Imayasu Masaki, Shimada Shoichi
Department of Anatomy, Nagoya City University Medical School, Nagoya, Japan.
Curr Eye Res. 2003 Sep;27(3):133-41. doi: 10.1076/ceyr.27.3.133.16055.
To investigate the role of mitogen-activated protein kinase (MAPK), such as p44/42 MAPK, p38 MAPK and stress-activated protein kinase (SAPK), in corneal epithelial cells during the wound healing process.
A single non-penetrating incision was produced on rat cornea. Then the corneal wound healing process was observed with an immunocytochemical technique using specific antibodies reacting only with phosphorylated p44/42 MAPK, p38 MAPK or SAPK. Cell lysates of corneal epithelial cells in rabbits stimulated with keratinocyte growth factor (KGF) and hepatocyte growth factor (HGF) were processed for Western blot using antibodies to phosphorylated p44/42 MAPK.
Maximum activation of p44/42 MAPK was observed in wing and basal cells at wounded regions in rat cornea at 1 hour after the incision. Activation of p44/42 MAPK was still detected in all basal and wing cells at wounded regions at up to 24 hours when the incisions were completely closed, and then receded to normal intensity after 7 days. Neither p38 MAPK nor SAPK were activated during the wound healing process. Western blot analysis of cultured corneal epithelial cells in rabbits showed phosphorylation of p44/42 MAPK after 30 minutes in response to KGF and HGF, whereas non-activated p44/42 MAPK was ordinarily detected even at the absence of KGF or HGF.
These results demonstrate that p44/42 MAPK is activated during the corneal wound healing process and suggest that KGF and HGF play an important role in initiation of cell migration and proliferation in the initial wound healing process by activating p44/42 MAPK.
研究丝裂原活化蛋白激酶（MAPK），如p44/42 MAPK、p38 MAPK和应激激活蛋白激酶（SAPK）在角膜上皮细胞伤口愈合过程中的作用。
在大鼠角膜上制作单个非穿透性切口。然后采用免疫细胞化学技术，使用仅与磷酸化的p44/42 MAPK、p38 MAPK或SAPK反应的特异性抗体，观察角膜伤口愈合过程。用角质形成细胞生长因子（KGF）和肝细胞生长因子（HGF）刺激兔角膜上皮细胞的细胞裂解物，使用针对磷酸化p44/42 MAPK的抗体进行蛋白质印迹分析。
在切口后1小时，在大鼠角膜伤口区域的翼状细胞和基底细胞中观察到p44/42 MAPK的最大激活。在切口完全闭合前的24小时内，伤口区域的所有基底细胞和翼状细胞中仍可检测到p44/42 MAPK的激活，7天后恢复到正常强度。在伤口愈合过程中，p38 MAPK和SAPK均未被激活。对兔培养角膜上皮细胞的蛋白质印迹分析显示，在KGF和HGF刺激30分钟后，p44/42 MAPK发生磷酸化，而即使在没有KGF或HGF的情况下，通常也能检测到未激活的p44/42 MAPK。
这些结果表明，p44/42 MAPK在角膜伤口愈合过程中被激活，并提示KGF和HGF通过激活p44/42 MAPK在伤口愈合初始阶段的细胞迁移和增殖启动中发挥重要作用。
