蛋白激酶C对Bcl-2、Bax调控兔脊髓空洞前状态神经元凋亡的影响

Effect of PKC on neuronal apoptosis regulated by Bcl-2 and Bax in experimental presyrinx state

目的探讨蛋白激酶C(PKC)对Bcl-2、Bax调控兔脊髓空洞前状态神经元凋亡的影响。方法用成年新西兰白兔制作模型,术后1、3、7、14、21 d,用底物磷酸化法测定胞膜、胞质PKC活性;用TUNEL法和免疫组化检测脊髓神经元凋亡和Bcl-2、Bax表达。结果 Kaolin组动物胞膜PKC活性术后1 d出现增加〔(5.67±0.26)pmol.mg-1.min-1〕,7～14 d达到最高水平〔(13.27±3.15)pmol.mg-1.min-1〕,21 d开始回落〔(8.85±1.56)pmol.mg-1.min-1〕,胞质的PKC活性则呈相反趋势;同时受试动物术后各个时点上颈髓均有神经元凋亡发生,以7～14 d最为多见〔(37.75±4.36)%〕;Bcl-2和Bax表达均于术后1 d开始增加〔(7.50±1.15)%;(18.27±2.55)%〕,到术后7 d达高峰〔(17.64±4.52)%;(40.29±3.68)%〕,持续至14 d后下降。但后者明显强于前者。结论脊髓空洞前状态发展过程中,出现了PKC的转位激活,其通过直接或间接途径上调Bcl-2和Bax表达,主要上调Bax,诱导神经元凋亡,参与了神经功能损害。

Objective To investigate mechanism of PKC on neuronal apoptosis regulated by Bcl-2 and Bax in presyrinx state of rabbits.Methods The experimental models of rabbits were established by intra-cisternal injection of kaolin.PKC activity,neuronal apoptosis and the expression of Bcl-2,Bax were measured by substrate phosphorolysis kinase assay,TUNEL and immunohistochemistry in 1,3,7,14,21 d after operation respectively.Results In kaolin group,membrane PKC activity was increased from 1st day（（5.67±0.26） pmol·mg-1·min-1）,reached its peak at 7th day,lasted to 14th day（（13.27±3.15） pmol·mg-1·min-1）,and then began to drop（（8.85±1.56）pmol·mg-1·min-1）,Kytoplasm PKC activity showed opposite tendency;neuronal apoptosis was observed at all time points,but were the most in 7～14th day（37.75%±4.36%）;Bcl-2 and Bax expressions were increased from 1st day（7.50%±1.15%;18.27%±2.55%）,reached its peak at 7th day（17.64%±4.52%;40.29%±3.68%）,lasted to 14th day,and then began to drop.Although Bax expression had the similar trendency to Bcl-2,the former was much stronger than the latter.Conclusions In the development of experimental presyrinx state,translocational activation of PKC directly or indirectly upregulates Bcl-2 and Bax expressions,especially upregulates the latter,inducing neuronal apoptosis to involve in nervous function injury.