脑创伤组织提取液的神经营养活性及其活性因子来源的探讨

NEUROTROPHIC ACTIVITY IN BRAIN WOUND TISSUE EXTRACT AND THE ORIGIN OF THE ACTIVE FACTORS

切除成年大鼠大脑双侧顶叶部分皮质,在术后不同时间取损伤周围脑组织,制成脑创伤组织提取液(BWTE);并建立新生大鼠大脑皮质神经元体外培养模型,检测BWTE中的神经元营养因子(NTFs)和促神经突起生长因子(NPFs)。为探讨这些因子的来源,是否与脑创伤区早期出现大量的巨噬细胞有关,我们培养巨噬细胞,收集巨噬细胞条件性培养基(MφCM),检测MφCM对大脑皮质神经元的神经营养活性。此外,亦观察BWTE和MφCM对PC 12细胞的作用,以进一步探讨NPFs的作用机制。实验结果表明,BWTE和MφCM中含有对大脑皮质神经元的NTFs和NPFs。这些因子于脑损伤后第4天开始出现,第5天达高峰(NPFs在第9天还出现一个高峰),第13天仍有活性。MφCM的NTF活性不及BWTE,但NPF活性则比BWTE强。BWTE和MφCM对PC 12细胞也具有NPF活性。通过实验分析认为,BWTE中的神经营养因子,早期主要来源于巨噬细胞,后期可能与星形胶质细胞有关。这些因子成分复杂,可能含多种有效成分,有待今后进一步探讨。

Bilateral ablation of the cerebral parietal cortex in adult rats was performed. After appropriate days, the tissue surrounding the wound was removed and the brain wound tissue extract (EWTE) was prepared. Newborn rat cerebral cortical neurons were used as a culture model to test the neuronotrophic factors (NTFs) and neuritepromoting factors (NPFs) in EWTE. In order to investigate the origin of above mentioned factors whether related to the macrophages which appeared in the brain wound region at early stage, we designed to culture macrophages and collected the macrophage conditioned medium (MφCM) to measure their NTF and NPF activities for cultured cerebral cortical neurons. On the other hand, we also observed the effect of EWTE and MφCM on PC 12 (phehrmytema) cells and further studied the action of NPFs. Cur experimental results show that EWTE and MφCM contained NTFs and NPFs for cultured cerebral cortical neurons. These factors appeared in EWTE at 4 days post-lesion, with maximal level of their activities reached between 5 and 6 days post-lesion and there was another peak of NPF activity at 9 days post-lesion, until 13 days post-lesion also detected their activities. The NTF activity in MφCM was lower than that in BWTE, in contrast, the NPF activity in MφCM was higher than that in BWTE. There was NPF activity to PC 12 cells in BWTE and MφCM. According to the experimental assays, we suppose that the neurotrophic factors in BWTE mainly come from the macrophages which appear in the lesion site at early stage of injured brain, subsequently, it may relate to the astrocytes. The components of these factors may be complexity and multiplicity that remain to be solved.