七氟醚和缺氧预适应对乳鼠心肌细胞生存和凋亡的影响

目的 探讨七氟醚预处理和缺氧预处理诱导乳鼠心肌细胞产生预适应的差异。方法 第2代心肌细胞随机分为正常对照组（C组）、缺氧／复氧组（A／R组）、缺氧预适应组（IP组）和七氟醚组（S组），每组均缺氧2h，复氧48h。取复氧1h心肌细胞用电镜观察细胞超微结构变化；分别取复氧0、1、2、24、36和48h的细胞用MTT法测定细胞生存情况、流式细胞仪测定细胞凋亡率。结果 （1）S组和IP组细胞超微改变不明显，未见凋亡细胞；A／R组改变明显，可见凋亡细胞；（2）在各个时点，S组和IP组的细胞生存能力显著低于C组（P＜0．05），显著高于A／R组（P＜0．01），S组和IP组间无显著性差异（P＞0．05）；随着复氧时间的延长，S组和IP组的细胞生存能力有上升的趋势；（3）在各个时点，S组和IP组的细胞凋亡率显著高于C组（P＜0．01），显著低于A／R组（P＜0．01）；S组和IP组间的细胞凋亡率只是在复氧0h和1h处有显著性差异；随着复氧时间的延长，S组和IP组的细胞凋亡率有下降的趋势，A/R组的则逐渐升高；（4）S组和IP 中的细胞生存力和凋亡之间存在着负相关关系。结论 七氟醚预适应和缺氧预适应对缺氧／复氧损伤细胞可产生早期和延迟保护作用，且两者之间的作用相似，提示在体外实验中七氟醚预适应可取代缺氧预适应。

Effects of sevoflurane and anoxia induced preconditioning on survival and apoptosis of neonatal rat cardiac myocytes

Objective To determine the difference between sevoflurane- and anoxic preconditioning in protecting newborn rat heart muscle cells from anoxia-reoxygenation injury. Methods The second generation of primary cultured cardiac myocytes from 2-3d newborn SD rats were randomly divided into 4 groups: control group (C), anoxia/reoxygenation group (A/R) in which cultured cardiac myocytes were exposed to 2h anoxia followed by 48h reoxygenation; anoxic preconditioning group (IP) in which before A/ R the cardiac myocytes were pretreated with 20 min anoxia; sevoflurane preconditioning group (S) in which cardiac myocytes were pretreated with 20 min 2.5% sevoflurane (1.5 MAC) before A/R. Ultrastructure of heart muscles cells was observed 1 h after reoxygenation, Cell survival was determined by MTT rapid colorimetric assay and apoptosis was measured by flow cytometry at 0, 1, 12, 24, 36 and 48 h after reoxygenation. Results (1) In S and IP group there was no significant change in ultrastructure and no apoptosis cell was found, whereas in A/R group the change in ultrastructure was significant , and apoptosis cells were found. (2) The cell survival in group S and group IP was significantly lower than that in group C but significantly higher than that in group A/R. (P < 0.01) . At each study point of reoxygenation, there was no significant difference in survival between group S and group IP(P >0.05) . The survival of cardiac myocytes increased with prolongation of reoxygenation time in group S and group IP. (3) The apoptosis percentage of cells in group S and group IP was significantly higher than that in group C and lower than that in group A/R(F<0.01). With the prolongation of reoxygenation time, the apoptosis percentage was decreasing in group S and group IP but increasing in group A/R. (4) There was a significantly negative correlation between cell survival and apoptosis in group S or group IP. ConclusionsBoth sevoflurane-and anoxia-induced preconditioning can provide early and delayed protection against A/R injury. The protection provided by sevoflurane preconditioning and anoxia preconditioning is similar, suggesting that sevoflurane preconditioning can replace anoxia /ischemia preconditioning in vitro.