低氧、耐力训练对大鼠代谢酶及肌球蛋白Ca-ATPase的影响

目的:了解低氧及耐力练习对骨骼肌氧化酶、糖酵解酶和肌球蛋白Ca- ATPase的影响,从而间接判断低氧及耐力训练条件下肌肉收缩速度及耐力等特性的改变。方法:4 0只雄性SD鼠随意分成常氧安静组、常氧运动组、低氧安静组、低氧运动组;运动形式为跑台练习,跑台坡度12°,跑速2 2 m/ min,持续时间6 0 min/天;2 8天后测定琥珀酸脱氢酶、乳酸脱氢酶和肌球蛋白Ca- ATPase活性。结果:低氧两个组肌球蛋白Ca- ATPase活性均高于常氧安静组;低氧安静组比常氧安静组乳酸脱氢酶的活性增加;常氧耐力组、低氧安静组及低氧耐力组琥珀酸脱氢酶的活性均增加。结论:低氧可增加肌纤维收缩速度,同时增加氧化酶和糖酵解酶的活性;常氧和低氧耐力练习均增加氧化酶的活性。

基于家族分析的苜蓿逆境应答Ca^(2+) ATPase家族基因筛选与鉴定

Ca^(2+) ATPase属于P型ATPase超家族,在植物对外界逆境的应答中发挥重要作用,但迄今尚未有苜蓿Ca^(2+) ATPase基因研究的相关报道。为筛选逆境胁迫应答Ca^(2+) ATPases,本研究鉴定获得了16个苜蓿Ca^(2+) ATPase家族成员,分布在7条染色体上,且存在一对旁系同源基因。系统进化分析表明苜蓿Ca^(2+) ATPases分为ACA和ECA亚家族,ACA亚家族分为4组,且组内成员具有相似的内含子-外显子组成模式。此外,苜蓿Ca^(2+) ATPase家族具有高度保守的蛋白序列组成,包括4个功能结构域、10个跨膜结构域和11个保守motif。转录组数据分析发现该家族具有不同的逆境诱导表达模式,且多数苜蓿Ca^(2+) ATPases家族基因受低温和冷冻胁迫诱导表达,其中Mt ACA9和Mt ACA8上调表达最明显。q RT-PCR结果证实Mt ACA9和Mt ACA8表达在低温和冷冻胁迫下显著上调。本研究结果为揭示苜蓿Ca^(2+) ATPase基因在低温冷害应答中的功能提供了重要参考。

温度对南美白对虾肌原纤维蛋白质性质的影响

南美白对虾是当今世界养殖虾类产量最高的三大品种之一,因此研究虾的保鲜具有重要意义。以肌原纤维蛋白质的变化为依据,反映南美白对虾的鲜度和加工特性,考查不同温度对南美白对虾蛋白质性质的影响。结果表明在40℃时,肌原纤维Ca-ATPase的失活速度与溶解度下降速度接近,肌原纤维蛋白在较短的时间内发生变性;30℃时溶解度的下降比Ca-ATPase的失活速度快。在以上两个温度下,Ca-ATPase的失活速度均遵循一级反应定律;低温下(0℃,4℃)Ca-ATPase的变化与溶解度的变化差别不明显,表明肌原纤维蛋白质的变性速度明显减慢。

心力衰竭大鼠心肌β_3肾上腺素受体表达及其对钙离子相关调节蛋白的作用

目的研究心力衰竭(HF)大鼠心肌β3肾上腺素受体(beta3-adrenergic receptors,β3-AR)表达情况及对钙离子相关调节蛋白的作用。方法以正常大鼠作对照组,皮下注射生理盐水;实验组大鼠皮下注射异丙肾上腺素(Isoproterenol,ISO),常规饲养8w。造模成功后实验组随机分为3组,激动剂组给予尾静脉注射β3-AR激动剂BRL37344,抑制剂组给予尾静脉注射β3-AR抑制剂SR59230A,HF组给予生理盐水。用药8w后行心脏彩超、RT-PCR法检测心肌组织钙调蛋白(CaM)、钙调蛋白激酶Ⅱ(CaMKⅡ)、肌内质网Ca2+-ATP酶异构体2a(SERCA2a)的mRNA表达。结果①HF组较对照组β3-ARmRNA表达水平增高,CaM、CaMKⅡ、SERCA2amRNA表达水平减低(均P<0.05)。②与HF组相比较,激动剂组β3-ARmRNA水平表达增加,CaM、CaMKⅡ、SERCA2a表达进一步减少(均P<0.05)。③抑制剂组β3-ARmRNA表达水平较对照组减少,CaM、CaMKⅡ、SERCA2a较对照组减低,但较HF组增加(均P<0.05)。结论β3-AR激动剂减低衰竭心肌CaM、CaMKⅡ、SERCA2a的mRNA表达,导致心功恶化,β3-AR抑制剂则相反,可延缓HF进展,预示β3-AR抑制剂在药物治疗HF中的应用前景。

长时间运动对大鼠骨骼肌红、白肌纤维肌浆网功能的影响

大鼠以18m／min的速度运动100min后，测定股四头肌和腓肠肌的浅层、深层的白肌、红肌肌浆网Ca2＋--Mg2＋ATPase活性和Ca2＋转运。结果发现，大鼠长时间运动后骨骼肌肌浆网功能下降，红肌比白肌变化明显。这一结果提示运动性骨骼肌疲劳可能与肌浆网功能下降有关。

Shen-Fu Injection(参附注射液)Alleviates Post-resuscitation Myocardial Dysfunction by Up-regulating Expression of Sarcoplasmic Reticulum Ca2+-ATPase

Objective： To compare the effect of Shen-Fu Injection （SFI） and epinephrine on the expression of sarcoplasmic reticulum Ca2. ATPase 2a （SERCA2a） in a pig model with post-resuscitation myocardial dysfunction. Methods： Ventricular fibrillation （VF） was electrically induced in Wu-zhi-shan miniature pigs. After 8 min of untreated VF and 2 min of cardiopulmonary resuscitation （CPR）, all animals were randomly administered a bolus injection of saline placebo （SA group, n=10）, SFI （0.8 mg/kg, SFI group, n=10） or epinephrine （20 t~ g/kg, EPI group, n=10）. After 4 min of CPR, a 100-J shock was delivered. If the defibrillation attempt failed to attain restoration of spontaneous circulation （ROSC）, manual chest compressions were rapidly resumed for a further 2 rain followed by a second defibrillation attempt. Hemodynamic variables were recorded, and plasma concentrations of catecholamines were measured. Adenylate cyclase （AC）, cyclic adenosine monophosphate （cAMP） and the expressions of 13 1-adrenoceptor （AR） and SERCA 2a were determined. Results： Cardiac output, left ventricular dp/dtr,~x and negative dp/dtm^x were significantly higher in the SFI group than in the SA and EPI groups at 4 and 6 h after ROSC. The expression of 13 1-AR and SERCA2a at 24 h after ROSC were significantly higher in the SFI group than in the SA and EPI groups （P〈0.05 or P〈0.01）. Conclusions： The administration of epinephrine during CPR decreased the expression of SERCA2a and aggravated postresuscitation myocardial function （P〈0.01）. SFI attenuated post-resuscitation myocardial dysfunction, and the mechanism might be related to the up-regulation of SERCA2a expression.

A Comparative Study on the Therapeutic Effect of Astragaloside (黄芪总皂甙) and Perindopril in Treating CVB_3-Infected Cardiomyocytes in Rats

Objective: To compare the therapeutic effects of Astragaloside and Perindopril on myocardial sarco/endoplasmic reticulum Ca 2+ ATPase (SERCA) activity and the SERCA type 2 mRNA level in Coxsackievirus B 3 (CVB 3) infected cardiomyocytes. Methods: Cultured cardiomyocytes of rats were divided into normal, model, Astragaloside and Perindopril groups. The model, Astragaloside and Perindopril groups were infected with CVB 3. Meanwhile, the Astragaloside and the Perindopril groups were treated with Astragaloside (10 μg/ml) and Perindopril (1.3 μg/ml) respectively. Cytopathic effect (CPE), cardiac troponin I ( cTnI) , the SERCA activity and mRNA level of the SERCA type 2 were observed after 96 hours. Results: The CPE and cTnI of model group were significantly higher than those of normal, Astragaloside and Perindopril groups ( P <0.01). The activity and the mRNA expression of myocardial SERCA of model group were significantly lower than those of normal, Astragaloside and Perindopril groups ( P <0.01-0.05). Compared with Astragaloside group, the CPE, cTnI of Perindopril group were higher and the activity and mRNA level of Perindopril group were lower. But there were no significant difference between the two groups ( P >0.05). Conclusion: Astragaloside and Perindopril were able to reverse the down regulations of cardiac SERCA activity and mRNA expression caused by virus infection to alleviate the cardiomyocyte injury.