摘要目的 观察2,5-己二酮(2,5-HD)诱导大鼠脊髓中神经丝(NF)含量变化,以探讨正己烷中毒性神经病的分子机制.方法 雄性Wistar大鼠70只随机分为0、2、4、8周对照组和2、4、8周染毒组,每组10只.经腹腔注射2,5-DH予染毒组动物,剂量为400 mg/kg,建立正己烷中毒性神经病模型,对照组注射等量的盐水.利用步态评分评价大鼠周围神经病症状的进展,免疫印迹法(Western Blotting)检测脊髓组织高、中和低相对分子质量神经丝(NF-H、NF-M和NF-L)含量的变化.结果 HD染毒2周后,大鼠逐渐出现肌力降低、步态异常、瘫痪等表现,至染毒8周结束时大鼠呈现典型的中毒性周围神经病特征.随着2,5-HD染毒的进行,大鼠脊髓NF含量呈进行性下降.与0周对照组相比,2、4和8周染毒组大鼠脊髓上清中NF-H含最分别下降15.7%、57.0%和58.0%,NF-M含量分别下降36.0%、61.3%和65.2%,NF-L含量分别下降20.8%、43.9%和44.3%,差异均有统计学意义(P<0.01);在脊髓沉淀中,与0周对照组比较,染毒4、8周组NF-H含量分别下降35.6%和43.2%,NF-L含量分别下降26.4%和42.1%,差异均有统计学意义(P<0.01);2、4和8周染毒组大鼠脊髓沉淀中NF-M含量分别下降23.3%、33.9%和63.7%,差异有统计学意义(P<0.01).大鼠脊髓组织中NF-H、NF-M和NF-L含量与步态评分的复相关系数分别为0.8912,0.9282和0.8981,差异均有统计学意义(P<0.01).结论 2,5-HD染毒诱导的脊髓组织中NF亚单位含量下降,可能是正己烷神经毒性的机制之一.

abstractsObjective To investigate the dynamic changes of neurofilament contents in rat's spinal cord induced by 2,5-hexanedione (2,5-HD),and explore the molecular mechanism of n-hexane neuropathy.Methods Male Wistar rats were administered at a dosage of 400 mg/kg/day 2,5-HD for 2,4 and 8 weeks respectively. HD-induced neurological defects were detected and quantified using gait score, and the relative levels of NF-H, NF-M,and NF-L in spinal cords of rats were determined by Western Blotting. Results Exposure to 2,5-HD produced progressive gait abnormalities,which suggested that the rat model of 2,5-HD-induced neurotoxicity was established successfully. Western-Blotting results showed that NFs content in spinal cord demonstrated a progressive decline as the intoxication continued. In the supernatant fraction,compared to the controls, NF-H con-tent decreased by 15.7%, 57.0%,and 58.0% respectively after 2,4, and 8-week treatment with 2,5-HD (P<0.01); accordingly, NF-M decreased by 36.0%, 61.3%, and 65.2% respectively (P<0.01);NF-L decreased by 20.8% ,43.9%, and 44.3% respectively(P<0.01). In the pellet fraction, the contents of NF-H in groups of 4 and 8 weeks' exposure to HD decreased by 35.6% and 43.2% ,respectively (P<0.01),and those of NF-L decreased by 26.4% and 42.1%, respectively (P<0.01) when compared to the control. Furthermore, NF-M contents in groups of 2,4 and 8 weeks' exposure decreased by 23.3%, 33.9%, and 63.7% respectively (P<0.01). The NFs level in spinal cords was highly correlated with gait abnormality of treated rats as the intoxication went on. Multiple correlation coefficients of NF-H, NF-M, and NF-L content with gait score of HD-treated rat were 0.8912,0.9282 and 0.8981 (P<0.01) respectively. Conclusion The declines of N Fs are highly related to neurobehavioral abnormality of 2,5-HD-treated animals, and involved in the development of nhexane neuropathy.