脊髓缺血损伤后necroptosis的发生及其分子机制研究

Delayed death of neurons in and around the initial injury site triggered by various secondary mechanisms, especially ischemia, is the primary reason for the expansion of lesion and worsening of over-all condition after spinal cord injuries. Thus, inhibition of delayed neuron death is an important strategy for the treatment of spinal cord injuries. Previous research about neuron protection focused mainly on apoptotic cell death. However, anti-apoptotic treatment alone can only provide limited protection against neuron death. Recently, a form of programmed necrotic cell death, namely necroptosis, has been discovered and found to have wide cross-talk with apoptosis. The results of our previous work using rabbit model of ischemia/reperfusion injury and neuron model of glucose-, oxygen-deprivation indicate that necroptosis is involved in the delayed death of neurons, and that caspase inhibitor may induce the conversion of death mode from apoptosis to necroptosis. Based on these results, the present project aims to elucidate the important role of necroptosis in delayed neuron death using both in vivo and in vitro models of ischemic injury, investigate the conversion of cell death mode from apoptosis to necroptosis after caspase inhibition, and explore the possible role of RIP1 and PARP-1 over-activation in such death mode conversion. This research will assist to expand our understanding of spinal cord injury-induced secondary neuron death and provide theoretical and experimental support for the development of new treatment strategies against spinal cord injuries.

脊髓损伤后缺血缺氧等原因引起的继发性神经元大面积丢失是造成伤情加重的重要原因，避免神经元继发性死亡是改善预后的重要策略。既往对脊髓损伤后神经元保护的研究多集中在避免凋亡方面，然而单纯抑制凋亡往往不能减少神经元死亡的发生。Necroptosis是一种新发现的程序性坏死形式，其与凋亡有广泛联系。我们前期研究结果提示necroptosis是脊髓缺血损伤及缺糖缺氧模型中神经元死亡的重要模式，抑制caspase可能会引起神经元死亡模式从凋亡向necroptosis转化。课题组拟在前期工作的基础上，通过体内外实验明确necroptosis在脊髓缺血损伤病理过程中的重要作用，探索抑制caspase凋亡通路后神经元死亡模式的转化，揭示RIP1、PARP-1过度激活及其造成的细胞能量耗竭在该转化中的关键作用，旨在全面阐明脊髓损伤后继发性神经元死亡的发生机理，为寻找新的脊髓损伤治疗途径提供理论基础和科学依据。

脊髓损伤后缺血缺氧等原因引起的继发性神经元大面积丢失是造成伤情加重的重要原因，避免神.经元继发性死亡是改善预后的重要策略。既往对脊髓损伤后神经元保护的研究多集中在避免凋亡方面，然而单纯抑制凋亡往往不能减少神经元死亡的发生。Necroptosis是一种新发现的程序性坏死形式，其与凋亡有广泛联系。我们前期研究结果提示necroptosis是脊髓缺血损伤及缺糖缺氧模型中神经元死亡的重要模式，抑制caspase可能会引起神经元死亡模式从凋亡向necroptosis转化。课题组在前期工作的基础上，首先在兔脊髓缺血损伤模型中观察凋亡和necroptosis的发生情况，随后通过体内外实验研究神经元necroptosis的发生及necroptosis特异性抑制剂Nec-1对神经元缺糖缺氧模型及脊髓缺血损伤的保护作用，探讨氧化应激水平在神经元necroptosis中的改变并通过体内外实验研究抗氧化剂红花黄素对神经元necroptosis及脊髓缺血损伤的保护作用。研究结果证实，necroptosis是脊髓缺血损伤及缺糖缺氧模型中神经元死亡的重要模式，且其特异性抑制剂Nec-1可抑制神经元necroptosis的发生，改善脊髓缺血损伤的预后。而且神经元necroptosis的发生过程中伴随着氧化应激水平的升高，抗氧化剂红花黄色素可抑制缺糖缺氧模型中以及兔脊髓缺血损伤模型中necroptosis的发生。以上研究结果较全面的阐明了脊髓损伤后继发性神经元死亡的发生机理，为寻找新的脊髓损伤治疗途径提供理论基础和科学依据。