软骨细胞凋亡与PI3K/Akt途径及相关信号分子的研究进展

骨性关节炎(osteoarthritis,OA)是指关节面软骨发生原发性或继发性退变及结构紊乱,伴随软骨下骨质增生、软骨剥脱,从而使关节逐渐破坏、畸形,最终发生关节功能障碍的一种退行性疾病.     

PI3K/Akt signaling regulates epithelial-mesenchymal transition of peritoneal mesothelial cells in peritoneal dialysis

Objective To investigate the role of PI3K/Akt signaling in the regulation of epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) in peritoneal dialysis in vitro and in vivo. Methods The level of Phosphorylated serine/threonine kinase Akt and the expression of EMT associated gene and protein, including ZO-1, Vimentin and FN, were measured in mice EMT model. In vitro study, phosphorylation level and nuclear translocation of Akt, ZO - 1 and Vimentin expression induced by TGF - β1 in human peritoneal mesothelial cells (HPMCs) were also observed. Moreover, HPMCs were pre-treated by one of PI3K/Akt inhibitor, LY294002, or transfected with dominant-negative Akt plasmid to inhibit PI3K/Akt signaling, then analyzed its effect on Zo-1 and Vimentin expression induced by TGF-β1. Results Compared with the control, thickened parietal peritoneum and remarkable decrease in mRNA and protein of the epithelial marker ZO-1, and notable increased in the expression of mesenchymal markers Vimentin and FN were observed in PD mice (all P＜0.01). Moreover, the phosphorylation of Akt also significantly increased under above condition (P＜ 0.01). In vitro study, with the stimulation of TGF-β1, the expression of Zo-1 was down-regulated, while the expression of Vimentin increased (all P＜0.01). In addition, TGF-β1 remarkably increased pAkt in HPMCs (all P＜0.01) in dose-dependent. However, LY294002 and DN-Akt dramatically inhibited the vimentin expression in HPMCs induced by TGF-β1 after inhibition of pAkt. On the other hand, the expression of ZO - 1 also was restored (P＜0.01). Conclusion PI3K/Akt signaling is involved in EMT of peritoneal mesothelial cells in peritoneal dialysis, and may be a new target for the prevention and treatment of peritoneal fibrosis during PD.     

软骨细胞凋亡与PI3K/Akt途径及相关信号分子的研究进展

骨性关节炎（osteoarthritis,OA）是指关节面软骨发生原发性或继发性退变及结构紊乱,伴随软骨下骨质增生、软骨剥脱,从而使关节逐渐破坏、畸形,最终发生关节功能障碍的一种退行性疾病。在生理状态下,软骨细胞的分解代谢和合成代谢处于平衡状态,维持软骨细胞外基质结构和功能的完整性,而软骨细胞凋亡既可以维持这种平衡,也可以破坏这种平衡。因此,软骨细胞的凋亡作用已成为当今医学领域中的研究课题之一。软骨细胞凋亡是一种由基因控制多信号调控的、主动去除细胞的程序性死亡过程。     

血管紧张素II通过PI3K/Akt/FOXO1信号通路诱导骨骼肌细胞萎缩

目的探讨血管紧张素II(Ang II)对骨骼肌细胞的调控作用及其作用机制。方法使用Ang II及其1型受体(AT1R)拮抗剂(ARB)奥美沙坦干预C2C12成肌细胞,分为Control、Ang II和Ang II+ARB三组。使用2%马血清诱导成肌细胞分化为肌管细胞。免疫荧光染色检测肌管细胞的平均面积改变,Western blot检测肌管细胞泛素连接酶、生肌调节因子(MRFs)和PI3K/Akt/FOXO1信号通路蛋白表达的变化。结果免疫荧光染色显示,Ang II干预后,肌管细胞的平均直径和面积减小(P0.001);使用奥美沙坦干预后,肌管细胞平均直径和面积明显增大(P 0.01)。Western blot显示,Ang II干预后,肌管细胞pPI3K/PI3K(P0.01),p-Akt/Akt (P 0.001)和p-FOXO1/FOXO1 (P 0.01)的比率降低; MURF1 (P 0.05)和MAFbx (P 0.001)蛋白表达明显升高,MHC(P0.01)和MyoD(P 0.05)蛋白表达明显降低;使用奥美沙坦处理后,能够减轻Ang II对肌管细胞的干预作用。结论 Ang II能够通过抑制PI3K/Akt/FOXO1信号通路的磷酸化,促进蛋白的降解,抑制蛋白的合成,诱导骨骼肌细胞萎缩。     

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。     

PI3K/Akt信号通路在吡咯喹啉醌促雪旺细胞增殖中的作用

目的 探讨磷脂酰肌醇-3激酶/蛋白激酶B(phosphoinositide-3 kinase/Akt,PI3K/Akt)信号通路在吡咯喹啉醌促雪旺细胞增殖过程中的作用.方法 体外分离培养雪旺细胞,S-100免疫荧光鉴定;Western blot检测PI3K下游因子Akt磷酸化激活形式(p-Akt)的表达,并通过PI3K激酶抑制剂(wortmannin)阻断该通路后p-Akt的表达情况.结果 毗咯喹啉醌可使雪旺细胞发生形态学变化,加入吡咯喹啉醌后30 min即可检测到p-Akt的表达,4 h达高峰,12 h基本无表达;吡咯喹啉醌在1～100 nmol/L范围内可使p-Akt表达增加;加入wortmannin阻断PI3K后p-Akt上调表达消失(P<0.05).结论 吡咯喹啉醌可使雪旺细胞发生形态学变化,PI3K/Akt信号通路在吡咯喹啉醌促雪旺细胞增殖过程中发挥重要作用.     

肿瘤相关巨噬细胞通过PI3K/Akt途径促进胰腺癌浸润迁移的研究

目的研究PI3K/Akt信号通路对胰腺癌细胞PANC-1浸润迁移能力的影响,进一步探讨肿瘤相关巨噬细胞促进胰腺癌发生发展的分子机制。 方法通过密度梯度离心法从健康成人外周血中分离单个核细胞,用IL-4体外诱导选择性激活的巨噬细胞(M2)。采用实时荧光定量PCR和Western blotting法检测胰腺癌PANC-1细胞PI3K、Akt mRNA和蛋白表达水平的变化,利用Transwell侵袭实验与划痕实验观察细胞浸润迁移能力的变化。 结果体外模拟胰腺癌微环境,将胰腺癌PANC-1细胞与不同激活状态的巨噬细胞共培养,证明M2可显著上调胰腺癌PANC-1细胞PI3K、Akt的mRNA和蛋白水平,共培养20 h后可明显促进胰腺癌PANC-1细胞的浸润与迁移能力。 结论肿瘤相关巨噬细胞可通过PI3K/Akt信号通路促进胰腺癌细胞的浸润与迁移。     

骨髓间质干细胞通过影响PI3K/Akt信号通路抑制肝星状细胞的增殖

目的 探讨在体外非接触共培养条件下,大鼠骨髓间质干细胞(MSCs)如何调控肝星状细胞(HSCs)的增殖。方法 实验组将MSCs/HSCs按2×104/2×104(细胞/孔)的比例接种于Transwell共培养板上下层,建立非接触共培养体系;对照组为HSCs(2 ×104细胞/孔)单独培养;阳性对照组为加入抑制剂LY294002 (20 μmol/ml)观察抑制效果。共培养24、48、72h后应用流式细胞仪分析细胞周期,Western blot检测HSCs的p-Akt及Akt蛋白的表达。结果 共培养24、48、72 h后HSCs的S期细胞与对照组比较明显减少,且抑制程度呈时间依赖性(11.24±0.34 ＜15.73±0.76＜19.14±0.91 ＜23.16±1.80,P＜0.05);加入LY294002后可明显增加共培养组抑制效果,与单独使用抑制剂比较S期细胞减少更加明显(8.2±0.8＜11.7±1.6,P＜0.05);共培养组及共培养+抑制剂组p-Akt蛋白表达较单独培养组均显著下调,而Akt蛋白表达差异无统计学意义(P＞0.05);共培养+抑制剂组较共培养组p-Akt蛋白表达下调。结论 MSCs可明显抑制HSCs的增殖,可能是通过影响PI3K/Akt信号通路达到这一作用,磷酸化的Akt蛋白在其中起关键作用。     

黄连素通过PI3K/Akt/mTOR信号通路抑制高糖条件下的肾脏系膜细胞增殖

目的：探讨黄连素（berberine,BBR）对高糖条件下的大鼠肾脏系膜细胞 HBZY-1 cells （MCS）增殖的影响及其作用机制。方法将对数生长期细胞分成正常糖处理组（NG 组）,高糖组（HG组）和黄连素组（BBR组）。NG组细胞体系常规培养培养,HG 组细胞体系加入40 mmol/L 葡萄糖,BBR组细胞培养体系中加入40 mmol/L葡萄糖＋黄连素30μmol/L。各组细胞培养48 h 后,利用MTT检测各组HBZY-1细胞增殖;RT-PCR检测各组细胞p85,Akt和mTOR基因表达;West-ern blotting检测细胞中 p85、p-p85、Akt、p-Akt,mTOR 和 Collagen-Ⅳ蛋白的变化。结果 NG 组与HG组增值率分别为（25%±3%）和（75%±5%）,与 NG组增值率比较,HG组肾脏系膜细胞增殖率明显增高（P〈0.05）,p85与 Akt mRNA表达水平和蛋白水平均无明显变化（P＆gt;0.05）,但 p-p85、p-Akt,Collagen-Ⅳ蛋白表达水平和 mTOR mRNA 表达与蛋白水平均明显增加（P〈0.05）;BBR 组增值率为（42%±5%）,与 HG 组比较,BBR 组肾脏系膜细胞增值率明显降低（P〈0.05）,但 p-p85、p-Akt、Collagen-Ⅳ蛋白表达水平和 mTOR mRNA 表达与蛋白水平均明显下降（P〈0.05）,而 p85和Akt mRNA和蛋白表达水平均无统计学差异（P〈0.05）。结论黄连素能抑制高糖导致的系膜细胞增殖,其作用可能是通过抑制PI3K/Akt/mTOR信号通路激活。     

P38MAPK和P13K/Akt信号通路在大鼠糖尿病神经病理性疼痛中的交互作用

目的 观察p38MAPK和P13K/Akt信号通路在大鼠糖尿病神经病珲性疼痛中的交互作用.方法 Wistar大鼠腹腔单次注射链脲菌素65 mg/kg制作糖尿病神经病理痛模型.4周后用von frey纤维测双后足机械痛阈,痛阈明显下降为糖尿病神经病理性疼痛造模成功.将96只成模大鼠随机均分为三组:糖尿病神经病理痛组(D组),PI3K抑制药组(E组)和p38MAPK抑制药组(F组).另取同窝大鼠32只作为对照组(C组).成模后的每周周一,E组和F组大鼠分别静脉注射P13K抑制药Wortmannin 0.5 mg/kg和p38MAPK抑制药SB203580 1 mg/kg,直至处死大鼠.于给药前(T1)和给药后第2周末(T2)、第4周末(T3)、第6周末(T4)分别随机取8只大鼠,检测机械缩足反应阈值(MWT)、神经传导速度(NCV)、脊髓和背根神经节(DRG)磷酸化Akt(p-Akt)水平和磷酸化p38MAPK(p-p38MAPK)水平.结果 与C组比较,D、E和F组在T1～T4时MWT下降,NCV减慢,p-Akt和p-p38MAPK水平升高(P<0.05);与D组比较,E和F组在T2～T4时MWT升高,NCV增快,E和F组p-Akt明显下降,F组p-p38MAPK水平明显下降(P<0.05).结论 P38MAPK通过激活其下游的P13K/Akt信号通路参与了糖尿病大鼠神经病理痛的形成和维持.     

Long-term androgen-ablation causes increased resistance to PI3K/Akt pathway inhibition in prostate cancer cells

BACKGROUND: In advanced stages of prostate cancer, the phosphatidylinositol-3' kinase (PI3K)/Akt signaling cascade, one of the major survival pathways in the cell, is frequently constitutively activated due to mutation or loss of the tumor suppressor protein phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Using cell culture models representing different tumor stages, we explored the effect of inhibition of this survival pathway on the induction of apoptosis. METHODS: Inhibition of the survival kinase Akt and induction of apoptosis was analyzed in androgen-insensitive DU145 and PC-3 cells, in androgen-responsive LNCaP, and in androgen-independent long-term androgen-ablated LNCaP-abl cells representing therapy-resistant prostate cancer cells. Activated Akt was determined by immunoblotting using a phospho-Akt specific antibody. Induction of apoptosis was analyzed employing annexing V and propidium iodide staining and flow cytometry and measurement of cleavage of the caspases substrate poly-ADP-ribose polymerase (PARP). RESULTS: IGF-1, EGF, and heregulin but not PDGF or activators of protein kinase A induced phosphorylation of Akt in DU145 cells and activation was completely blocked by the PI3K inhibitor LY294002. In the hormone-responsive prostate cancer cell line LNCaP that has a constitutively switched-on Akt kinase, LY294002 caused a dose- and time-dependent Akt inhibition, which was absent in long-term androgen-ablated LNCaP sublines. In agreement with the resistance to inhibition of the PI3K/Akt pathway, long-term androgen-ablated LNCaP sublines remained relatively resistant to induction of cell death by LY294002 or the cytotoxic drug etoposide. Inhibition of the PI3K/Akt pathway restored the sensitivity of long-term androgen-ablated cells to induction of apoptosis by a cytotoxic drug almost completely. CONCLUSION: These results suggest that long-term androgen ablation therapy for prostate cancer reinforces the PI3K/Akt pathway and impedes its inhibition thus contributing to increased resistance of tumor cells to induction of apoptosis. With regard to treatment of therapy-refractory prostate cancer, these findings suggest effectiveness of a combination of cytotoxic treatment and inhibition of the PI3K-Akt survival pathway in tumor cells after failure of androgen-ablation therapy.     

miR-155靶向调节PIK3R1对类风湿关节炎大鼠模型PI3K/Akt/mTOR信号通路的影响

目的 探讨miR-155靶向调节PIK3R1对类风湿关节炎（rheumatoid arthritis,RA）大鼠PI3K/Akt/mTOR信号通路的影响。方法 SD大鼠随机分为对照组、模型组、miR-155 agomir组、miR-155 antagomir组、miR-155阴性对照组,诱导RA模型,分组处理后,观察关节症状,检测关节炎指数及后足趾容积;HE染色观察大鼠关节组织病理形态;使用试剂盒检测大鼠关节组织炎性因子IL-6、IL-17及IL-18水平;免疫印迹检测大鼠关节组织PI3K/Akt/mTOR信号通路蛋白表达;qRT-PCR实验检测大鼠关节组织miR-155及PIK3R1 mRNA水平;双荧光素酶报告基因实验检测miR-155对PIK3R1的靶向调控作用。结果 与对照组比较,模型组大鼠关节炎症状明显,关节炎指数、后足趾容积、关节组织炎性因子IL-6、IL-17及IL-18水平、关节组织p-PI3K/PI3K、p-Akt/Akt及p-mTOR/mTOR水平、关节组织miR-155水平明显升高（P＜0.05）,PIK3R1 mRNA水平明显降低（P＜0.05）。与模型组、miR-155阴性对照组比较,miR-155 antagomir组大鼠上述指标得到明显改善（P＜0.05）;miR-155 agomir组与miR-155 antagomir组趋势相反（P＜0.05）。结论 miR-155可靶向下调PIK3R1的表达,激活PI3K/Akt/mTOR信号,加重RA大鼠关节炎症损伤,下调miR-155表达,可抑制PI3K/Akt/mTOR信号激活及炎症反应发生发展,改善关节炎症状。     

PI3K/Akt信号通路在富氢水减轻心肺转流致大鼠心肌损伤中的作用

目的 评价磷脂酰肌醇3激酶/蛋白激酶B（PI3K/Akt）信号通路在富氢水（HRS）减轻心肺转流（CPB）致大鼠心肌损伤中的作用。
方法 清洁级成年雄性SD大鼠40只,10～12周龄,体重350～400 g。采用随机数字表法分为四组：假手术组（S组）、CPB组（C组）、HRS处理组（H组）和PI3K抑制剂组（P组）,每组10只。S组仅进行血管穿刺置管,置管后通过尾静脉注射生理盐水6 ml/kg,机械通气90 min,其余各组建立无血预充心脏不停跳CPB模型,CPB 60 min。CPB前60 min,P组通过腹腔内注射PI3K抑制剂6 ml/kg（LY294002,5 μg/ml）。CPB前30 min,C组通过尾静脉注射生理盐水6 ml/kg,H组和P组通过尾静脉注射HRS 6 ml/kg。四组均于CPB停机2 h后取相应标本进行检测。采用Masson染色法观察心肌组织形态学变化;测定大鼠心肌含水量;采用ELISA法测定血浆心肌损伤标记物 [心肌肌钙蛋白I（cTnI）、乳酸脱氢酶（LDH）、肌酸激酶同工酶（CK-MB）]和炎性因子[白细胞介素-1β（IL-1β）、白细胞介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）]以及心肌组织氧化应激指标[丙二醛（MDA）、髓过氧化物酶（MPO）、氧化物歧化酶（SOD）]浓度;采用Western blot法检测心肌组织凋亡相关蛋白[B细胞淋巴瘤-2蛋白（Bcl-2）、Bcl-2相关x蛋白（Bax）、半胱氨酸天冬氨酸蛋白酶-3（caspase-3）]及PI3K信号通路相关蛋白 [PI3K、Akt、磷酸化Akt（p-Akt）、血红素加氧酶-1（HO-1）]含量。
结果 S组心肌组织结构基本正常,C组心肌纤维化且明显损伤,H组心肌纤维损伤得到改善。与H组比较较,P组大鼠心肌损伤程度较为严重。与S组比较,C组、H组和P组心肌含水量、血浆cTnI、LDH、CK-MB和IL-1β、IL-6、TNF-α浓度、心肌组织MDA、MPO浓度、Bax、caspase-3蛋白含量明显升高（P<0.05）,SOD浓度、Bcl-2和PI3K、p-Akt、HO-1蛋白含量明显降低（P<0.05）。与C组比较,H组心肌含水量、血浆cTnI、LDH、CK-MB和IL-1β、IL-6、TNF-α浓度、心肌组织MDA、MPO浓度、心肌组织Bax、caspase-3蛋白含量明显降低（P<0.05）,心肌组织SOD浓度、Bcl-2和PI3K、p-Akt、HO-1蛋白含量明显升高（P<0.05）。与H组比较,P组心肌含水量、血浆cTnI、LDH、CK-MB和IL-1β、IL-6、TNF-α浓度、心肌组织MDA、MPO浓度、心肌组织Bax、caspase-3蛋白含量明显升高（P<0.05）,心肌组织SOD浓度、心肌组织Bcl-2和PI3K、p-Akt、HO-1蛋白含量明显降低（P<0.05）。C组和P组上述指标差异无统计学意义。
结论 HRS减轻CPB致大鼠心肌损伤的机制与激活PI3K/Akt信号通路有关。     

Dual efficacy of Fasudil at improvement of survival and reinnervation of flap through RhoA/ROCK/PI3K/Akt pathway

Fasudil is reported to be effective at protecting against ischaemic diseases, and at augmenting axon growth. In this study, we aim to evaluate its efficacy in promoting flap survival and reinnervation. Ninety‐two Institute of Cancer Research (ICR) mice were used and divided into the control, Fasudil, LY294002, Fasudil+LY294002 groups, receiving a daily intraperitoneal injection of normal saline, Fasudil (10 mg/kg), LY294002 (5 mg/kg), and Fasudil (10 mg/kg) + LY294002 (5 mg/kg), respectively. On days 0 and 5, the blood perfusion and diameter of the iliolumbar artery in the pedicle of the flaps in the four groups were evaluated using laser speckling contrast imaging (LSCI). On day 5, the flaps were photographed and the necrosis rate of the flaps was calculated using Photoshop CS6. In addition, tissues were harvested from the flaps and divided into two parts. One part underwent routine cryosection and immunofluorescent staining using the antibody against CD31 for evaluation of the microvascular density in the four groups. In the other part, the expression of RhoA, ROCK1+2, p‐CPI‐17, p‐MYPT, p‐PTEN, p‐PI3K, p‐Akt, and vascular endothelial growth factor (VEGF) within the flaps were determined using western blotting. Moreover, at days 0, 7, 15, and 30 after flap surgery, the axons within the flaps were evaluated using immunofluorescent staining with the antibody against Neurofilament‐200. It turned out that the necrosis rate was (24.4 ± 7.7)%, (5.2 ± 1.6)%, (29.8 ± 4.2)%, and (30.9 ± 7.1)%, respectively, in the control, Fasudil, LY294002, LY294002+Fasudil groups. There was a significant reduction in the necrosis rate of the flaps in the Fasudil group (P < .001). The LSCI and immunofluorescent staining demonstrated that Fasudil could significantly expand the diameter of the iliolumbar artery in the pedicle, boost the overall blood perfusion, and increase the microvascular density of the flaps in the Fasudil group (P < .05), which could all be abolished by PI3K inhibitor LY294002. On day 5, the expression of p‐CPI‐17, p‐MYPT, and p‐PTEN were downregulated, whereas pPI3K, p‐Akt, and VEGF were upregulated in the Fasudil group (P < .001). As for reinnervation, Neurofilament‐200 fluorescent staining revealed that at days 15 and 30 after flap harvest, only in the Fasudil group could new axons be observed. It can be concluded that Fasudil could simultaneously improve the survival and axon growth after flap harvest, a dual efficacy achieved by inhibition of the RhoA/ROCK pathway, which in turn activates /PI3K/AKT pathway.     

受体诱导一氧化碳经PI3 K/Akt信号途径抑制冷缺血再灌注诱导的移植心细胞凋亡

目的 观察受体诱导一氧化碳(CO)对移植心冷缺血再灌注(I/R)损伤中细胞凋亡的影响,并探讨其机制.方法 以BALB/C小鼠建立同系移植心冷I/R损伤模型.受体麻醉前3 h以二氯甲烷(MC)500 mg/kg灌胃诱导CO(MC组,n=12),或橄榄油灌胃(IR组,n=12);在MC组的基础上受体在移植心恢复血供前1 h腹腔注射PI3K抑制剂LY294002(40 mg/kg,LY组,n=10)或二甲亚砜(DMSO组,n=10);检测移植后3、24 h移植心细胞凋亡指数(AI)、磷酸化Akt(p-Akt)蛋白、bcl-2与bax蛋白表达比值;设正常对照组(N组,n=5).结果 受体以MC灌胃后血液中碳氧血红蛋白(COHb)浓度与心肌组织CO含量均在3 h达到峰值,分别为(9.82±0.84)%和(2.25±0.08)pmol/mg;与IR组比较,MC组明显降低移植心AI[3 h:(8.65±2.01)%比(19.28±4.94)%,P＜0.01;24 h:(5.82±2.36)%比(10.54±3.66)%,P＜0.05]、激活Akt蛋白(3 h:P＜0.01;24 h:P＜0.05)、上调bcl-2/bax比值(3 h:1.97±0.16比0.46±0.07,P＜0.01;24 h:1.89±0.10比0.51±0.04,P＜0.01);与MC组比较,LY组明显增加AI[3 h:(17.95±4.92)%,P＜0.01;24 h:(9.75±3.14)%;P＜0.01]、抑制Akt蛋白激活(P＜0.01)、下调bcl-2/bax比值(3 h:0.47±0.06,P＜0.01;24 h:0.52±0.03,P＜0.01);DMSO组与MC组的各个指标差异无统计学意义(P＞0.05).结论 受体诱导C0能明显抑制冷I/R诱导的移植心细胞凋亡,其机制可能与通过PI3K/Akt信号途径上调bcl-2/bax比值有关.     

The role of PI3K/Akt signaling pathway in non‐physiological shear stress‐induced platelet activation

The PI3K/Akt signaling pathway has been implicated in playing an important role in platelet activation during hemostasis and thrombosis involving platelet‐matrix interaction and platelet aggregation. Its role in non‐physiological shear stress (NPSS)‐induced platelet activation relevant to high‐shear blood contacting medical devices (BCMDs) is unclear. In the context of blood cells flowing in BCMDs, platelets are subjected to NPSS (>100 Pa) with very short exposure time (<1 s). In this study, we investigated whether NPSS with short exposure time induces platelet activation through the PI3K/Akt signaling pathway. Healthy donor blood treated with or without PI3K inhibitor was subjected to NPSS (150 Pa) with short exposure time (0.5 s). Platelet activation indicated by the surface P‐selectin expression and activated glycoprotein (GP) IIb/IIIa was quantified using flow cytometry. The phosphorylation of Akt, activation of the PI3K signaling, was characterized by western blotting. Changes in adhesion behavior of NPSS‐sheared platelets on fibrinogen, collagen, and von Willebrand factor (vWF) were quantified with fluorescent microscopy by perfusing the NPSS‐sheared and PI3K inhibitor‐treated blood through fibrinogen, collagen, and vWF‐coated microcapillary tubes. The results showed that the PI3K/Akt signaling was involved with both NPSS‐induced platelet activation and platelet‐matrix interaction. NPSS‐sheared platelets exhibited exacerbated platelet adhesion on fibrinogen, but had diminished platelet adhesion on collagen and vWF. The inhibition of PI3K signaling reduced P‐selectin expression and GPIIb/IIIa activation with suppressed Akt phosphorylation and abolished NPSS‐enhanced platelet adhesion on fibrinogen in NPSS‐sheared blood. The inhibition of PI3K signaling can attenuate the adhesion of unsheared platelets (baseline) on collagen and vWF, while had no impact on adhesion of NPSS‐sheared platelets on collagen and vWF. This study confirmed the important role of PI3K/Akt signaling pathway in NPSS‐induced platelet activation. The finding of this study suggests that blocking PI3K/Akt signaling pathway could be a potential method to treat thrombosis in patients implanted with BCMDs.     

法舒地尔对糖尿病大鼠肾小管上皮细胞转分化的影响

目的 观察法舒地尔对糖尿病大鼠肾小管上皮细胞转分化的影响并探讨其机制。 方法 将实验性Wistar大鼠随机分为正常对照组、糖尿病组、法舒地尔治疗组。3个月后处死动物,PAS染色法观察肾小球病理变化,Masson染色法观察肾间质病理变化;免疫组化观察肾脏皮质ROCKⅠ、α平滑肌肌动蛋白（α-SMA）、E钙黏蛋白（E-cadherin）的变化和β连环蛋白（β-catenin)的细胞定位改变;Western印迹法观察肾脏皮质p-MYPT1、α-SMA、E-cadherin、胞膜β-catenin蛋白的变化;实时定量PCR法观察ROCKⅠ、E-cadherin和总β-catenin的mRNA变化。 结果 法舒地尔治疗可改善肾间质纤维化状况。与正常对照组相比,糖尿病组大鼠肾皮质内p-MYPT1、α-SMA蛋白表达增强（均P < 0.01）;E-cadherin、胞膜β-catenin的蛋白表达减弱（均P < 0.01）;ROCK1、总β-catenin mRNA表达增强（均P < 0.01）;E-cadherin mRNA表达减弱（P < 0.01）。与糖尿病组相比,治疗组p-MYPT1、α-SMA蛋白表达减弱 （均P < 0.01）;E-cadherin、胞膜β-catenin的蛋白表达增强（均P < 0.05）;ROCK1、β-catenin mRNA表达减弱（均P < 0.01）;E-cadherin mRNA表达增强（P < 0.01）。 结论 法舒地尔可能通过抑制Rho激酶活性减轻糖尿病大鼠肾小管上皮细胞转分化和肾间质纤维化,该作用可能与法舒地尔恢复肾小管上皮细胞的黏附特性与紧密连接复合体有关。