体外培养大鼠星形胶质细胞受损后的激活与反应性胶质化

ACTIVATION OF PRIMARILY CULTURED RAT ASTROCYTES AFTER INJURY AND REACTIVE ASTROGLIOSIS

用鼠脑星形胶质细胞（ＡＳ）原代培养技术建立体外ＡＳ机械性损伤模型。以ｃ—Ｆｏｘｓ、ｂＦＧＦ、ＰＣＮＡ、ＧＦＡＰ—ｍＲＮＡ、ＧＦＡＰ和Ｍｙｏｓｉｎ作为观察指标研究反应性星形胶质化的形成机制。结果显示：１．ｃ—Ｆｏｓ蛋白于损伤后４５ｍｉｎ即有阳性表达，伤后２ｈ消失；２．损伤后２ｈ，损伤边缘的ＡＳ开始表达ｂＦＧＦ，１２ｈ达高峰，２ｄ后表达强度开始回落；３．损伤边缘的部分ＡＳ于损伤后２ｈ开始表达ＰＣＮＡ，伤后１ｄ，ＰＣＮＡ阳性的ＡＳ沿损伤边缘呈列兵式整齐排列，２ｄ后ＰＣＮＡ阳性的ＡＳ分布于损伤周围区域；４．损伤后４ｈ，损伤边缘的ＡＳ开始表达Ｍｙｏｓｉｎ，并逐渐增加，而且朝向损伤区胞浆突起的阳性表达强于背向损伤区的突起；５．损伤边缘的ＡＳ于损伤后６ｈ开始表达ＧＦＡＰ—ｍＲＮＡ，１ｄ达高峰，２ｄ开始回落，３ｄ则只在少数ＡＳ中可检出ＧＦＡＰ—ｍＲＮＡ；６．损伤后１ｄ，ＧＦＡＰ表达明显增强，胞体肥大并向损伤区伸出粗大突起，２ｄＧＦＡＰ达高峰，３ｄ肥大ＡＳ的胞体和突起覆盖损伤区；７．在体外ＡＳ机械性损伤模型上，在没有神经元和其它复杂因素影响的条件下，ＡＳ对损伤的主要反应是胞体的肥大、突起的粗大，并能独立形成反应性星形胶质化。

The dynamic changes of c-Fos protein, bFGF, PCNA, GFAP-mRNA, GFAP and Myosin in reactive astrogliosis were studied on primary astrocyte .culture with mechanical scratch. The results showed as fol lows: 1. c-Fos protein presented in the survived cells near injured area 45 min after insults and disappeared two hours thereafter; 2. bFGF began to be expressed by astrocytes at the edge of the injury two hours after scratch and reached its peak on 12 th hour, then declined after two days; 3. PCNA was expressed by part of astrocytes in the vicinity of the injury, the PCNA positive astrocytic nuclei lined up along the border of the injury after one day and these nuclei were distributed in the environs of the injury two days after injury; 4. myosin began to be ex pressed by astrocytes at the edge of the injury four hours after damage, then enhanced gradually, positive expression of myosin of the cytoplasmiexpres-sion of myosin of the cytoplasmic processes toward the denuded area was stronger than that of processes in theopposite directon; 5. GFAP-mRNA was detectable in astrocytes near the injury six hours after trauma andreached its peak within twenty-four hours, on the third day a few astrocytes in the injured area revealed GFAP-mRNA; 6. Enhanced expression of GFAP was observed with hypertrophy of astrocyte which extended widened processes into the injured area one day after scratch and reached its peak on the second day, on the third day the previously injured area was covered with hypertrophic astrocytes and their processes; 7. Under the condi tion free of neuron and other systemic interactions, the major responses of astrocytes in the scratch-wound mod el to injury were hypertrophy of cell bodies and cytoplasmic processes, and astrogliosis can be formed by astrocytes independently. The results suggested that 1. proto oncogene c-fos was rapidly and transiently acti vated, and its proteins might in turn modulate the activation of the injured astrocytes; 2. the autocrine of bFGF was the early respone of reactive astrocytes and bFGF might act as promotor of the astrocytic reaction;3. astrocytes can express positive myosin after injury, facilitating the outgrowth and movement of the cellular processes; 4. enhanced GFAP expression was the result of upregulation of GFAP-mRNA; 5. reactive astrogliosis was the innate characteristic of astrocytes themselves and the prominent event of astrogliosis was hypertrophy of astrocytes, a few astrocytes proliferated expressing positive PCNA.