抛物线飞行对SH-SY5Y细胞氧化还原状态的影响

Effects of parabolic flight on redox status in SH-SY5Y cells

本研究通过对与氧化还原状态相关指标的免疫细胞化学分析,研究重力变化条件下细胞的氧化应激状态;探讨细胞氧化还原关键分子硫氧还蛋白(thioredoxin,TRX)对重力变化条件下细胞氧化还原状态的影响。采用神经母细胞瘤细胞(SH-SY5Y细胞)作为研究对象,分为4组:地面对照组、转染TRX细胞地面对照组、飞行组、转染TRX细胞飞行组,以免疫细胞化学方法观察抛物线飞行条件下,SH-SY5Y细胞硝基酪氨酸(3-nitrotyrosine,3-NT)、诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)、TRX以及硫氧还蛋白还原酶(thioredoxin reductase,TRXR)表达的变化。结果显示,与地面对照组相比,飞行组抛物线飞行后,3-NT表达水平升高,TRX染色强度略增强,TRXR表达下调;与飞行组相比,转染TRX细胞飞行组iNOS表达下调,3-NT水平降低。上述结果表明,重力变化可以诱导iNOS、3-NT、TRX的表达,下调TRXR的表达,增加SH-SY5Y细胞的氧化应激水平,TRX转染细胞能在一定程度上对抗重力变化引起的氧化应激。

Space flight is known to produce a number of neurological disturbances. The etiology is unknown, but it may involve increased oxidative stress. A line of experimental evidence indicates that space flight may disrupt antioxidant defense system and result in increased oxidative stress. In vitro studies found that abundant of NO was produced in rat pheochromocytoma （PC12） cells, SHSY5Y neuroblastoma cells, and protein nitration was increased in PC 12 cells within a simulated microgravity rotating wall bioreactor high aspect ratio vessel system or clinostat system. In the present study, we observed the change of redox status in SH- SY5Y cells after parabolic flight, and studied the effects of key redox molecule, thioredoxin （TRX）, during the altered gravity. SHSY5Y cells were divided into four groups： control cells, control cells transfected with TRX, flight cells and flight cells transfected with TRX. The expression levels of 3-nitrotyrosine （3-NT）, inducible nitric oxide synthase （iNOS）, TRX and thioredoxin reductase （TRXR） were observed by immunocytochemical method. It was shown that after parabolic flight, the staining of 3-NT and TRX were enhanced, while the expression level of TRXR was down-regulated compared with control. As for flight cells transfected with TRX, the staining of 3-NT and iNOS were weakened compared with flight cells. These results obtained suggest that altered gravity may increase protein nitration, down-regulate TRXR and elicit oxidative stress in SH-SY5Y cells, while TRX transfection could partly protect cells against oxidative stress induced by parabolic flight.