实验性脊髓空洞前状态蛋白激酶C的活性变化及意义

Changes of protein kinase C activity in experimental presyrinx state in rabbits

目的探讨蛋白激酶C(PKC)在脊髓空洞前状态中活性变化及其作用。方法用新西兰兔56只制作模型,术后1、3、7、14、21d用光镜、干湿重法观察上颈髓病理学演变、脊髓含水量,应用底物磷酸化法测定胞膜、胞浆PKC活性。结果高岭土组动物于术后第1天脊髓含水量即有明显增加[(68.35±0.70)%],第7天达到高峰[(72.92±0.86)%],持续到第14天,至第21天时稍有缓解[(70.03±0.77)%];组织学观察发现术后3d上颈髓轻度水肿,7～14d水肿达到高峰期,21d略有缓解;胞膜PKC活性术后1d出现增加(5.67±0.26pmol·mg-1·min-1),7～14d达到最高水平(13.27±3.15pmol·mg-1·min-1),21d开始回落(8.85±1.56pmol·mg-1·min-1),胞浆的PKC活性则呈相反趋势。结论脊髓空洞前状态形成中出现PKC移位激活,参与了缺血、缺氧性脊髓水肿的形成。

Objective To investigate the changes of protein kinase C （PKC） activity and its role in the development of presyrinx state in rabbits. Methods Presyrinx state was established in 56 rabbits by intra-cisternal injection of kaolin. At 1, 3, 7, 14, and 21 days after the injection, the water content in the upper cervical spinal cord was measured, its pathological changes observed microscopically and the PKC activity determined with substrate phosphorolysis kinase assay. Results Spinal cord edema occurred in rabbits one day after kaolin injection, with water content of （68.35±0.70）%, which increased to （72.70±0.88）% on day 3, reaching the peak level of （72.92±0.86）% on day 7, followed by gradual decline after 3 weeks [（70.03±0.77）% ]. The membrane PKC activity increased from 5.67±0.26 pmol·mg^-1·min^-1 on day 1 after the injection to reach the peak level on day 7 （13.27±3.15 pmol·mg^-1·min^-1）, which was maintained till day 14 with subsequent decrease to 8.85± 1.56 pmol·mg^-1·min^-1 on day 21. The cytoplasmic PKC activity showed changes of a reverse pattern. Conclusion In rabbits with experimental presyrinx state, PKC translocation and activation is involved in ischemic spinal edema.