脊髓组织胍丁胺含量的测定及脊髓损伤后内源性胍丁胺含量的变化

Concentration of endogenous agmatine in normal and injured spinal cord:experiment with rats

目的测定大鼠脊髓损伤前后内源性胍丁胺的浓度。方法 SD 大鼠42只,随机分为假手术组和损伤后1、4、8、24、48、72h 组。采用改良 Allen’s打击法建立大鼠脊髓损伤实验模型。将各时段损伤部位的脊髓组织 OPA-MCE 柱前衍生处理后,行高效液相色谱分析及荧光检测,并以外标法计算样品浓度。结果损伤前大鼠脊髓组织内源性胍丁胺含量为(0.64±0.11)μg/g;脊髓损伤后1h,胍丁胺浓度轻度下降,损伤后4h 胍丁胺浓度开始升高,8～24h 达到高峰,以后逐渐回落,至3d 时已接近正常水平。结论哺乳动物中枢神经系统中胍丁胺浓度的大致范围应在0.2～1.1μg/g之间。脊髓损伤后内源性胍丁胺浓度虽有明显升高,但尚未达到离体实验中阻断 N-甲基-D 门冬氨酸受体和抑制一氧化氮合酶活性的有效浓度,从而也就难以发挥其神经功能保护效应。

Objective To detect the concentration of endogenous agmatine in normal and injured rats＇ spinal cord. Methods Forty-two SD rats were randomized to sham-operation group and 1 hour, 4 hours, 8 hours, 24 hours, 48 hours, 72 hours after operation groups. The modified Allen＇s model of spinal cord injury was established. The endogenous agmatine was detected both in normal and injured rats＇ spinal cord by high-rerformance liquid chromatography （HPLC） with flurorescence detection and OPA derivatization. Results The endogenous agmatine level in naive rats＇ spinal cord were （0. 643 ± 0. 111 ） μg/g wet weight. After spinal cord injury, the concentration had a transient drop followed by significantly increase, and then decreased by degrees. Conclusion Up to now, little has been known about the endogenous agmatine levels in mammalian tissues. The results reported by different authors varied up to hundred times. According to our results and other articles, the endogenous agmatine levels in mammals＇ central nervous system arranged from 0. 2 μg/g to 1.1 μg/g wet weight. Although there was a significant increase after spinal cord injury, the peak concentration was extremely lower than what it needed to take its neuroprotective effect in vitro.