Hexarelin对H2 O2 诱导的大鼠胸主动脉内皮细胞损伤的抑制作用及其机制
Hexarelin protects rat thoracic aorta endothelial cells from H2O2-induced damage in vitro
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摘要: 目的: 观察人工合成的生长激素释放肽hexarelin对H
2 O2 诱导的大鼠胸主动脉内皮细胞损伤是否有抑制作用及可能的机制。方法: 体外原代培养的大鼠胸主动脉内皮细胞，随机分为对照组、H2 O2 组及H2 O2 +10-5 mmol/L hexarelin组和H2 O2 +10-7 mmol/L hexarelin组，通过光镜和电镜观察各组细胞的形态学变化。采用MTT比色法检测各组细胞活力的变化；用比色法检测内皮细胞培养上清液中乳酸脱氢酶（LDH）的含量；用硝酸还原酶法检测内皮细胞培养上清液中一氧化氮（NO）的含量。结果: 光镜和电镜观察发现，H2 O2 可以诱导大鼠胸主动脉内皮细胞损伤及凋亡；而Hexarelin能减轻H2O2所诱导的内皮细胞损伤及凋亡。MTT比色法检测发现，H2 O2 能使内皮细胞的活力由(0.39±0.03)下降为(0.23±0.04)(P<0.01)；而1×10-5和1× 10-7 mmol/L hexarelin能减轻H2 O2 对内皮细胞活力的影响，内皮细胞的活力分别由（0.23±0.04）变为（0.30±0.02）和（0.29±0.02）(P<0.01)。H2 O2 能诱导内皮细胞产生LDH，由(31.11±4.97)U/L上升为(157.48±7.33)U/L(P<0.01)；而1×10-5和1×10-7 mmol/L hexarelin能减少LDH的生成，由［(157.48±7.33)U/L下降为(55.12±6.11) U/L和(94.48±4.07) U/L(P<0.01)。另外，H2O2能引起NO生成减少，由（29.38±6.14）μmol/L降为 （17.24±7.51）μmol/L(P<0.01)，而hexarelin能逆转H2O2引起的内皮细胞NO生成的减少，由(17.24±7.51)μmol/L变为(35.95±4.89)μmol/L和(19.73±2.50)μmol/L(P<0.01)。结论: Hexarelin能够抑制H2 O2 所诱导的大鼠胸主动脉内皮细胞的损伤及其凋亡，其机制可能与hexarelin抑制氧化应激反应及促进NO的产生有关。Abstract: AIM: To observe whether hexarelin, a synthetic growth hormone-releasing peptide, protects rat thoracic aorta endothelial cells from H2 O2 -induced damage and to elucidate its mechanism. METHODS: Cultured endothelial cells from rat thoracic aorta were divided randomly into four groups: control group, H2 O2 group, H2 O2 +10-5 mmol/L hexarelin group and H2 O2 +10-7 mmol/L hexarelin group. The morphology of endothelial cells was observed by contrast phase microscope and transmission electron microscope and cell viability was detected by MTT assay. Levels of lactate dehydrogenase (LDH) and nitrogen monoxidum (NO) were measured by supernatant. RESULTS: Contrast phase microscope and transmission electron microscope showed that H2 O2 induced apoptosis of endothelial cells but hexarelin reversed the damage. H2 O2 decreased endothelial cell viability (P<0.01), whereas 1×10-5 mmol/L/1×10-7 mmol/L hexarelin reversed the damage (P<0.01). H2 O2 increased LDH release (P<0.01) but 1×10-5 mmol/L/1×10-7 mmol/L hexarelin decreased the LDH release (P<0.01). Compared with that in control group, H2 O2 caused the reduction of NO (P<0.01), but 1×10-5 mmol/L/1×10-7 mmol/L hexarelin increased the NO. CONCLUSION: Hexarelin protects rat thoracic aorta endothelial cells from H2 O2 -induced damage and apoptosis, possibly through inhibiting the oxidative stress by increasing the NO levels.
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