周围神经缺血再灌注损伤的实验研究

采用暂时阻断家兔髂总动脉起始处血流的实验模型观察不同缺血再灌注时间周围神经电生理，超微结构和自由基含量的变化。结果表明：１．缺血时间越长，再灌注损伤越重。２．在一定时间范围内，再灌注时间越长，神经传导速度、潜伏期和波幅等电生理指标及神经超微结构改变越明显，再灌注损伤越重。３．缺血后自由基含量增高（Ｐ值＞０．０５），再灌注后进一步明显增高（Ｐ值＜０．０１）。这是再灌注损伤的根本原因。４．应用氯丙嗪、当归、甘露醇后神经组织内自由基含量明显下降（Ｐ值＜０．０１）。三者均有一定自由基清除能力，可用于治疗周围神经的缺血再灌注损伤。     

手术治疗周围神经缺血再灌注损伤的电生理研究

目的：探讨周围神经缺血再灌注损伤后不同时限外膜切开手术后电生理的变化。方法：对２４只兔随机分成对照组，即刻行神经外膜切开减压组、１周后神经松解和４周后神经松解组的电生理学观察。结果：神经传导的潜伏期，传导速度和肌肉动作电位波幅，各实验组均好于对照组（Ｐ＜０．０５），其中即刻行外膜切开减压组与对照组及４周后松解组比较差异有非常显著性（Ｐ＜０．０１）。结论：周围神经缺血与再灌注损伤后如能尽快或急诊行神经外膜切开减压，可取得较好疗效。     

甘露醇和当归对周围神经再灌注损伤的保护作用

目的　研究甘露醇和当归对周围神经再灌注损伤的保护作用。方法　观察神经电生理,神经内钙,自由基含量和组织结构的变化。　结果　缺血６ 小时应用甘露醇, 当归,再灌注５ 小时后潜伏期由（３７５６ ±０２０６） ｍ ｓ 减至（ ２２１６ ±００９６） ｍ ｓ 和（ ３４７２ ±０１６６ ） ｍ ｓ , 传导速度由（１２４１８ ±１０１１）ｍ ／ｓ 增至（ ２１３２０ ±０６７６ ） ｍ ／ｓ 和（ １７１２０ ±１０３５ ） ｍ ／ｓ , 波幅 由（ １２６２ ±０２５６ ） ｍ Ｖ 增 至（７１０８ ±０４３ ９） ｍ ｖ 和（２６０４ ±０２９ ７） ｍ Ｖ , 神 经内钙 由（ ７７７９４ ±８ ２６８ ） μｇ／ｇ 减 至（ ４２１３８ ±３４８９） μｇ／ｇ 和（４００９４ ±２０８２） μｇ／ ｇ 。缺血６ 小时应用当归,甘露醇再灌３ ０ 分钟, 自由基由（３７５４５ ±４４７５） Ｙｍ ａｘ／μｇ 减至（２８００９ ±２１７６） Ｙｍ ａｘ／ μｇ 和（ １１１３６ ±１８ ０６） Ｙｍ ａｘ／ μｇ 。组织形态学的变化也说明损伤程度得到明显抑制。　结论　甘露醇和当归均可用于防治周围神经的再灌注损伤, 甘露醇的作用优于当归     

大鼠坐骨神经缺血再灌注损伤机制的探讨及丹参保护作用的实验研究

目的：研究不同缺血再灌注时间周围神经中血栓素A2（TXA2）和前列环素（PGI2）的变化及丹参对其变化的影响,探讨周围神经缺血再灌注时花生四烯酸代谢变化的损伤机制。方法：采用无损伤动脉夹暂时阻断大鼠右侧骼总动脉的大鼠周围神经缺血实验模型,放射免疫方法检测不同缺血再灌注时间及应用丹参后周围神经中血栓素B2（TXB2）含量和6-酮-前列腺素Flα（6-keto-PGF1α）含草,同时行坐骨神经病理学检查及肢体功能评估。结果：随着缺血时间的延长,鼠坐骨神经中TXA2、PGI2、T／P比值增高,再灌注后,TXA2、PGI2、T／P比值明显增高,但随后PGI2则维持在一定水平。向中药丹参能使TXA2、T／P比值明显下降,减轻缺血性神经纤维变性（IFD）,改善肢体功能。结论：周围神经缺血再灌注存在花生四烯酸代谢失衡。丹参具有防止TXA2/PGI2、平衡紊乱的作用,对周围神经缺血再灌注损伤起一定保护作用。     

活络效灵丹加味对兔肢体缺血再灌注损伤的影响

目的：探讨中药方剂活络效灵丹加味在兔肢体缺血再灌注损伤中对骨骼肌的保护作用。方法：健康成年兔32只，随机分为4组，每组8只。应用止血带环扎家兔后肢造成肢体缺血再灌注损伤模型。Ⅰ组（活络效灵丹加味预防和治疗）于造模前活络效灵丹加味灌胃5d，并于恢复血流再灌注始继续活络效灵丹加味灌胃5d；Ⅱ组（活络效灵丹加味治疗）、Ⅲ组（甘露醇治疗）及Ⅳ组（模型对照）于恢复血流再灌注始分别中药灌胃、静推20％甘露醇、蒸馏水灌胃各5d。测定肢体缺血再灌注后2d和5d血清MDA、SOD、NO、LDH的含量；制备肢体缺血再灌注后5d的骨骼肌切片，进行光镜观察并比较各组组织学变化。结果：再灌注2d及5d活络效灵丹加味预防和治疗组、活络效灵丹加味治疗组、甘露醇治疗组血清MDA、LDH值显著低于模型对照组；SOD、NO值显著高于模型对照组（P〈0．05）。光镜下活络效灵丹加味预防治疗组、活络效灵丹加味治疗组、甘露醇治疗组骨骼肌损害轻于空白对照组；活络效灵丹加味预防治疗组、活络效灵丹加味治疗组骨骼肌细胞再生现象较甘露醇治疗组、模型对照组明显，而以活络效灵丹加味预防治疗组为著。结论：活络效灵丹加味在肢体缺血再灌注损伤中对骨骼肌有保护作用且能促进骨骼肌细胞再生。     

甘露醇、当归、氯丙嗪对兔周围神经缺血再灌注损伤的保护作用──家兔坐骨神经内自由基的观察

甘露醇、当归、氯丙嗪对兔周围神经缺血再灌注损伤的保护作用──家兔坐骨神经内自由基的观察王法，黄耀添，马昕近年来，自由基（ＦｒｅｅｒａｄｉｃａｌＦＲ）在缺血再灌注损伤中的作用引起了广泛关注。为了减轻其对机体损伤作用，许多ＦＲ清除剂应时而生，并已部分应用...     

p38MAPK、MMP-2在大鼠肾缺血再灌注损伤早期的表达及影响

目的：探讨p38MAPK、MMP-2在大鼠肾缺血再灌注后早期的表达情况及其在。肾缺血再灌注损伤中的作用。方法：选择健康雄性SD大鼠48只,随机分成假手术（sham）组24只,缺血再灌注（IR）组24只,建立大鼠肾缺血再灌注损伤模型,测定各组实验大鼠血清肌酐水平的变化,应用免疫组织化学二步法检测p38MAPK、MMP-2表达的变化。结果：与sham组比较,IR组血清肌酐水平升高,缺血45分钟再灌注24小时达高峰（P〈0．01）。MMP-2蛋白在sham组呈少量散在表达或不表达,缺血45分钟再灌注6小时有少量表达,再灌注12小时、24小时及72小时呈阳性表达,以24小时达高峰（P〈0．05）;p38MAPK蛋白在sham组呈少量散在表达或不表达,缺血45分钟再灌注6小时、12小时及24小时呈阳性表达,12小时达高峰（P〈0．05）。p38MAPK、MMP-2蛋白的表达与血清肌酐水平的变化呈显著正相关。结论：肾缺血再灌注可激活p38MAPK,活化的p38MAPK可以上调MMP-2蛋白的表达,可能促进了肾缺血再灌注损伤的发生和发展。     

缺血预处理改善骨骼肌功能的研究

目的：探讨缺血预处理法改善缺血骨骼肌功能的临床价值。方法：用ＳＤ大鼠１２只，以右后肢为动物实验模型。分为缺血组（对照组，鼠６只），即缺血４小时后再灌注１小时的方法；缺血预处理组（实验组，鼠６只），缺血过程同对照组，但在缺血前预先经过２次缺血５分钟、再灌注１０分钟的处理。实验时，分别于缺血前、缺血１、４小时及再灌注１小时时，测定两组实验侧肢体腓肠肌最大肌张力的变化。实验结束后分别测量血ＭＤＡ、ＣＰＫ及大鼠右后肢９９ｍＴｃ亚甲基二磷酸计数。结果：实验组最大肌张力的变化（缺血４小时、再灌注１小时时）较对照组有明显改善；血ＭＤＡ、ＣＰＫ及肌肉９９ｍＴｃ亚甲基二磷酸较对照组显著降低。结论：缺血预处理不仅能改善骨骼肌的缺血耐受性，而且能有效地改善骨骼肌的功能     

肢体缺血再灌注后微动脉对去甲肾上腺素、乙酰胆碱及硝酸甘油反应性变化

目的 探讨肢体缺血再灌注后向血管痉挛的发生机制。方法 应用兔后肢止血带常温缺血模型及足背肌腱表面微循环观察法，观察肢体缺血２小时及５小时再灌注后微动脉对局部滴注血管滴注血管收缩剂、内皮依赖性血管舒张剂及内皮非依赖性血管舒张剂的反应性变化。结果 与缺血前比较，肢体缺血２小时再灌注后，微动脉对上述三种血管活性物质的及硝酸甘油的无显著性变化；缺血５小时再灌注后，微动脉对去甲肾上腺素的收缩反应仍无显著性变     

肢体缺血再灌流对胫前筋膜间隔压力影响的实验研究

为了观察肢体不同缺血时间再灌流后筋膜间隔的压力变化以及与血清丙二醛（ＭＤＡ）、血清肌酸液酶（ＣＰＫ）含量变化的关系,观察甘露醇对肢体缺血再灌流的保护作用,作者将１８只新西兰兔分成３组,分别观察各组术前、缺血即时、缺血期末、再灌流４、２４、７２小时筋膜间隔的压力变化以及血清ＭＤＡ、ＣＰＫ的含量变化和骨骼肌的组织学变化。结果显示：缺血时间越长,组织损伤越重,再灌流后损伤进一步加重,以再灌流２４小时到达顶点,血清ＭＤＡ、ＣＰＫ均达峰值,与筋膜间隔的压力变化一致。应用甘露醇组的变化则明显减轻。实验结果表明,肢体缺血再灌流可以导致筋膜间隔的压力增高,从而使损伤进一步加重,这种损伤以再灌流后２４小时最为严重,而甘露醇可以明显减轻组织的损伤和降低筋膜间隔的压力。     

Effect of trapidil in ischemia/reperfusion injury of peripheral nerves

OBJECTIVE: Ischemia plays an important role in the development of pathological changes in nerve tissue, and restoration of blood flow results in injury (ischemia/reperfusion [I/R] injury) mediated by toxic oxygen free radicals. Trapidil is currently used as a coronary artery vasodilating agent and is also used for the prevention of ischemic symptoms of cerebral vasospasm. The purpose of this study was to determine the effects of trapidil on I/R injury and the ischemic tolerance of rat peripheral nerves. METHODS: Preischemia or prereperfusion administration of trapidil (8 mg/kg) was evaluated in the rat sciatic nerve I/R injury model. Nerve tissue samples from the I/R injury site were assayed for malondialdehyde (MDA), nitrites, and nitrates, as markers of I/R injury, and pathological changes were evaluated by electron microscopy. RESULTS: I/R resulted in an increase in MDA levels, which remained elevated for 2 weeks in control nerves. Rats that received trapidil before ischemia exhibited decreased MDA levels, and rats that received trapidil after the standard 3 hours of ischemia demonstrated increased tolerance to reperfusion, as reflected in significantly decreased MDA levels. Nitrite and nitrate levels in trapidil-treated rats were significantly higher than those in control animals. Histological evaluations of the sciatic nerve segments demonstrated that preischemia and postischemia trapidil treatments had a sparing effect against the myelin damage and axonal edema that are consistently noted in untreated ischemic reperfused nerves. CONCLUSION: The results confirm that pretreatment with trapidil before the ischemic insult or before reperfusion provides marked protection against I/R injury in peripheral nerves.     

肠道部分缺血再灌注损伤诱发外周血淋巴细胞凋亡

目的：观察肠道部分缺血再灌注(I/R)损伤过程中外周血淋巴细胞凋亡及其在植物血凝素(PHA)刺激下增殖能力的变化。方法：大耳白兔55只,分为肠部分I/R组、假手术对照组、正常对照组,用自行设计的血流阻断器阻断SMA血流50%,维持4h,制作肠道部分缺血再灌注损伤动物模型。采用流式细胞术(AnnexinV/PI双染法)测定外周血淋巴细胞凋亡变化,采用免疫组织化学方法观察外周血淋巴细胞caspase-3蛋白的表达,采用MTT比色法测定外周血淋巴细胞增殖能力。结果：肠道缺血期外周血淋巴细胞凋亡率明显升高,肠道再灌注期后外周血淋巴细胞凋亡比例骤然减少;外周血淋巴细胞caspase-3表达与凋亡改变呈相同趋势;肠部分I/R损伤后外周血淋巴细胞增殖能力明显降低。结论：肠道部分I/R损伤后,外周血T-淋巴细胞增殖功能明显受抑,外周血淋巴细胞凋亡变化与细胞内caspase-3的表达有关。     

Recovery of neuromuscular function during reperfusion of the ischemic extremity: effect of mannitol and superoxide dismutase

The ability of mannitol and superoxide dismutase (SOD) to improve the recovery of peripheral nerve and skeletal muscle function and to influence metabolism during reperfusion after 4 hours of complete ischemia was investigated in an autoperfused canine hind-limb model. Study groups included control subjects (n = 7), subjects given 5000 units/kg of SOD intra-arterial bolus immediately before reperfusion and 10,000 units/kg infusion during first hour of reperfusion (n = 7), and subjects given 150 mg/kg isosmolar mannitol intra-arterial bolus before reperfusion and 1 gm/kg intravenous infusion during the first hour of reperfusion. Function was evaluated by determining isometric twitch and tetanic contractile force of paw dorsiflexion by stimulating the peroneal nerve or the anterior tibial muscle. Metabolic responses (oxygen consumption and lactate clearance) and blood flow were not influenced by either treatment protocol. However, mannitol significantly reduced muscle damage and significantly improved neuromuscular contractile function compared to control and SOD treatment regimens.     

鼠后肢周围神经缺血再灌注对脊髓腰膨大前角运动神经元超微结构的影响

目的 探讨大鼠后肢周围神经缺血再灌注对脊髓腰膨大前角运动神经元超微结构的影响及其内在关系。方法 采用无损伤动脉夹暂时阻断大鼠一侧髂总、髂内、髂外及股动脉的大鼠周围神经缺血的实验模型，透射电镜下观察不同缺血再灌注时间脊髓腰膨大灰质前角细胞的超微结构改变。结果 对照组神经元的超微结构形态正常，缺血6h，8h，12h3组均出现暗神经元改变。缺血8h组，除暗神经元改变外，还出现明确的细胞坏死。缺血12h组，神经元暗细胞变与大片神经组织坏死并存，血脑屏障严重破坏。在缺血6h，8h，12h各组内，随着再灌注时间的延长(60h以内)，神经元的损害明显逐渐加重。结论 大鼠后肢周围神经缺血再灌注可相应地引起脊髓腰膨大前角运动神经元超微结构的改变，可引起神经元的暗细胞变和坏死。在同一缺血组内，随着再灌注时间的延长，神经元的损害逐渐加重。     

肢体缺血再灌注损伤的新型动物模型制作

[目的]用充气止血带制作肢体缺血再灌注损伤的新型动物模型,研究其对周围神经和骨骼肌损伤的影响.[方法]选择健康新西兰大白兔6个月龄,30只,体重(3.5 ±0.3) kg,雌雄不限,在家兔左侧后肢环扎充气止血带,于不同时间点松开,造成左侧后肢缺血再灌注损伤的模型.随机分为3组,每组10只.A组:对照组,B组:缺血2h,C组:缺血4h.对照组不扎充气止血带,第1、2、3、4、5、6h检测肢体的神经电生理学指标,B组、C组于再灌注(松开止血带,血供恢复后)的1、2、3、4、5、6h检测肢体的神经电生理学指标,A组于第6h观察骨骼肌的形态,B、C组于再灌注(松开止血带,血供恢复后)的第6h观察骨骼肌的形态,每组于术后第5d评估左侧后肢的行走功能.[结果]随着缺血后再灌注时间的延长,B、C和A组相比较,周围神经的潜伏期延长、波幅降低,传导速度降低,三组之间的潜伏期、波幅、传导速度差异均有统计学意义(P＜0.05),光镜观察骨骼肌可见(B、C组):横纹紊乱、肌纤维断裂、间质血管扩张充血、大量中性粒细胞浸润.[结论]经过缺血期和再灌注损伤的交互作用后,肢体的功能性损伤进一步加重,出现了不可逆的病损.该模型制作对动物的损伤较小,更贴近临床.     

Warm ischemia induces alteration in lung immune cell functions

Warm ischemia is an important factor in early allograft dysfunction. To elucidate cellular events involved in such lung injury, we examined the effects of warm ischemia on the cytotoxic function of lymphocytes retrieved by bronchoalveolar lavage as compared with peripheral blood lymphocytes. Warm ischemia of the lung was induced in eight dogs by crossclamping left hilar structures for 1 hour. Bronchoalveolar cells from ischemia left and unaffected right lungs, as well as blood lymphocytes, were isolated before operation and 2 hours, 72 hours, and 7 days after operation. Lung and blood lymphocytes were assayed for natural killer and lectin-dependent cell-mediated cytotoxicity. Warm ischemia resulted in a significant impairment of natural killer activity within 2 hours of reperfusion (49% of preoperative control cytolysis, p less than 0.01). There was a significant increase in natural killer activity in bronchoalveolar lavage mononuclear cells 72 hours after reperfusion injury (178.4% of preoperative value, p less than 0.01). Interestingly, these functional alterations were not paralleled with changes seen in the peripheral blood lymphocytes or the opposite nonaffected lungs, where the natural killer activity appeared significantly depressed at 72 hours. Similarly, lectin-dependent cell-mediated cytotoxicity was noted to be increased in the bronchoalveolar lavage from the ischemic lung (179.5%, p less than 0.01) but decreased in the bronchoalveolar lavage from the nonaffected lung and peripheral blood lymphocytes at 72 hours after injury. We conclude that warm ischemia is associated with a functional alteration of the local lung immune cells. Such alteration is not observed in cells from the opposite lung or peripheral blood. The observed increase in nonspecific cytotoxicity of bronchoalveolar lymphocytes can be causative in the early damage seen in poorly preserved lung allografts.     

Extracellular flush solution that contains blood, mannitol, albumin, and prostacyclin protects rat lungs from six hours of ischemia.

We have used an isolated rat lung model to compare the quality of preservation of different flush techniques with each other and with topical cooling alone. Lung injury was assessed by recording lung weights after reperfusion after 4 and 6 hours of ischemia. The flush solutions studied were intracellular (Collins-Sacks), traditional extracellular, extracellular with low potassium plus dextran, and extracellular containing blood, mannitol, albumin, and prostacyclin (Wallwork's solution). Flushing with Wallwork's solution before both 4 and 6 hours of ischemia gave superior protection from lung edema after reperfusion over all the other methods.     

Influence of donor pretreatment with N-acetylcysteine on ischemia/reperfusion injury in rat kidney grafts

PURPOSE: N-acetylcysteine (NAC) has been shown to ameliorate ischemic acute renal failure. We determined the effect of donor pretreatment with NAC on ischemia reperfusion (I/R) injury in rat kidney grafts. MATERIALS AND METHODS: Lewis rats were divided into 3 groups (8 per group) and treated with saline, mannitol (1 gm/kg) or NAC (1 gm/kg intravenously) prior to donor nephrectomy. Cold stored kidneys (24 hours in UW solution) were transplanted into bilaterally nephrectomized recipients. Blood and graft tissue samples were taken 24 hours after transplantation for assessment of metabolic changes, histological damage and renal function. Metabolites associated with renal I/R injury were quantified in blood and renal tissue by magnetic resonance spectroscopy. RESULTS: The degree of histological damage was similar between the treatment groups. Of the counted tubules 60%were mildly damaged, whereas 40% showed moderate damage. Measurement of the metabolites allantoin and trimethylamine-N-oxide (TMAO) indicated a beneficial effect of NAC treatment. In graft tissue and recipient blood allantoin, a uric acid metabolite, was significantly lower in the NAC group vs the mannitol and saline groups (p <0.05). In recipient blood TMAO, an established marker of renal medullary injury, was significantly decreased in the NAC group vs mannitol and saline (p <0.05). Serum creatinine levels were not different between treatment groups. CONCLUSIONS: Donor pretreatment with NAC preserves renal metabolism and may improve outcomes of I/R injured kidney transplants. Allantoin and TMAO are sensitive metabolic markers of renal I/R injury that can be detected before the onset of functional and morphological changes.     

Intermittent reperfusion fails to prevent posttourniquet neurapraxia.

This study examined the effects of intermittent reperfusion on peripheral nerve function. Rabbits were randomized to undergo 4 hours of 350 mm Hg tourniquet compression to a hind limb either continuously, interrupted by a single 10-minute reperfusion interval after 2 hours, or interrupted by 10 minutes of reperfusion after each hour. A control group had the tourniquet applied for 4 hours but it was never inflated. The animals were examined clinically for neuromuscular dysfunction and the structure and function of the peripheral nerves were evaluated 1 week after tourniquet compression. Animals that underwent compression had a foot drop and decreased toe-spread reflex. There was greater intraneural edema and slower nerve conduction velocity in nerve segments that were directly compressed by the tourniquet but no apparent abnormalities in segments distal to the tourniquet. Intermittent reperfusion failed to diminish the clinical, structural, or functional consequence of the neurologic injury.     

缺血预处理减轻大鼠肝缺血再灌注损伤的免疫机制研究

目的探讨大鼠肝缺血再灌注损伤(HIRI)的免疫机制和缺血预处理(IPC)的保护作用。 方法80只大鼠被随机分为假手术组(A组)、肝门阻断20 min组(B组)、30 min组(C组)、40 min组(D组)以及肝门阻断30 min前预处理组(E组),每组再分为再灌注2 h亚组和24 h亚组,各8只。检测再灌注后2 h、24 h的血丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、白细胞介素10、12(IL-10、IL-12)以及外周血T淋巴细胞亚群的水平,观察再灌注后2 h、24 h时的存活率及肝脏病理情况。 结果随着肝门阻断时间的延长,ALT、AST显著升高,肝内炎症细胞浸润增加,24 h存活率逐渐降低。D组再灌注2 h时,CD8+ T淋巴细胞显著升高,CD4+/CD8+比值下降,调节性T淋巴细胞显著减少,血清IL-10显著降低,而IL-12水平显著升高。再灌注后24 h,B组大鼠各项指标逐步恢复至假手术组水平,而D组大鼠CD4+T淋巴细胞、CD4+/CD8+比值尤其是Treg显著升高,且IL-10水平显著升高,IL-12水平明显降低。与C组相比,E组阻断30 min后无一例死亡,再灌注2 h的ALT、AST水平显著降低,Treg和IL-10水平显著升高,IL-12水平明显降低,再灌注24 h后各项指标恢复并接近假手术组水平,肝脏病理损伤较轻。 结论肝缺血再灌注引起肝脏损伤甚至死亡,可能与诱导T淋巴细胞尤其是Treg和细胞因子的紊乱有关。缺血预处理可以增加再灌注早期的Treg细胞,有效纠正免疫紊乱,减轻损伤。