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目的:评价低温对小鼠N2a细胞氧糖剥夺/复氧复糖时内质网-线粒体结构偶联(MAMs)的影响。方法:将生长状态良好的小鼠N2a细胞采用随机数字表法分为5组(n n＝24)：对照组(C组)、氧糖剥夺/复氧复糖组(OGD/R组)、低温组(H组)、siRNA-Mfn2转染＋低温组(siMfn2＋H组)和siRNA-NC转染＋低温组(siNC＋H组)。C组在正常条件下培养；OGD/R组氧糖剥夺3 h后复氧复糖24 h；H组氧糖剥夺3 h后，在32 ℃低温下复氧复糖24 h；siMfn2＋H组和siNC＋H组模型制备前48 h时分别转染siRNA-Mfn2及非特异性siRNA，余同H组。于复氧复糖24 h时，采用CCK-8法检测细胞存活率，qRT-PCR法检测Mfn2 mRNA表达水平，Western blot检测Mfn2表达水平，透射电镜下观察并测量内质网-线粒体偶联部分长度、内质网周长和线粒体周长，计算内质网-线粒体偶联部分长度/内质网周长比值和内质网-线粒体偶联部分长度/线粒体周长比值，反映MAMs水平。n 结果:与C组比较，其余4组细胞存活率、Mfn2及其mRNA表达水平和MAMs水平降低(n P<0.05)；与OGD/R组比较，H组和siNC＋H组细胞存活率、Mfn2及其mRNA表达水平和MAMs水平升高(n P0.05)；与H组比较，siMfn2＋H组细胞存活率、Mfn2及其mRNA表达水平和MAMs水平降低(n P0.05)。n 结论:低温减轻小鼠N2a细胞氧糖剥夺/复氧复糖损伤的机制与上调Mfn2表达，从而稳定MAMs有关。“,”Objective:To evaluate the effect of hypothermia on the mitochondria-associated endoplasmic reticulum membranes (MAMs) during oxygen-glucose deprivation and reoxygenation (OGD/R) in the mouse neuroblastoma cells (N2a).Methods:The well-growing N2a cells were divided into 5 groups (n n=24 each) using a random number table method: control group (group C), group OGD/R, hypothermia group (group H), transfection with siRNA-Mfn2 plus hypothermia group (group siMfn2+ H), and transfection with siRNA-NC plus hypothermia group (group siNC+ H). The cells were cultured in normal condition in group C. The cells were subjected to On 2-glucose deprivation (OGD) for 3 h followed by restoration of On 2-glucose supply for 24 h in group OGD/R.The cells were subjected to OGD for 3 h followed by restoration of On 2-glucose supply for 24 h at 32 ℃ in group H. In siMfn2+ H and siNC+ H groups, cells were transfected with siMfn2 and non-specific interfering RNA, respectively, at 48 h before establishing OGD/R model, and the other treatments were similar to those previously described in group H. At 24 h of reoxygenation, cell survival rate was recorded by the cell counting kit-8 assay, the expression of mitofusin 2 (Mfn2) mRNA and protein was detected by quantitative real-time-polymerase chain reaction or Western blot, and the length of the coupling structure, endoplasmic reticulum perimeter and mitochondrial perimeter were observed and measured with a transmission electron microscope.The ratio of the length of the coupling structure/endoplasmic reticulum perimeter and ratio of the length of the coupling structure/mitochondrial perimeter were calculated to reflect the level of MAMs.n Results:Compared with group C, the cell survival rate and level of MAMs were significantly decreased, and the expression of Mfn2 protein and mRNA was down-regulated in the other four groups (n P<0.05). Compared with group OGD/R, the cell survival rate and level of MAMs were significantly increased, and the expression of Mfn2 protein and mRNA was up-regulated in H and siNC+ H groups (n P0.05). Compared with group H, the cell survival rate and level of MAMs were significantly decreased, and the expression of Mfn2 protein and mRNA was down-regulated in group siMfn2+ H (n P0.05).n Conclusion:The mechanism by which hypothermia attenuates OGD/R injury is associated with up-regulating the expression of Mfn2, and thus making MAMs stable in N2a cells of mice.