抗艾滋性认知功能障碍的中、西药NMDA拮抗剂效果差异的比较、筛选及临床前研究

HIV-1-associated neurocognitive disorders(HAND) is an important AIDS complication.Our previous studies found that: NR2B subtype of NMDA receptor plays a key role in the pathogenesis of HAND. NR2BR is expected to become a new target for drug therapy. And we found that the total saponins of panax notoginseng (PNS) can improve cognitive function from the synaptic level, PNS can also block the NMDAR mediated Ca2+ influx. Because the severe side effects limit the clinical application of modern NMDAR antagonists, traditional Chinese medicine with high efficiency and low toxicity has been paid more and more attention and become the international research hotspot. We think the target of PNS to improve cognitive function is in accordance with the recent studies for mechanism of HAND, and has development as a potential medicine for HAND. Based on our previous observations we intend to further characterize the role that extrasynaptic NR2BR might play in MCP-1 induced HAND and the effects of PNS on NMDAR, especially on NR2BR in Xenopus oocytes, rat hippocampal brain slices, and cultured hippocampal neurons. In our research work the patch clamp, gene transcription, protein expression, [Ca2+]i dynamic scanning, RealTime-PCR, and other technology may be used to uncover whether the improving effect of PNS on cognitive function is related to its blocking effect on NMDAR, especially on extrasynaptic NR2BR. At the same time, we intend to use the recognized modern NMDAR antagonist ifenprodil and memantine as the positive medicine to compare the differences between PNS and Hesperian medicine, and identify whether PNS has obvious superiority compared with Hesperian medicine.

艾滋性认知功能障碍(HAND)是重要艾滋病并发症。我们的前期研究发现:以NR2BR为主的NMDAR在HAND发生过程中起重要作用,有望成为药物治疗新靶点;还发现三七总皂苷PNS可阻断NMDAR介导的钙内流和兴奋性突触后电流,并能改善认知功能。因西药NMDAR拮抗剂临床应用的局限性,使高效低毒的中药日益受到重视渐成为国内外研究热点。我们认为PNS改善认知功能的机制和靶点符合现代医学对HAND发病机理的认识, 具有开发潜力,因此,拟在前期研究基础上,运用膜片钳、基因转录及蛋白表达、[Ca2+]i动态扫描、RT-PCR等技术,继续研究并筛选PNS及其主要单体成分改善认知功能作用是否通过阻断NMDAR尤其是突触外NR2BR介导,同时以拮抗NMDAR的西药抗痴呆药ifenprodil和美金刚为阳性药,比较它们的差异以确定中药的作用效果,从而更深层次认识HAND发生机制,为治疗HAND提供更多选择。

艾滋性认知功能障碍(HAND)是艾滋病重要的并发症。我们的前期研究发现:以NR2BR为主的NMDAR在HAND发生过程中起重要作用,有望成为药物治疗新靶点。在此基础上，我们比较研究了三种中药与西药NMDAR阻断剂对HAND大鼠的保护作用，分别是三七总皂苷（PNS）、丹参酮IIA（Tan IIA）、柚皮苷三种中药和西药NMDAR阻断剂美金刚、NR2BR阻断剂Ifenprodil。首先，为了确定PNS是否通过阻断NMDAR来减弱CCL2介导的神经毒性，我们检测了PNS对NR2AR和NR2BR介导电流的影响，发现PNS显著降低了此2种电流的振幅,提示PNS的神经保护作用可能与NMDAR抑制有关；我们发现PNS、美金刚和Ifenprodil可以改善CCL2诱导的认知障碍。PNS以剂量依赖方式减轻CCL2诱导的学习记忆障碍，与美金刚相比，200 mg/kgPNS具有更强的神经保护作用,且200 mg/kgPNS具有与Ifenprodil相似的作用。PNS可以改善CCL2引起的谷氨酸代谢紊乱,防止NMDAR过度激活引起的氧化应激,防止CCL2引起的随后的炎症和凋亡。研究过程中我们发现另外两个药物：丹参酮IIA和柚皮苷在HAND大鼠模型上也发挥了提升学习记忆力的作用，也具有一定的开发潜力，但以前文献未见报道。我们发现丹参酮 IIA可以参与氧化应激反应改善由CCL2造成的大鼠海马神经细胞损伤,通过减少海马组织内IL-1β、IL-6炎症因子而调节炎症反应,还通过调控凋亡因子Caspase-3、Caspase-8、Caspase-9从而减少细胞凋亡,保护海马神经细胞。对柚皮苷的研究发现其可通过抗氧化应激、抗炎、抗兴奋性毒性而改善HAND大鼠的学习记忆力。此研究比较上述中西药的差异以确定中药的作用效果,从而为治疗HAND提供更多选择。