大鼠脑缺血再灌注后Caspase-3、Bcl-2和Bax的表达

目的探讨大鼠脑缺血再灌注后caspase-3、Bcl-2和Bax在脑皮质神经元中的表达。方法将动物随机分为假手术组及缺血组,参照zea longa线栓法建立大鼠左侧大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)局灶性脑缺血再灌注模型,各组大鼠分别在左侧MCAO2h再灌注不同时间点断头取脑,脑皮质神经元中caspase-3、Bcl-2和Bax的表达通过免疫组化法来测定。结果缺血组大鼠脑皮质caspase-3的表达较假手术组显著增强(P<0.01),缺血组大鼠脑皮质Bcl-2的表达较假手术组显著增强(P<0.01),缺血组大鼠脑皮质Bax的表达较假手术组显著增强(P<0.01)。结论短暂性脑缺血再灌注上调脑皮质神经元中caspase-3和Bax的表达促细胞凋亡,上调脑皮质神经元中Bcl-2的表达抗细胞凋亡。     

缺血后处理对大鼠脑缺血再灌注损伤神经保护作用的研究

目的探讨大鼠脑缺血后处理对缺血再灌注损伤后神经元的保护作用。方法健康雄性SD大鼠30只,随机分为假手术组(SO组)、缺血再灌注对照组(MCAO组)、缺血后处理组(IPOC组)3组。采用线栓法制备大鼠MCAO模型及IPOC模型,分别用TTC染色法计算脑梗死体积、流式细胞术和ELISA法观察,对于大鼠缺血半暗带神经细胞凋亡率及血清神经元特异性烯醇化酶(NSE)含量的影响。结果 (1)大鼠脑缺血再灌注后24h,IPOC组较MCAO组梗死体积明显减小(P<0.05);(2)MCAO组大鼠脑缺血再灌注24h细胞凋亡发生率及血清中NSE的含量较SO组显著增加(P<0.01);(3)IPOC组神经元凋亡发生率及血清NSE较MCAO组显著降低(P<0.05或0.01)。结论大鼠脑缺血后处理对缺血再灌注神经元损伤有保护作用。     

慢性间歇性缺氧对大鼠局灶性脑缺血再灌后神经细胞凋亡的影响

目的观察慢性间歇性缺氧(CIH)对大鼠脑缺血再灌注后脑梗死体积、神经元形态结构、细胞凋亡、B细胞淋巴瘤/白血病-2基因(B-cell lymphoma/leukemia-2gene,Bcl-2)、Bax表达的变化,探讨其对大鼠脑缺血再灌注后可能的神经损害作用机制。方法采用自制CIH系统对SD大鼠进行干预,然后采用Zea Longa等方法制备局灶性脑缺血再灌动物模型。将42只SD大鼠随机分为假手术组(n=6)、模型组(n=12)、CIH 4周组(n=12)、CIH8周组(n=12),光镜观察受损脑组织细胞的形态学改变,免疫组织化学染色法检测脑组织Bcl-2和Bax蛋白表达水平,TUNEL法检测脑细胞凋亡情况,TTC染色检测梗死体积,利用神经功能缺损评分评价神经功能缺损情况。结果 TUNEL染色阳性细胞主要分布在坏死灶的周边和皮质区。CIH8周组大鼠脑梗死体积、神经功能缺损评分、脑细胞凋亡数高于模型组和CIH 4周组(均P0.05)。与模型组比较,CIH8周组Bcl-2蛋白表达降低(P0.05),Bax蛋白表达增强(P0.05),Bcl-2/Bax比值降低(P0.05),CIH4周组Bcl-2蛋白表达及Bcl-2/Bax比值亦较模型组降低(P0.05)。而CIH8周组和CIH4周组间Bcl-2、Bax蛋白表达及Bcl-2/Bax比值比较无统计学差异(P0.05)。结论 (1)CIH可增加脑缺血再灌后大鼠神经功能缺损、梗死体积。(2)随CIH时间延长,大鼠脑缺血后缺血半暗带的细胞凋亡增加,Bax蛋白表达上调,Bcl-2蛋白表达下调。Bcl-2/Bax的变化可能参与了CIH对脑缺血后细胞凋亡过程的调控。     

七叶皂苷钠对大鼠脑缺血再灌注损伤的保护作用

目的 探讨七叶皂苷钠对大鼠脑缺血再灌注损伤的作用及机制。方法 60只成年SD大鼠随机分为假手术组、模型组和七叶皂苷钠组,各20只。采用线栓法建立大鼠局灶性大脑中动脉闭塞再灌注损伤模型,七叶皂苷钠组建模成功后1 h腹腔注射七叶皂苷钠（2.8 mg/kg）,假手术组和模型组腹腔注射等量生理盐水。造模后24 h,使用Longa评分评估大鼠神经功能损伤程度,使用称重法检测大鼠脑水肿程度,使用ELISA法测定大鼠损伤脑组织超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、丙二醛（MDA）、肿瘤坏死因子（TNF-α）、白细胞介素6（IL-6）及白细胞介素1β（IL-1β）的含量,使用TUNEL法检测损伤脑组织神经元凋亡率,使用蛋白免疫印迹法检测损伤脑组织双特异性磷酸酶1（DUSP1）、核转录因子-κB（NF-κB）p65、Bcl-2及Bax蛋白的表达。结果 与假手术组比较,模型组大鼠Longa评分显著增加（P<0.01）,脑含水量显著升高（P<0.01）,损伤脑组织MDA、TNF-α、IL-1β和IL-6水平显著增高（P<0.001）,损伤脑组织SOD和CAT水平显著降低（P<0.001）,损伤脑组织神经元凋亡率显著升高（P<0.01）,损伤脑组织DUSP1和Bcl-2蛋白表达水平显著降低（P<0.05）,损伤脑组织NF-kB p65和Bax蛋白表达水平显著增高（P<0.05）。七叶皂苷钠显著逆转大鼠上述反应（P<0.05）。结论 七叶皂苷钠显著改善大鼠脑缺血再灌注损伤,机制可能与减轻炎症反应、氧化应激反应、神经元凋亡等有关。     

人尿激肽原酶对急性局灶性脑缺血再灌注损伤大鼠细胞凋亡的影响

目的 研究人尿激肽原酶(HUK)对大鼠急性局灶性脑缺血再灌注(FCIR)损伤后细胞凋亡数量及B细胞淋巴瘤/白血病-2(Bcl-2)、Bcl-2联合X蛋白(Bax)蛋白表达的影响.方法 84只雄性SD大鼠分为假手术组(12只)、脑缺血再灌注(IR)组(36只)、HUK处理组(36只),IR组和HUK处理组剩余大鼠又按照再灌注时间6 h、12 h、24 h、72 h、168 h分为5个亚组(均为6只).建立大鼠大脑中动脉FCIR模型.假手术组、IR组及HUK处理组中各取6只SD大鼠用于测定梗死体积,其余大鼠用于观察神经功能缺陷评分、TIJNEL法及免疫组化检测凋亡细胞数量及凋亡蛋白Bcl-2、Bax的表达.结果 HUK处理组神经功能缺陷评分、梗死灶体积、除168 h亚组外的各时 间点的凋亡细胞数及Bax蛋白表达均显著少于IR组(P＜0.05),除168 h亚组外的各时间点的Bcl-2蛋白表达均显著高于IR组(P＜0.05).结论 HUK对FCIR后的脑组织起保护作用,其机制可能为损伤后3 d内通过上调Bcl-2、下调Bax蛋白表达来抑制细胞凋亡.     

局灶性脑缺血再灌注大鼠海马CA1区神经元凋亡研究

目的 观察大鼠局灶性脑缺血再灌注(ischemia reperfusion,I/R)损伤后海马CA1区神经元凋亡、TUNEL阳性细胞变化,以及凋亡相关蛋白Bcl-2与Bax蛋白的表达情况.方法 将健康雄性SD (Sprague-Dawley)大鼠随机分为假手术组和I/R组,每组再分为缺血再灌注后3、6、12、24、48、72 h亚组.应用免疫组化方法检测再灌注后不同时间点大鼠海马CA1区神经元凋亡基因Bcl-2和Bax蛋白的表达及Bcl-2/Bax比值变化,采用原位细胞凋亡检测(TUNEL)技术检测凋亡阳性细胞数.结果 各组非缺血侧相应区域神经元胞质中Bcl-2均有微弱表达.I/R组缺血侧海马CA1区于再灌注3 h开始出现Bcl-2和Bax蛋白微弱表达,随再灌注时间延长神经元内Bcl-2表达逐渐增强,再灌注24 h后Bcl-2表达达高峰,假手术组与I/R组比较差异有统计学意义(P<0.05).结论 I/R损伤后海马CA1区神经元不仅存在变性坏死,还存在明显的细胞凋亡且细胞凋亡在大鼠I/R损伤中发挥重要作用;I/R可诱导海马CA1区细胞凋亡基因Bcl-2和Bax蛋白表达,且其表达呈一定规律.     

雌二醇对慢性脑缺血大鼠学习记忆能力及额叶凋亡相关蛋白表达的影响

目的 研究17-β雌二醇对慢性脑缺血大鼠学习记忆能力及额叶Bcl-2、Bax蛋白表达的影响. 方法 双侧颈总动脉结扎法制备前脑缺血致血管性痴呆大鼠模型,将大鼠随机分为假手术组、模型组和治疗组,每组20只,观察雌二醇的保护作用.通过Y-型迷宫测试大鼠学习记忆能力,HE染色观察大鼠额叶皮质神经元的形态变化,免疫组化染色检测Bcl-2、Bax的表达. 结果 模型组与假手术组相比学习记忆能力明显下降(P＜0.01), 皮质Bcl-2、Bax免疫阳性细胞数增加(P＜0.01).17-β雌二醇组与模型组相比学习记忆能力明显改善(P＜0.01),皮质Bcl-2免疫阳性细胞数明显增加(P＜0.01),Bax免疫阳性细胞数明显减少(P＜0.01). 结论 17-β雌二醇可能通过调节Bcl-2、Bax蛋白表达来抑制额叶皮质细胞凋亡,从而改善慢性脑缺血大鼠的记忆能力.     

小续命汤有效成分对慢性脑缺血大鼠氧化应激损伤及细胞凋亡的影响

目的 探讨小续命汤有效成分对慢性脑缺血大鼠氧化应激损伤及神经细胞凋亡的影响.方法 采用永久性结扎双侧颈总动脉法建立慢性脑缺血大鼠模型,将造模成功的大鼠按随机数字表法分为模型组、银杏叶提取物组和小续命汤有效成分低、中、高剂量组;另设假手术组作为对照.采用分光光度法检测各组大鼠脑组织超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)活性和丙二醛(MDA)含量的变化,TUNEL法检测神经细胞凋亡情况,Western blotting检测细胞凋亡相关蛋白caspase-3、Bcl-2、Bax的表达变化.结果 与模型组相比,低剂量和中剂量小续命汤有效成分可显著抑制慢性脑缺血大鼠长期缺血缺氧导致的氧化应激反应,表现为降低脂质过氧化水平及增强脑组织抗氧化酶GSH-Px活性,差异有统计学意义(P＜0.05),但对SOD和CAT活性无显著影响.与模型组相比,中剂量小续命汤有效成分可显著减少慢性脑缺血大鼠神经细胞的凋亡率,同时低剂量和中剂量小续命汤有效成分还可显著升高脑组织Bcl-2/Bax比值,抑制下游Caspase凋亡级联反应,差异均有统计学意义(P＜0.05).结论 小续命汤有效成分可显著抑制慢性脑缺血导致的氧化应激损伤,减少神经细胞凋亡.     

醒脑静联合丁苯肽对脑缺血再灌注损伤后细胞凋亡的影响

目的 观察醒脑静、丁苯酞及二者联合分别对大鼠脑缺血再灌注损伤后神经细胞凋亡及Bcl-2和Bax表达的影响。方法 60只雄性wistar大鼠(250±20)g采用改良线栓法制作脑缺血再灌注损伤模型(Middle cerebral artery occlusion,MCAO),随机分为4组,即模型组、醒脑静组、丁苯酞组、醒脑静联合丁苯酞(联合用药)组,每组又分为6、24、72 h三个亚组; 通过原位末端转移酶标记技术(TUNEL)检测神经细胞凋亡情况,采用免疫组化法观察大鼠脑缺血再灌注各个时间点Bcl-2、Bax的表达水平。结果(1)模型组手术对侧大脑半球偶见凋亡细胞,病灶区可见大量神经细胞凋亡。丁苯酞用药组、醒脑静用药组凋亡细胞数明显减少,醒脑静联合丁苯酞组凋亡细胞数最少(P<0.05);(2)丁苯酞组及联合用药组Bcl-2阳性表达水平较模型组均有提高,联合用药组Bcl-2阳性表达水平在各时间点均最高(P<0.05); 丁苯酞组及联合用药组Bax阳性表达水平较模型组均有降低,联合用药组Bax阳性表达水平最低(P<0.05)。结论(1)醒脑静、丁苯酞及二者联合均可能通过抑制脑缺血再灌注损伤后神经细胞凋亡来实现神经细胞保护作用,其中二者联合效果最佳;(2)丁苯酞可能通过增加脑缺血再灌注损伤大鼠Bcl-2表达,减少Bax表达的方式来减少神经细胞凋亡,从而减轻脑缺血再灌注损伤;(3)醒脑静本身不能对Bcl-2、Bax的表达水平产生影响,但其可能通过增强丁苯酞作用的方式影响Bcl-2、Bax的表达,从而减轻脑缺血再灌注损伤。     

人脂肪组织来源的神经干细胞移植对大鼠局灶性脑缺血再灌注后细胞凋亡及Bcl-2、Bax蛋白表达的影响

目的 探讨人脂肪组织来源的神经干细胞移植对大鼠局灶性脑缺血再灌注后细胞凋亡及Bcl-2、Bax蛋白表达的影响.方法 线栓法制作大鼠大脑中动脉缺血2 h再灌注模型.60只健康雄性SD大鼠随机分为4组:正常对照组(6只),假手术组(6只),缺血对照组(24只)和移植治疗组(24只);后2组又分为再灌注7 d、14 d、21 d、28 d组(各6只).体外培养脂肪基质细胞,诱导分化为神经干细胞.造模成功后24h,移植治疗组经尾静脉移植人脂肪组织来源的神经干细胞悬液(细胞浓度为2×106/ml),缺血对照组经尾静脉注射生理盐水,假手术组不做任何处理.TUNEL法检测细胞凋亡,免疫组化SABC法检测Bcl-2、Bax表达.结果 与缺血对照组比较,移植治疗组各时间点的细胞凋亡数均明显减少(均P＜0.01),Bcl-2阳性细胞数明显增高(均P＜0.01),Bax阳性细胞数明显减少(P＜0.05～0.01).结论 人脂肪组织来源的神经干细胞可能通过上调Bcl-2蛋白表达、下调Bax蛋白表达,减少局灶性脑缺血细胞凋亡;对脑缺血再灌注损伤后的神经细胞起保护作用.     

Effects of Rubus parvifolius L. on neuronal apoptosis and expression of apoptosis-related proteins in a rat model of focal cerebral ischemic-reperfusion injury*★

BACKGROUND： Studies have shown that the Rubus parvifolius L. （RP） plant extract exhibits protective effects on cerebral ischemia. This effect is reflected in altered ischemic neuronal apoptosis and associated protein expression.
OBJECTIVE： To explore the neuroprotective mechanism of RP after cerebral ischemia injury.
DESIGN, TIME AND SETTING： Randomized control experiment of cellular, molecular, and protein levels. The experiment was completed at Chongqing Medical University at the School of Pharmacy Laboratories and Basic Medical Institute from October 2005 to January 2006.
MATERIALS： Twenty-four adult, male, Wistar rats, weighing （28 ± 20） g. RP extract, which was a product of ethanol extraction, was provided by the Laboratory of Pharmaceutical Analysis, Chongqing Medical University. RP was dissolved in distilled water to a concentration of 10 mg/mL. All rats were randomly assigned into four groups： 5 g/kg RP, 10 g/kg RP, model, and sham-surgery, with 6 rats in each group.
METHODS： In the 5 and 10 g/kg RP groups, as well as the model group, the middle cerebral artery was occluded （MCAO） for 60 minutes, resulting in focal cerebral ischemia, followed by reperfusion for 24 hours. Rats in the 5 and 10 g/kg RP groups received 5 and 10 g/kg RP, respectively. The RP treatment group received RP intragastrically （once a day） for 3 days. One hour after the last dose, rats were subjected to MCAO. The same surgical procedure was performed in the sham-surgery group, except the suture was introduced into the external carotid artery, but not advanced. Rats in the model group were subjected to MCAO. The sham-surgery and model groups received intragastrically administered normal saline once per day for 3 days. One hour after the last dose, the rats were subjected to surgery.
MAIN OUTCOME MEASURES： TUNEL labeling and immunohistochemical methods were used to investigate changes in neuronal apoptosis and expression of the apoptosis-related proteins, Bax and Bcl-2, on the ischemic hemisphere     

川芎嗪对大鼠重型颅脑损伤后神经细胞凋亡及Bcl-2、Bax表达的影响

目的探讨川芎嗪对大鼠重型颅脑损伤后神经细胞凋亡及相关基因Bcl-2、Bax表达的影响和对脑神经的保护作用。方法120只SD健康大鼠随机分为假手术组、模型组、治疗组,其中模型组和治疗组采用Feeney自由落体撞击装置制作大鼠重型颅脑损伤模型,治疗组给予盐酸川芎嗪,用TUNEL及免疫组化法检测三组间细胞凋亡及Bcl-2、Bax蛋白的表达情况。结果大鼠脑组织中细胞凋亡率及Bcl-2、Bax表达水平在治疗组和模型明屁高于假手术组（P〈0．05）。在伤后72h、168h,治疗组的细胞凋亡率及Bax表达水平明显低于模型组,而Bcl-2的表达水平则明显高于模型组（P〈0．05）。结论川芎嗪可能通过抑制Bax的表达,上调Bcl-2的表达,减少神经细胞凋亡,减轻重型颅脑损伤后继发脑损害,从而发挥脑神经保护作用。     

Effects of Rubus parvifolius L. on neuronal apoptosis and expression of apoptosis-related proteins in a rat model of focal cerebral ischemic-reperfusion injury

BACKGROUND:Studies have shown that the Ruhus parvifolius L.(RP)plant extract exhibits protective effects on cerebral ischemia.This effect is reflected in altered ischemic neuronal apoptosis and associated protein expression.OBJECTIVE:To explore the neuroprotective mechanism of RP after cerebral ischemia jniury.DESIGN,TIME AND SETTING:Randomized control experiment of cellular,molecular.and protein levels.The experiment was completed at Chongqing Medical University at the School of Pharmacy Laboratories and Basic Medical Institute from October 2005 to January 2006.MATERIALS:Twenty-four adult,male,Wistar rats,weighing(28±20)g.RP extract,which was a product of ethanol extraction.was provided by the LabOratory of Pharmaceutical Analysis,Chongqing Medical University.RP was dissolved in distilled water to a concentration of 10 mg/mL.All rats were randomly assigned into four groups:5 g/kg RP,10 g/kg RP,model,and sham-surgery,with 6 rats in each group.METHODS:In the 5 and 10 g/kg RP groups,as well as the model group,the middle cerebral artery was occluded(MCAO)for 60 minutes,resulting in focal cerebral ischemia,followed by reperfusion for 24 hours.Rats in the 5 and 10 g/kg RP groups received 5 and 10 g/kg RP,respectively.The RP treatment group received RP intragastrically(once a day)for 3 days.One hour after the last dose,rats were subjected to MCAO.The same surgical procedure was performed in the sham-surgery group,except the suture was introduced into the extemal carotid artery,but not advanced.Rats in the model group were subjected to MCAO.The sham-surgery and model groups received intragastrically administered normal saline once per day for 3 days.One hour after the last dose,the rats were subjected to surgery.MAIN OUTCOME MEASURES:TUNEL labeling and immunohistochemical methods were used to investigate changes in neuronal apoptosis and expression of the apoptosis-related proteins.Bax and Bcl-2.on the ischemic hemisphere,as well as the contralateral hemisphere,after administration of RP or normal saline.RESULTS:All 24 Wistar rats were included in the final analysis.without any loss.Compared with the sham-surgery group,the number of the TUNEL-positive cells in the model group,as well as the 5 and 10 g/kg RP treatment groups,were significantly increased in the ischemic hemisphere(P<0.05).Compared with the sham-surgery group,the number of Bcl-2-positive and Bax-positive cells increased significantly in the model group(P<0.01).The number of Bcl-2-positive cells increased,and the number of Bax-positive cells decreased in the model group,compared to the 5 and 10 g/kg RP treatment groups(P<0.05-0.01).CONCLUSION:RP can prevent neuronal apoptosis following cerebral ischemic-reperfusion of rats.The mechanism underlying the RP-induced neuroprotection in the cerebral ischemia iniury may be related to increased Bcl-2 expression and decreased Bax expression.     

Electroacupuncture Alleviated Neuronal Apoptosis Following Ischemic Stroke in Rats via Midkine and ERK/JNK/p38 Signaling Pathway

This study aimed to evaluate the effects of electroacupuncture (EA) intervention administered at rats of middle cerebral artery occlusion (MCAO)/reperfusion. Fifty-four male Sprague-Dawley rats were divided into three groups, consisting of sham group, MCAO/R group, and EA group. EA treatment at Quchi and Zusanli acupoints was applied in rats of EA group at 24 h after MCAO once per day for 3 days. Our results indicated that EA treatment reduced infarct volumes and neurological deficits, as well alleviated the apoptotic cells in peri-infarct cortex, indicating that EA exerted neuroprotective effect in cerebral ischemic rats. Moreover, EA treatment may effectively reverse the upregulation of caspase-3 and Bim and alleviate the inhibition of Bcl-2 following 72-h ischemic stroke. EA may significantly reverse the promoted relative density level of p-ERK1/2, p-JNK, and p-p38 in the EA group compared with the MCAO/R group. In addition, the growth factor midkine (MK) was upregulated at 72 h after MCAO/R, and EA treatment may significantly prompt expression of MK. Our study demonstrated that EA exerted neuroprotective effect against neuronal apoptosis and the mechanism might involve in upregulation of MK and mediation of ERK/JNK/p38 signal pathway.     

Effects of acupoint versus non-acupoint electroacupuncture on cerebral cortical neuronal Bcl-2, Bax and caspase-3 expression in a rat model of focal cerebral ischemia

BACKGROUND： Several studies have demonstrated that electroacupuncture by acupoint selection can inhibit cerebral cortical neuronal apoptosis following cerebral ischemia/reperfusion. OBJECTIVE： To validate the effects of electroacupuncture by acupoint selection on the expression level of cortical neuronal anti-apoptotic Bcl-2 protein and the apoptotic executive protein, caspase-3, in rat models of focal cerebral ischemia/reperfusion. DESIGN, TIME AND SETTING： This randomized grouping, neural cell and molecular biology animal experiment was performed at the Laboratory of Pharmacology of Traditional Chinese Medicine and the Laboratory Animal Center of Henan Institute of Traditional Chinese Medicine between November 2006 and May 2007. MATERIALS： Atotal of 40 healthy male adult Sprague-Dawley rats were randomly and evenly divided into four groups： sham-operated, model, electroacupuncture and non-aeupoint control. G6895 electro-acupuncture instruments were purchased from Shanghai Huayi Instrument Factory, China. Caspase-3, Bcl-2 and Bax kits were provided by Wuhan Boster Bioengineering Co., Ltd., China. METHODS： Middle cerebral artery occlusion was induced in the model, electroacupuncture and non-acupoint groups. In the electroacupuncture group, the acupoints Jianyu （LII5）, Waiguan （S J5）, Biguan （ST31）, and Zusanli （ST36） were given electroacupuncture. In the non-acupoint control group, at each time point （immediately after ischemia and after reperfusion, or 2 hours after reperfusion）, electroacupuncture was performed at the midpoints of Tianquan （PC2）-Quze （PC 3） line, Quze （PC 3）-Ximen （PC4） line, Zuwuli （LR10）-Yinbao （LR9） line, and Xiguan （LR7）-Zhongdu （LR6） line. Electroacupuncture parameters were set with a continuous wave with a frequency of 10 Hz, wave width 0.6 ms, voltage 1.5-3.0 V, and a duration of 10 minutes. The sham-operated and model groups received only animal fixation without electroacupuncture procedure. MAIN OUTCOME MEASURES： Five ra     

Neuroprotective effects of different frequency preconditioning exercise on neuronal apoptosis after focal brain ischemia in rats

ABSTRACT

Objective: Preconditioning exercise can exert neuroprotective effects after stroke; however, the effects of exercise intensity, frequency, duration are unknown. We investigated the neuroprotective effect of different frequency preconditioning exercise on neuronal apoptosis after cerebral ischemia in rats.

Methods: Rats were divided into the following five groups: 5 times a week of exercise (5/w-Ex) group, 3 times a week of exercise (3/w-Ex) group, once a week of exercise (1/w-Ex) group, no exercise (No-Ex) group, and intact control (control) group. Rats were made to run on a treadmill for 30 min per day at a speed of 25 m/min for 3 weeks. After the running program, the rats were subjected to 60-min left middle cerebral artery occlusion. Two days after ischemia, the cerebral infarct volume, neurological and motor function, Bcl-2-associated X protein (Bax)/B-cell lymphoma 2 (Bcl-2) ratio, expression of caspase-3, and TUNEL positive cells were examined in the cerebral cortex surrounding the ischemic zone.

Results: The 3/w-Ex and 5/w-Ex groups showed significantly reduced infarct volumes compared with the No-Ex group, but the 1/w-Ex group did not. In addition, the 3/w-Ex and 5/w-Ex groups had improved neurological scores and sensorimotor function compared with the No-Ex group. The Bax/Bcl-2 ratio, expression of caspase-3, and TUNEL-positive cells significantly decreased in the penumbra area in the 3/w-Ex or 5/w-Ex groups compared with the No-Ex group.

Discussion: Our findings suggested that three times or more per week of high-intensity preconditioning exercise exert neuroprotective effects through the downregulation of the Bax/Bcl-2 ratio and caspase-3 activation after stroke.

Abbreviations: TUNEL: terminal deoxynucleotidyl transferase-mediated biotinylated dUTP nick and labeling; MCAO:middle cerebral artery occlusion; BAX:Bcl-2-associated X protein; Bcl-2: B-cell lymphoma 2; TTC: 2,3,5-triphenyltetrazorlium chloride