番茄红素通过内质网应激对七氟醚麻醉致认知功能障碍大鼠的保护作用

Protective effect of lycopene on rats with cognitive dysfunction induced by sevoflurane anesthesia through endoplasmic reticulum stress

目的探究番茄红素通过内质网应激(ERS)对七氟醚麻醉致认知功能障碍(CD)大鼠的保护作用。方法采用七氟醚麻醉诱导建立大鼠CD模型。将SD大鼠随机分为对照组、模型组及番茄红素低、高剂量(5、10 mg/kg)组和番茄红素+衣霉素(10 mg/kg+100 μg/kg)组, 每组12只。5、10 mg番茄红素溶解于1、2 ml羧甲基纤维素钠制备成混悬液;100 μg衣霉素溶解于1 ml 0.1%二甲基亚砜中。番茄红素低、高剂量组分别灌胃番茄红素混悬液1 ml, 番茄红素+衣霉素组灌胃番茄红素混悬液1 ml, 并腹腔注射衣霉素1 ml;假手术组和模型组分别灌胃或腹腔注射等量的生理盐水;番茄红素低、高剂量组腹腔注射等量的生理盐水, 均为1次/d, 共给药6周。采用Morris水迷宫实验测定大鼠认知功能, HE染色观察大鼠海马组织形态变化, TUNEL染色观察大鼠海马组织神经元凋亡情况, 酶联免疫吸附试验法检测大鼠海马组织脑源性神经营养因子(BDNF)、S100钙化蛋白β(S100β)水平, Western Blot检测大鼠海马组织凋亡相关蛋白B淋巴细胞瘤-2(Bcl-2)、Bcl-2相关X蛋白(Bax)与ERS标志蛋白葡萄糖调节蛋白78(GRP78)、C/EBP同源蛋白(CHOP)、含半胱氨酸的天冬氨酸蛋白水解酶-12(Caspase-12)的水平。结果与模型组比较, 番茄红素5、10 mg/kg组第3、4、5天的逃逸潜伏期、神经元凋亡率、S100β水平、GRP78、CHOP、Caspase-12和Bax表达均减少(均P<0.05), 穿越平台次数、BDNF水平和Bcl-2表达均增加(均P<0.05)。随着番茄红素剂量的增加, 番茄红素10 mg/kg组较番茄红素5 mg/kg组第3、4、5天的逃逸潜伏期、神经元凋亡率、S100β水平、GRP78、CHOP、Caspase-12和Bax表达均减少(均P<0.05), 穿越平台次数、BDNF水平和Bcl-2表达均增加(均P<0.05)。与番茄红素10 mg/kg组比较, 番茄红素+衣霉素组第3、4、5天的逃逸潜伏期、神经元凋亡率、S100β水平、GRP78、CHOP、Caspase-12和Bax表达均增加(均P<0.05), 穿越平台次数、BDNF水平和Bcl-2表达均减少(均P<0.05)。番茄红素干预后CD大鼠的海马组织神经元丢失减少, 排列分布较为紧密有序, 炎性浸润减轻。ERS激活剂衣霉素减弱了番茄红素对七氟醚麻醉致CD大鼠的保护作用。结论番茄红素可能通过抑制ERS对七氟醚麻醉致CD大鼠起到保护作用。

Objective To investigate the protective effect of lycopene on rats with cognitive dysfunction(CD)induced by sevoflurane anesthesia through endoplasmic reticulum stress(ERS).Methods A rat CD model was established using sevoflurane anesthesia induction.SD rats were randomly divided into a sham operation group,model group,low-,high-dose(5 and 10 mg/kg)lycopene groups,and a lycopene+tunicamycin(10 mg/kg+100μg/kg)group,with 12 rats in each group.5 and 10 mg of lycopene was dissolved in 1 ml of sodium carboxymethylcellulose to form a suspension,and 10μg of clindamycin was dissolved in 1 and 2 ml of 0.1%dimethyl sulfoxide.Rats in the low-,high-dose lycopene groups were gavaged with 1 ml of lycopene suspension,respectively,and the rats in the lycopene+tunicamycin group were gavaged with 1 ml of lycopene suspension and received 1 ml intraperitoneal injection of clindamycin.The sham operation group and the model group received an equal amount of saline by gavage or intraperitoneal injection,respectively.The low-,high-dose lycopene groups received an equal amount of saline by intraperitoneal injection,both 1 time/d for 6 weeks.The Morris water maze test was used to determine the cognitive function of rats.HE staining was used to observe the morphological changes of rat hippocampal tissue.TUNEL staining was used to observe the apoptosis of neurons in rat hippocampal tissue.The ELISA method was used to detect the levels of brain-derived neurotrophic factor(BDNF)and S100 calcifying proteinβ(S100β)in hippocampal tissue.Western Blot was used to detect the levels of apoptosis-related proteins in rat hippocampal tissues,including the levels of B-cell lymphoma-2(Bcl-2),Bcl-2 associated X protein(Bax)with ERS marker glucose-regulated protein 78(GRP78),C/EBP homologous protein(CHOP),and cysteinyl aspartate specific proteinase-12(Caspase-12).Results Compared with the model group,the escape latency,neuronal apoptosis rate,S100βlevel,GRP78,CHOP,Caspase-12,and Bax expression were decreased in the low-,high-dose lycopene groups on days 3,4,and 5(all P<0.05),and the number of crossing platforms,BDNF level,and Bcl-2 expression were increased(all P<0.05).With the increase of lycopene dose,the escape latency,neuronal apoptosis rate,S100βlevel,GRP78,CHOP,Caspase-12,and Bax expression were decreased in the high-dose lycopene group compared with the low-dose lycopene group on days 3,4,and 5(all P<0.05),and the number of crossing platforms,BDNF level,and Bcl-2 expression were increased(all P<0.05).Compared with the high-dose lycopene group,the escape latency,neuronal apoptosis rate,S100βlevel,GRP78,CHOP,Caspase-12,and Bax expression were increased in the lycopene+tunicamycin group on days 3,4,and 5(all P<0.05),and the number of crossing platforms,BDNF level,and Bcl-2 expression were decreased(all P<0.05).Hippocampal tissue neuronal loss and the inflammatory infiltration were both reduced in CD rats after lycopene intervention.The ERS activator tunicamycin attenuated the protective effect of lycopene on sevoflurane-induced CD rats.Conclusions Lycopene may play a protective role against CD in rats anesthetized with sevoflurane by inhibiting ERS.