间歇性低氧大鼠肺内TLR4的表达及影响

目的 通过慢性歇性低氧造成大鼠阻塞性睡眠呼吸暂停(OSA)的模型,检测TLR4在肺内的表达,探讨TLR4的表达水平对肺部炎症及其他可能发生的病变的影响。方法 将SPF级健康雄性Wistar大鼠32只采用数字表法随机分为4组(每组8只),分别为A组(常氧组)、B组(轻度低氧组,即氧浓度为15%)、C组(中度低氧组,即氧浓度为9%)和D组(重度低氧组,即氧浓度为6%)。造模35天后,取肺组织于光镜下观察大鼠肺组织形态学变化,免疫组化检测TLR4在各组大鼠肺组织中的表达水平。结果 A组肺组织未见明显异常,B、C、D这3组肺泡间隔增厚,淋巴细胞浸润,部分伴有肺气肿改变,随缺氧程度增加肺泡破坏程度加重。免疫组化结果显示,A组中无TLR4表达,B、C、D这3组TLR4呈梯度表达,D组TLR4表达最明显,差异有统计学意义(P=0.000)。结论 慢性间歇性低氧可以造成大鼠肺组织的病理损伤和炎症,且随着缺氧程度的增加,肺组织的病理损伤更严重,TLR4表达更多。     

间歇性低氧动物模型的建立及验证

目的研制间歇性低氧(intermittent hypoxia,IH)氧舱,建立IH动物模型并进行验证,为深入开展阻塞性睡眠呼吸暂停低通气综合征(OSAHS)机制的研究提供实验平台。方法采用隔离密封的结构和电气控制技术,研制均匀混合各种气体浓度的氧舱,调整实验参数,建立3个IH大鼠模型:90s 10%模型组(A组)、60s 10%模型组(B组)、60s 5%模型组(C组)同时加入空气模拟对照组(D组),实验利用A、B、C、D 4组大鼠,造模前后测量体温和呼吸次数,造模后2h行血气分析,记录5个时间点的PO2(P1、P2、P3、P4、P5)和SaO2(S1、S2、S3、S4、S5),分析结果并对3个模型进行评价。结果模型组造模后呼吸较造模前加快(P<0.05),体温无明显变化。在一个低氧-复氧周期内,同一模型组的PO2、SaO2有明显波动,S3及P3与其他时间点的PO2、SaO2比较明显下降(P<0.05)。与D组比较,各模型组P3及S3降低(P<0.05);与A组比较,B组P3及S3升高(P<0.05),C组P3及S3降低(P<0.05)。结论本IH氧舱模型操作简便、控制精确、重复性佳,60s 10%、90s 10%、60s 5%模式分别模拟轻度、中重度、重度OSAHS,符合疾病的病理生理特点,是研究OSAHS睡眠呼吸暂停—慢性间歇低氧模式的理想动物模型。     

慢性间歇性低氧对大鼠胸主动脉内皮细胞的影响

目的 探讨慢性间歇性低氧对大鼠胸主动脉内皮细胞的损伤变化。方法 将12只10～12周龄的雄性SD大鼠采用抽签法分为对照组和实验组,每组各6只。实验组大鼠每天10点至18点置于间歇性低氧环境中暴露,对照组大鼠不做低氧处理,共4周。饲养时间结束后取大鼠胸主动脉标本行苏木精-伊红染色（hematoxylin and eosin staining,HE染色）及原位末端转移酶标记法（terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay,TUNEL）染色观察细胞病变情况,并计算病变细胞、凋亡细胞在视野中所占比例。结果 HE染色光镜下实验组可见血管内皮细胞肥大,排列不规则,细胞核、胞质着色淡,平滑肌细胞核肿胀;对照组见血管内皮细胞和平滑肌细胞排列规则、细胞核形态及染色正常。TUNEL染色光镜下实验组可见多个凋亡细胞,对照组偶见凋亡细胞。实验组大鼠主动脉组织的细胞病变率及凋亡率均显著高于对照组（P<0.01）。结论 阻塞性睡眠呼吸暂停低通气综合征所产生的慢性间歇性低氧可损伤大鼠胸主动脉...     

内质网应激诱导慢性间歇低氧幼鼠认知相关的脑损害

目的 探讨内质网应激对慢性间歇低氧幼鼠脑损害的机制。方法 取SPF级健康雄性SD幼鼠32只,随机分为4组：间歇低氧（IH）2、4周组（2IH,4IH组）,对照2、4周组（2C,4C组）,每组8只。采用八臂迷宫测试各组幼鼠工作记忆错误（WME）、参考记忆错误（RME）、总错误数（TE）,观察海马神经元凋亡变化,测定免疫球蛋白结合蛋白（BiP）、转录激活因子4（ATF4）、C/EBP同源蛋白（CHOP）和磷酸化RNA激活蛋白激酶的内质网类似激酶（p-PERK）的表达水平。结果 慢性间歇低氧导致幼鼠学习记忆能力下降,与2周组比较,4周组明显（WME：3.38±0.52 vs 2.12±0.84;RME：4.25±0.71 vs 3.00±0.93;TE：7.62±0.74 vs 5.12±0.64,P均<0.01）;IH组海马神经元发生凋亡,4周组最明显（20.78%±2.63% vs 14.94%±1.59%,P<0.01）。IH组幼鼠海马BiP、ATF4和CHOP mRNA表达均增加,4IH组ATF4、CHOP mRNA表达显著升高（ATF4：3.50±0.24 vs 1.92±0.13,P<0.01;CHOP：3.09±0.22 vs 1.95±0.18,P<0.01）。2IH、4IH组p-PERK、CHOP蛋白表达上调,4IH组表达明显升高（p-PERK 3.72±0.21 vs 1.85±0.07,P<0.01;CHOP：4.29±0.27 vs 2.69±0.11,P<0.01）。结论 慢性间歇低氧可上调记忆相关脑区BiP、CHOP、ATF4 mRNA和p-PERK、CHOP蛋白的表达,表明内质网应激诱导慢性间歇低氧幼鼠认知相关的脑损害;PERK/ATF4/CHOP信号通路可能是内质网应激的分子机制。     

机体和细胞对间歇性低氧的反应与呼吸暂停综合征的关系

 睡眠障碍伴反复性呼吸暂停的患者表现为交感神经活动（sympathetic nerve activity,SNA）增强的自主神经系统功能失调和高血压。动物实验表明反复呼吸暂停引起的慢性间歇性低氧(chronic intermittent hypoxia,CIH)是激发自主神经系统功能失调的主要因素。在啮齿类动物模型中,CIH使动脉化学感受性反射功能增强的部分原因在于增加了颈动脉体对低氧的敏感性,因而导致SNA增强。最近研究表明,缺氧诱导因子-1和2(hyproxia-inducible factor,HIF)转录的变化及随之而来的活性氧类介导的信号,是CIH时化学感受性反射引起的交感神经系统兴奋的重要细胞机制。     

牛磺熊脱氧胆酸对棕榈酸诱导的INS-1细胞凋亡的保护作用

目的:探讨牛磺熊脱氧胆酸(tauroursodeoxycholic acid,TUDCA)对棕榈酸(palmitate)诱导的INS-1细胞凋亡的保护作用?方法:分别用不同浓度棕榈酸(0.25?0.50?1.00 mmol/L)?棕榈酸(0.50 mmol/L)加TUDCA(100 μmol/L)培养INS-1细胞24 h,用四甲基偶氮唑盐(MTT)法检测细胞活性,流式细胞术检测细胞早期凋亡,Western blot检测内质网应激相关蛋白GRP78的表达?结果:与对照组相比,棕榈酸组(浓度≥0.5 mmol/L)的INS-1细胞凋亡率显著上升(P < 0.05);加TUDCA培养24 h以后,与棕榈酸组相比,INS-1细胞凋亡率显著下降(P < 0.05)?此外,棕榈酸组(0.5 mmol/L)INS-1细胞内质网应激相关蛋白GRP78的表达显著上升(P < 0.05);加TUDCA培养24 h以后,与棕榈酸组相比,INS-1细胞GRP78蛋白表达显著下降(P < 0.05)?结论:TUDCA能够减少游离脂肪酸引起的INS-l细胞凋亡,对INS-1细胞发挥保护作用?而减少内质网应激蛋白的表达,缓解内质网应激可能是其作用机制之一?     

慢性间歇性缺氧大鼠模型的初步研究

目的通过慢性间歇性缺氧大鼠模型的建立,研究OSAHS的自身病理、病理生理变化和并发症的发病机理。方法选取16只SD成年雄性大鼠,随机分为空白组(unhandledcontrolgroup,UC)和慢性间歇性缺氧组(chronicintermittenthypoxiagroup,CIH),UC组正常饲养,CIH组每日间歇缺氧7h,实验期间每周测量血压1次,8周结束实验,所有大鼠在实验结束后进行Morris水迷宫测试,检测学习和记忆能力,取大鼠脑、心、肺、肾及血管分别进行病理检测。结果大鼠心、脑、肺、肾、血管组织均出现明显缺氧改变;CIH大鼠收缩压逐渐升高,从第2周开始显著升高,第2,3,4周时其收缩压分别升高了13.75mmHg(P<0.01),22.25mmH(gP<0.01)和29.87mmH(gP<0.01)。实验后两组大鼠之间比较,第1周收缩压差异无显著,第2周后CIH大鼠较UC大鼠收缩压明显升高(P<0.05);Morris水迷宫学习成绩(定位航行实验):第5天训练结束时,CIH组大鼠逃避潜伏期明显长于UC组,两组之间差异有统计学意义(P<0.05);Morris水迷宫记忆成绩:实验组的穿越平台次数([3.56±1.32)次]较正常组显著减少([6.28±1.82),P<0.01];实验组在跨越目标象限时间占整个游泳的时间百分率(20.52±3.41)也较正常组显著减少([39.89±5.63),P<0.01]。结论本实验慢性间歇低氧大鼠模型可满足OSAS基础研究的需要。     

间歇性低氧大鼠氧化应激状态与胰岛素抵抗的相关实验研究及吡格列酮干预作用

目的：探讨吡格列酮对间歇性低氧大鼠氧化应激与胰岛素抵抗的干预作用。方法：建立OS-AHS模型,将SD雄性大鼠36只随机分为常氧对照组、模型组、吡格列酮干预组,每组12只。干预组给予吡格列酮10ml·kg-1·d-1灌胃,模型、对照组均予等量生理盐水灌胃。于实验8周终点处死大鼠,硫代巴比妥酸法、酶联免疫吸附法、比色法、蛋白免疫印迹等方法观察各组大鼠血清TNF-α、MDA、GsH-Px、H（JMA-IR及胰腺组织NF-KB蛋白的表达情况。结果：与对照组比较,模型、干预组大鼠血清TNF-α、MDA、FBG、FlNS、HOMA-IR及胰腺组织NF-KB蛋白表达均升高,GSH-Px水平降低（P〈O．05）;与模型组比较,干预组血清TNF-α、MDA、FBG、FINS、HOMA-IR及胰腺组织NF-KB蛋白表达均降低,GSH-Px水平升高（P〈0．05）。结论：吡格列酮可通过抑制NF-κB核转位降低慢性间歇行低氧氧化应激水平,改善胰岛素抵抗状态。     

阻塞性睡眠呼吸暂停综合征认知功能障碍的研究进展

阻塞性睡眠呼吸暂停综合征(OSAS)会导致慢性睡眠分裂及间歇性低氧血症,进而引起认知功能障碍,特别是注意力、执行功能、记忆等方面。其导致患者认知功能障碍的机制主要包括睡眠结构改变、间歇性缺氧、分子生物学改变。而不同的治疗方案对OSAS患者认知功能障碍的改善情况不尽相同,其中持续气道正压通气在认知功能障碍方面的改善较其他方案有明显优势,患者认知功能可得到部分逆转,但结果并不完全令人满意。目前,OSAS所致认知功能障碍的分子机制尚不明确,进一步进行分子生物学研究有助于明确病因,从而发现新的治疗方案对临床早期干预具有重大意义。     

慢性间歇性缺氧合并肥胖通过内质网应激导致小鼠肾脏损伤

目的探讨慢性间歇性缺氧合并肥胖导致小鼠肾脏损伤的作用机制。方法将C57BL/6小鼠随机分为正常对照组(RC组)、慢性间歇性缺氧组(RH组)、肥胖组(HC组)和慢性间歇性缺氧合并肥胖组(HH组)。血清肌酐、尿素氮试剂盒检测各组小鼠肾功能,HE染色观察肾脏形态,TUNEL染色观察肾小管上皮细胞凋亡,实时荧光定量PCR及Western blotting检测肾脏组织中内质网应激凋亡通路mRNA及蛋白表达。结果与RC组比较,RH组、HC组、HH组小鼠血清肌酐、尿素氮水平均升高,肾脏形态结构均紊乱,其中HH组最显著(P＜0.05)。与RC组比较,HH组凋亡细胞增多,内质网应激凋亡因子(肌醇需求酶1α、剪切后的X盒结合蛋白1、C/EBP同源蛋白、c-Jun氨基端激酶、cleaved-Caspase-3)mRNA或蛋白表达明显上调(P＜0.05)。结论慢性间歇性缺氧合并肥胖可能通过内质网应激凋亡途径诱导肾小管细胞凋亡,加重肾脏损伤。     

The effect of oxidative stress in myocardial cell injury in mice exposed to chronic intermittent hypoxia

Background Obstructive sleep apnea syndrome （OSAS） is an important risk factor for cardiovascular diseases. Chronic intermittent hypoxia （CIH） is considered to be one of the most important causes of cardiovascular diseases in OSA patients. This repeated hypoxia and reoxygenation cycle is similar to hypoxia-reperfusion injury, which initiates oxidative stress. In this study, we observed cardiocytes injury induced by CIH and the effect of N-acetylcysteine （NAC）. Methods Thirty ICR mice were randomly assigned to 3 groups： control, CIH and NAC （CIH＋NAC） groups. Malondialdehyde （MDA） and superoxide dismutase （SOD） of cardiocyte homogenates were measured. Serum lipids were measured by an instrument method. Serum cardiac troponin I （cTnl） was detected by enzyme-linked immunosorbent assays （ELISA）. Myocardium pathological sections were observed. Results （1） The SOD activity and MDA concentration of cardiocyte homogenates in the CIH group were significantly higher than in other groups （P 〈0.005）. The MDA concentration of the NAC group was lower than that of the control group （P 〈0.01）. （2） The serum cTnl concentration of the CIH and NAC groups was significantly higher than that of the control group （P 〈0.01）. （3） Serum triglyceride levels in the NAC group were lower than in the other groups （P 〈0.01）, while there were no significant differences in low density lipoprotein and high density lipoprotein among the three groups. （4） The degeneration of myocardium, transverse striation blurred, and fabric effusion were observed in tissue sections in the CIH and NAC groups. However, normal tissue was found in the control group. Conclusion The oxidative stress induced by CIH can injure cardiocytes and the injury effect can be partially inhibited by NAC.     

N-乙酰半胱氨酸在慢性间歇缺氧小鼠心肌损伤中的作用研究

目的:通过建立慢性间歇缺氧(CIH)模拟阻塞件睡眠呼吸暂停(OSAS)的动物模型,观察CIH对心脏的损伤及其可能的作用机制.方法:ICR鼠33只随机分成3组:慢性间歇缺氧组、N-乙酰半胱氨酸干预组、对照组.硫代巴比妥酸(TBA)法和黄嘌呤氧化酶法分别检测3组实验鼠心肌匀浆中丙二醛(MDA)、超氧化物歧化酶(SOD)在N-乙酰半胱氨酸干预前后的变化.酶联免疫法检测3组鼠血清中心肌肌钙蛋白Ⅰ(cTnI)水平.结果:①慢性间歇缺氧组SOD活性及MDA水平高于对照绀和N-乙酰半胱氨酸干预组(P<0.05),N-乙酰半胱氨酸干预组MDA水平低于对照组(P<0.01);②慢性间歇缺氧组及N-乙酰半胱氨酸干预组cTnI均高于对照组(P<0.01):③组织病理切片结果表明慢性间歇缺氧组及N-乙酰半胱氨酸干预组心肌组织变性,横纹模糊.伴有纤维性渗出物.而对照组正常.结论:OSAS通过氧化应激产生的过量活性氧造成心肌损伤,给予N-乙酰半胱氨酸干预后可部分抑制这种损伤.     

Changes in genioglossus and their association with serum adiponectin levels in rats subjected to chronic intermittent hypoxia

Background The genioglossus （GG） is involved in the maintenance of an open airway for effective breathing.Although the pathogenesis of obstructive sleep apnea hypopnea syndrome （OSAHS） was closely associated with GG dysfunction,its causes and possible treatment have not been elucidated.The aim of the study was to investigate the effects of chronic intermittent hypoxia （CIH） on serum adiponectin levels, electromyograph （EMG） activity and ultrastructure of GG, as well as the effect of an adiponectin supplement in anesthetized rats.Methods Forty-two healthy male Wistar rats were randomly divided into normal control （A）, CIH （B） and adiponectin treatment （C） groups, 14 rats in each group.CIH was performed eight hours per day for five weeks in both groups B and C.Group C received transvenous injection of adiponectin at the dosage of 10 μg per injection, twice a week for five weeks.At the end of the 5th week the GG EMG voltage was measured and compared among the three groups.Transmission electron microscope was used to observe the ultrastructure of the GG.Results CIH caused significant hypoadiponectinemia, weakened activity of GG EMG at both baseline and hypoxia stimulation, and induced ultrastructural pathological changes, such as, myofibril discontinuities, lysis of myofilament,edema of mitochondria and disruption of cristae, vacuolus and lysis of some mitochondria.Venous supplement of adiponectin improved the above pathological changes resulting from CIH.Conclusion CIH resulted in pathological changes in GG＇s EMG and ultrastructure, which could be improved by supplement of adiponectin and be associated with hypoadiponectinemia caused by ClH.     

Adiponectin alleviates contractile dysfunction of genioglossus in rats exposed to chronic intermittent hypoxia

Background Genioglossal dysfuntion takes an important role in pathogenesis of obstructive sleep apnea hypopnea syndrome (OSAHS) in which chronic intermittent hypoxia (CIH) is the major pathological ori...     

慢性间歇低氧大鼠模型的建立和超声心动图评价

目的 使用程序低氧舱建立慢性间歇低氧(chronic intermittent hypoxia,CIH)大鼠模型,超声心动图评价大鼠心脏结构和功能改变.方法 16只大鼠随机分为2组,每组8只,分别为CIH组和对照组.CIH组大鼠置于程序低氧舱内,按程序设计予以每天8h,共35天的间歇低氧,每一低氧-复氧循环时间为1 m...     

Hippocampal impairments are associated with intermittent hypoxia of obstructive sleep apnea

Obstructive sleep apnea (OSA), which is the most common sleep-related breathing disorder, is characterized as frequent upper airway collapse and obstruction. It is a treatable disorder but if left untreated is associated with complications in several organ systems. The health risk to OSA patients shows a strong association with acute cardiovascular events, and with chronic conditions. To the central nervous system, OSA causes behavioral and neuropsychologic deficits including daytime sleepiness, depression, impaired memory, mood disorders, cognition deficiencies, language comprehension and expression deficiencies, all of which are compatible with impaired hippocampal function. Furthermore, there exists a significant correlation between disease severity and cognitive deficits in OSA. Children with severe OSA have significantly lower intelligence quotient (IQ) and executive control functions compared to normal children matched for age, gender and ethnicity. This corroborates the findings of several pediatric studies of cognition in childhood OSA, where deficits are reported in general intelligence and some measures of executive function. In studies of OSA, it is difficult to differentiate the effects of its two main pathologic traits, intermittent hypoxia (IH) and sleep fragmentation. Many OSA studies, utilize IH as the only exposure factor in OSA studies. These approaches simplify research process and attain most of the academic goals. IH, continuous hypoxia and intermittent continuous hypoxia can all result in decreases in arterial O₂. There are striking differences to them in the response of physiological systems. There are multiple studies showing that IH treatment in a rodent model of OSA can impair performance of standard water maze tests associated with deficits in spatial learning and memory which most likely are hippocampal-dependent. Cellular damage to the hippocampal cornuammonis 1 (CA1) region likely contributes to neuropsychological impairment among OSA patients, since neural circuits in the hippocampus are important in learning and memory. In this article, studies of hippocampal impairments from IH are reviewed for elucidating the mechanisms and relationships between hippocampal impairments and IH of OSA.

     

内质网应激在眼科疾病中的研究进展

内质网是一种负责蛋白质合成、折叠以及转运,脂类生物合成,空泡运输以及胞内钙存储的多功能细胞器。内质网腔内未折叠蛋白质的蓄积及钙离子稳态的打破,诱发内质网应激,发生具有保护性的未折叠蛋白反应。内质网应激与多个信号通路相互联系,参与炎症、凋亡的发生发展,近年来得到越来越多的关注。本文就内质网应激发生机制及相关的眼科疾病的研究进展作一综述。