(P0.05)。结论 TSN可抑制AA诱导的HUVECs凋亡。     

心肌缺血再灌注损伤中白介素-17A诱发心肌细胞凋亡的作用机制

目的探讨心肌缺血再灌注损伤小鼠心机组织中白细胞介素-17A(IL-17A)的表达及其对心肌细胞凋亡的影响机制。方法采用结扎小鼠左冠状动脉前降支(LAD)法进行心肌缺血再灌注损伤模型构建;伊文思蓝(Evan’s blue)和2,3,5-三苯基氯化四氮唑(TTC)染色与心肌损伤标记物肌酸激酶(CK)、肌钙蛋白T(c TnT)血清含量检测小鼠心肌损伤情况;Western blot检测心肌缺血再灌注(I/R)后3 h、24 h、72 h不同时间点心肌组织IL-17A的表达水平,TUNEL染色和Caspase 3活力检测进一步反映细胞凋亡情况;原代分离培养心肌细胞,不同质量浓度(10、20、40、80 ng/ml)IL-17A处理细胞24 h,TUNEL染色检测细胞凋亡率、Western blot检测凋亡相关蛋白Caspase 3、Bax、Bcl-2及PI3K/Akt通路蛋白表达变化。结果 I/R后心肌梗死区与缺血区(I/AAR)比率显著增加(P0.05),而心肌缺血区与左心室的比率(AAR/LV)无明显变化,且心肌损伤标记物肌酸激酶(CK)、肌钙蛋白T(cTnT)血清含量也明显增加;与Sham组(假手术组)相比,I/R后3 h、24 h、72 h时间点心肌组织IL-17A表达显著增加,心肌细胞凋亡率和Caspase 3活性亦明显增加;不同浓度IL-17A能够促进原代心肌细胞凋亡,诱导Caspase 3、Bax表达,抑制Bcl-2及PI3K/Akt通路蛋白表达。结论心肌缺血再灌注损伤小鼠IL-17A明显增加,高表达的IL-17A可能通过抑制PI3K/Akt通路来诱导心肌细胞凋亡。     

p-Akt、Bid与小鼠局灶性脑缺血后处理保护作用的关系

目的 探讨p-Akt、Bid在小鼠局灶性脑缺血再灌注(I/R)及缺血后处理(IP)后的启动规律,探讨p-Akt、Bid与IP保护作用的关系。方法 将315 只雄性昆明小鼠采用线栓法建立大脑中动脉栓塞模型后,随机分成假手术组(Sham组)、缺血再灌注组(I/R组)、缺血后处理组(IP组)、缺血后处理+PI-3K抑制剂LY294002组(IP+LY组)4组,于再灌注相应时间点取材,免疫组织化学方法检测p-Akt、Bid的表达及分布情况;免疫印迹法检测皮质p-Akt、Bid蛋白表达情况。氯化三苯基四氮唑（TTC）染色测定脑梗死体积。结果 与Sham组比较,I/R组神经元胞质中可见p-Akt及Bid的表达明显上调,p-Akt表达于30min增加,1 h达高峰(P<0.05),24 h回落至基线水平,Bid表达于6 h增加,24 h达高峰(P<0.05),48~72 h有所回落;IP组各相应时间点较I/R组p-Akt表达显著增加(P<0.05),Bid表达明显降低(P<0.05)。应用PI-3K特异性阻断剂LY294002阻断PI-3K/Akt信号系统活化的同时,也抑制了IP的保护作用。p-Akt蛋白表达量与Bid免疫反应性呈负相关（r=-0.8265,P <0.05）。结论 p-Akt、Bid参与缺血后处理过程;缺血后处理可能通过PI-3K/Akt通路发挥脑保护作用;Akt可能通过死亡受体通路调控Bid的表达。     

Apelin-13通过PI3K/Akt信号通路抑制尼古丁诱导的H9c2细胞凋亡

目的:研究小分子活性肽apelin-13对尼古丁诱导的心肌细胞凋亡的作用,探讨其可能的调节机制。方法:建立尼古丁诱导的大鼠H9c2细胞凋亡模型,流式细胞术检测细胞凋亡率,Western blot法检测凋亡相关蛋白的表达。结果:(1)与正常对照组相比,尼古丁组细胞凋亡率明显增加(P0.01),凋亡相关蛋白Bax和cleaved caspase-3的表达显著上调, Bcl-2、p-Akt、p-PI3K和APJ蛋白的表达显著下调(P0.01);(2)与尼古丁组相比,apelin-13+尼古丁组细胞的凋亡率明显降低(P0.01),Bax和cleaved caspase-3的表达显著降低(P0.01), Bcl-2、p-Akt、p-PI3K和APJ蛋白的表达显著升高(P0.01);(3)与apelin-13+尼古丁组相比,apelin-13+尼古丁+PI3K/Akt抑制剂LY294002组细胞凋亡率明显增加(P0.01),Bax和cleaved caspase-3的表达显著增加(P0.01), Bcl-2、p-Akt和p-PI3K蛋白的表达显著下调(P0.01)。结论:Apelin-13通过PI3K/Akt信号通路抑制尼古丁诱导的H9c2细胞凋亡。     

吡格列酮对缺血再灌注乳鼠心肌细胞凋亡的作用

目的:研究吡格列酮对离体缺血再灌注损伤心肌细胞凋亡的影响及机制,为吡格列酮治疗心肌缺血再灌注损伤提供理论基础和实验依据.方法:体外培养Wistar乳鼠心室肌细胞,建立心肌细胞缺氧复氧模型.应用免疫荧光显色检测心肌细胞Caspase 3表达变化,免疫印迹法检测各组总Akt、 p-Akt蛋白的表达变化.结果:吡格列酮使离体培养的缺血再灌注损伤心肌细胞Caspase 3阳性细胞减少,p-Akt活性增加,这一作用可被Akt抑制剂Ly294002阻断.结论:吡格列酮激活PI3K/Akt通路,减轻离体缺血再灌注心肌细胞凋亡.     

Gas6经PI3K/Akt通路对缺氧复氧诱导 H9c2细胞凋亡的影响

目的: 观察外源性重组人生长停滞特异性蛋白6(Gas6)对缺氧复氧诱导的H9c2心肌细胞系凋亡的影响,并初步探讨其与磷脂酰肌醇3-激酶/蛋白激酶B(PI3K/Akt)通路的关系。方法: 对体外培养的H9c2细胞进行缺氧复氧(3 h/3 h),模拟大鼠心肌缺血再灌注模型,将细胞随机分为4组:正常对照组(control组)、缺氧/复氧组(A/R组)、缺氧/复氧+ Gas6预处理组(A/R+Gas6组)及缺氧/复氧+ Gas6预处理+PI3K/Akt特异性阻断剂LY294002干预组(A/R+Gas6+LY294002组)。分别采用MTT法检测心肌细胞活力,生化法检测细胞中caspase-3活性水平,Annexin V/PI 双染法及流式细胞仪检测细胞凋亡率,Western免疫印迹法检测胞内磷酸化Akt(p-Akt)蛋白含量表达情况。结果: A/R组较control组细胞活力下降,caspase-3活性、凋亡率及p-Akt水平均较control组增加(P<0.05)。但经Gas6预处理后,细胞活力及p-Akt表达水平较A/R组显著增加,caspase-3活性、凋亡率均减少(P<0.05),而Gas6的这些作用能被PI3K/Akt阻断剂抑制。结论: Gas6能减少缺氧复氧诱导的H9c2细胞凋亡,此作用机制可能是通过提高Akt磷酸化水平而激活PI3K/Akt通路实现的。     

Two residues in the hemagglutinin of A/Fujian/411/02-like influenza viruses are responsible for antigenic drift from A/Panama/2007/99

The H3N2 vaccine strain (A/Panama/2007/99) for the 2003-2004 influenza season did not antigenically match the circulating A/Fujian/411/02-like H3N2 viruses and had reduced effectiveness against influenza outbreaks. A/Wyoming/03/2003, an A/Fujian-like virus, was recommended as the vaccine strain for the 2004-2005 season. A/Wyoming differed from A/Panama by 16 amino acids in the HA1 molecule. Reverse genetics was used to determine the minimal amino acid changes that were responsible for the antigenic drift from A/Panama to A/Wyoming. After substitutions of 2 of the 16 amino acids in the HA (H155T, Q156H), the A/Panama HA variant was antigenically equivalent to A/Wyoming as determined by hemagglutination inhibition and microneutralization assays using ferret postinfection antisera. Conversely, A/Wyoming containing the His-155 and Gln-156 residues from A/Panama was antigenically equivalent to A/Panama. These results indicated that only these two HA residues specified the antigenic drift from A/Panama to A/Wyoming; other amino acid differences between these two H3N2 viruses had minimal impact on virus antigenicity but impacted virus replication efficiency in eggs.     

Midazolam/ketamine sedative combination compared with fentanyl/propofol/isoflurane anaesthesia for oocyte retrieval.

Assisted reproduction may be associated with repeated occasions of surgical intervention. Propofol, which is frequently used for induction of anaesthesia in such procedures, has been suspected of damaging oocytes. We compared in a randomized prospective design the use of general anaesthesia with fentanyl 0.017 mg/kg, propofol 2.5 mg/kg and isoflurane to that of sedation with midazolam 0.06 mg/kg and ketamine 0.75 mg/kg for transvaginal oocyte retrieval in 50 patients with no premedication. Overall, patient satisfaction was not different between the groups. Sedated patients were more arousable than anaesthetized patients during the procedure and experienced less postoperative abdominal pain at 30 min. Despite some movement in response to pain, oocyte retrieval was conveniently feasible in all sedated patients, of which none required a switch to general anaesthesia. A comparable number of oocytes was retrieved per cycle, 10.8 (+/-7.8) versus 9.6 (+/-10.9) with sedation and anaesthesia respectively. No patient recalled any pain sensation during the procedure. The rate of embryo transfers and pregnancies were not different between the two groups. We conclude that the sedative combination of midazolam and ketamine for oocyte retrieval may serve as an alternative for general anaesthesia.     

AILIM/ICOS signaling induces T-cell migration/polarization of memory/effector T-cells

AILIM/ICOS has critical roles in the regulation of T-cell differentiation and effector T-cell function in various immune responses. The counter-ligand for AILIM/ICOS, B7h, is widely expressed in not only lymphoid tissue and antigen-presenting cells, but also in fibroblast and endothelial cells in various organs. Here, we demonstrate that activated human T-cells migrate beneath TNF-alpha-treated HUVEC and display morphological polarization via AILIM/ICOS signaling. AILIM/ICOS stimulation, in the absence of antigen stimulation, also induced T-cell polarization. Importantly, AILIM/ICOS-mediated polarization was evident in CD4+CD45RO+ memory T-cells and generated Th1 cells, but not in CD4+CD45RA+ naive T-cells and generated Th2 cells. Furthermore, AILIM/ICOS signaling is involved in transendothelial migration of Th1 cells, but not Th2 cells. Our data suggest that AILIM/ICOS-B7h interactions play an important role in the endothelium in controlling the entry of memory/effector T-cells into inflamed tissues in the periphery.     

Prophylactic contraceptives for HIV/AIDS

The current pandemic of sexually transmitted human immunodeficiency virus (HIV) infection--the causative agent of acquired immunodeficiency syndrome (AIDS), has created an urgent need for a new type of contraceptive: one that is both a spermicide and a microbicide. Because most women at risk for HIV infection are of reproductive age (15-44 years), effective use of dual-function contraceptives is important to prevent HIV transmission and unintended pregnancies. In the absence of an effective prophylactic anti-HIV therapy or vaccine, new emphasis has been placed on the development of intravaginal microbicidal agents capable of reducing the transmission of HIV. Topical microbicidal spermicides would ideally provide a female-controlled method of self-protection against HIV as well as preventing pregnancy. However, several microbicides that are undergoing preclinical and human clinical trials contain detergent-type ingredients. The detergent-type spermicide, nonoxynol-9, the only recommended microbicide for protection against sexual transmission of HIV has been shown to cause lesions in vaginal and cervical epithelia leaving women more vulnerable to HIV infection. Therefore, a major challenge in microbicide research has been to design mechanism-based microbicides that are highly effective against pregnancy and HIV transmission while lacking detergent-type effects on epithelial cells and normal vaginal flora. We present an overview of current microbicide research and report on the identification and preclinical development of novel non-detergent spermicidal nucleoside and non-nucleoside inhibitors aimed at decreasing pregnancy and preventing sexual transmission of HIV.     

IVF/ET and GIFI in andrology

Improvement in both in-vitro fertilization/embryo transfer (IVF/ET)and gamete intra-Falloplan transfer (GIFT) procedures have ledto a progressive extension of their use far beyond the indicationsrepresented by tubal problems. One of the most important examplesof this is in the field of male infertility. Some researchersclaim that IVF/ET is more efficient on the basis of the ‘fertilizationevidence’, while others prefer the GWF technique, stressingthat as its results are clearly so much better that it shouldbe used in all cases.     

Morbidity in a Danish national cohort of 472 IVF/ICSI twins, 1132 non-IVF/ICSI twins and 634 IVF/ICSI singletons: health-related and social implications for the children and their families

BACKGROUND: There is a lack of knowledge on child health as well as family well-being in IVF/ICSI twins. METHODS: These data originated from questionnaires completed by mothers taking part in a national cohort study of twin and singleton births occurring in Denmark in 1997. The overall response rate was 83%. The three cohorts consisted of all IVF/ICSI twin children (n = 472), all IVF/ICSI singletons (n = 634) and all non-IVF/ICSI twin children (n = 1132) born in Denmark in 1997. RESULTS: No major differences in physical health were observed between IVF/ICSI twins and non-IVF/ICSI twins. Compared with IVF/ICSI singletons, more IVF/ICSI twins were admitted to a neonatal intensive care unit (NICU) (P < 0.01) and more had surgical interventions (P = 0.03) and special needs (P = 0.02), moreover they had poorer speech development (P < 0.01). Correspondingly, IVF/ICSI twin mothers rated their infant's general health poorer than IVF/ICSI singleton mothers did. All discrepancies between IVF/ICSI twins and singletons disappeared after stratification for birthweight except for NICU admissions and speech development. Multiple logistic regression analyses showed that both IVF/ICSI and non-IVF/ICSI twin parents experienced more marital stress [odds ratio (OR) 2.9, 95% CI 2.2-3.8] and that twins had more impact on the mother's life (OR 1.7, 95% CI 1.2-2.4) compared with singletons. Nevertheless, the only predictor of low divorce/separation risk was IVF/ICSI treatment. CONCLUSION: Our study indicates that physical health of IVF/ICSI twins is comparable with that of non-IVF/ICSI twins. However, physical health of IVF/ICSI twins is poorer and the implications for the families stronger compared with IVF/ICSI singletons.     

Association of -592C/A, -819C/T and -1082A/G interleukin-10 promoter polymorphisms with idiopathic recurrent spontaneous abortion

Increasing evidence supports a role for altered T helper 1 (Th1)-Th2 cytokine balance in idiopathic recurrent spontaneous abortion (RSA). The aim of this study was to investigate the association of the interleukin 10 (IL-10) promoter polymorphisms -592C/A, -819C/T and -1082A/G with RSA. Women (n = 350) with at least three consecutive spontaneous abortions (RSA cases) and 200 control women with at least two successful pregnancies were included. The frequency of the -819T allele [P = 0.05, odds ratio (OR) = 1.51], but not other single-nucleotide polymorphisms (SNPs), was higher among RSA patients. Complete linkage disequilibrium (LD) was seen between -592C and -819C and -1082G alleles, as well as between -592A and -819T and between -819C and -1082G alleles only among patients. Although the genotype frequencies (except for -819C/C) of the three polymorphisms were comparable between patients and controls, higher frequency of -592A/-819T/-1082A haplotype (OR = 4.01, 95% CI = 1.83-7.95) was seen in cases versus controls. Regression analysis indicated that, after adjusting for potential variables, -592C/A (OR = 3.32, 95% CI = 1.76-6.27) and -819C/T (OR = 5.06, 95% CI = 2.59-9.91) were associated with exclusively early but not exclusively late RSA, where negative association for both was noted. This supports the notion of involvement of IL-10-592C/A and -819C/T polymorphisms as inherited risk factors of idiopathic RSA.     

The response of adenomyosis to endometrial ablation/resection

Operative hysteroscopy is a relatively new technique that hassignificantly improved the diagnosis and therapy of abnormaluterine bleeding. At first, the success of operative hysteroscopyin controlling this bleeding seemed extremely high but, withlong-term follow-up, a significant failure rate became evidentrequiring a repeat hysteroscopic procedure or a hysterectomy.Deep adenomyosis is a major cause of these failures. This paperdescribes three operative ablation techniques and relates manyof their failures to deep adenomyosis. The definition and pathophysiologyof adenomyosis are also explored. The possibility of delayingthe diagnosis of endometrial cancer under an ablation scan isdiscussed. Ultimately the depth of adenomyosis seems to correlatewith the outcome of endometrial ablation or resection. Patientswithout or with only minimal endometrial penetration of <2.5mm (superficial adenomyosis) have good results from the ablation.Patients with deep endometrial penetration of >2.5 mm (deepadenomyosis) usually have persistent problems and should beoffered hysterectomy over repeat ablation. Magnetic resonanceimaging or ultrasound may be an appropriate pre-operative screeningtool to determine the depth of adenomyosis.     

Hyperbaric oxygen-stimulated proliferation and growth of osteoblasts may be mediated through the FGF-2/MEK/ERK 1/2/NF-κB and PKC/JNK pathways

We investigated whether the hyperbaric oxygen (O₂) could promote the proliferation of growth-arrested osteoblasts in vitro and the mechanisms involved in this process. Osteoblasts were exposed to different combinations of saturation and pressure of O₂ and evaluated at 3 and 7 days. Control cells were cultured under ambient O₂ and normal pressure [1 atmosphere (ATA)]; high-pressure group cells were treated with high pressure (2.5 ATA) twice daily; high-O₂ group cells were treated with a high concentration O₂ (50% O₂) twice daily; and high pressure plus high-O₂ group cells were treated with high pressure (2.5 ATA) and a high concentration O₂ (50% O₂) twice daily. Hyperbaric O₂ significantly promoted osteoblast proliferation and cell cycle progression after 3 days of treatment. Hyperbaric O₂ treatment stimulated significantly increased mRNA expression of fibroblast growth factor (FGF)-2 as well as protein expression levels of Akt, p70^S6K, phosphorylated ERK, nuclear factor (NF)-κB, protein kinase C (PKC)α, and phosphorylated c-Jun N-terminal kinase (JNK). Our findings indicate that high pressure and high O₂ saturation stimulates growth-arrested osteoblasts to proliferate. These findings suggest that the proliferative effects of hyperbaric O₂ on osteoblasts may contribute to the recruitment of osteoblasts at the fracture site. The FGF-2/MEK/ERK 1/2/Akt/p70^S6K/NF-κB and PKC/JNK pathways may be involved in mediating this process.