Ang Ⅱ 对培养新生大鼠心肌成纤维细胞增殖及丝裂素活化蛋白激酶的影响

EFFECT OF ANGIOTENSIN Ⅱ ON THE PROLIFERATION AND MITOGEN ACTIVATED PROTEIN KINASE IN CULTURED NEONATAL RAT CARDIAC FIBROBLAST

本研究目的在于探讨丝裂素活化蛋白激酶（ＭＡＰＫ）是否在ＡｎｇⅡ（１０－８ｍｏｌ／Ｌ）诱导的培养新生大鼠心肌成纤维细胞（ＦＢ）的增殖反应中起重要作用。实验以ＦＢ数目和ＤＮＡ合成速率（３Ｈ－胸腺嘧啶掺入率）为增殖指标，［γ－３２Ｐ］ＡＴＰ掺入法和免疫印迹法分别测定ＦＢＭＡＰＫ的活性和含量，结果发现（１）ＡｎｇⅡ处理ＦＢ２４ｈ后，ＤＮＡ合成速率和细胞数比对照组分别增加６０％和３９％；（２）ＡｎｇⅡ处理ＦＢ５ｍｉｎ后，ＭＡＰＫ活性比对照组增高２０３％；（３）培养新生大鼠ＦＢ含有两个ＭＡＰＫ同型体－ｐ４４ｍａｐｋ和ｐ４２ｍａｐｋ，其中ｐ４４ｍａｐｋ含量高于ｐ４２ｍａｐｋ，分别为总量的５８％和４２％。ＡｎｇⅡ处理５ｍｉｎ后，ＭＡＰＫ蛋白含量（ｐ４４＋ｐ４２〕增高４２９％，其中ｐ４４ｍａｐｋ的增加明显大于ｐ４２ｍａｐｋ的增加，分别比相应对照增高４８６％和３４９％。以上结果表明，ＡｎｇⅡ诱导的ＭＡＰＫ活性和含量的增加，参与了ＦＢ的增殖反应。

This study was designed to determine whether mitogen activated protein kinase (MAPK) activition occurred in response to angiotensin Ⅱ (AngⅡ, 10 -8 mol/L) in cultured neonatal rat cardiac fibroblast (FB) and the role of MAPK activation in AngⅡ induced FB proliferation. Proliferation of FB was assayed with cell number and rate of DNA synthesis ( 3H thymidine incorporation). Activity and content of MAPK were measured by means of [γ 32 P]ATP incorporation and immunoblot respectively. The results showed that (1) After 24 hours treatment of AngⅡ, the rate of DNA synthesis and cell number of cardiac FB were increased by 60% and 39% respectively, (2) 5 minutes following stimulation with AngⅡ, MAPK activity increased by 203%, (3) Immunoblot analysis of MAPK isoforms in this study revealed predominantly p44mapk(58%) with less p42mapk(42%) in neonatal rat cardiac FB. Following stimulation with AngⅡ for 5 minutes, MAPK protein content increased by 429%, in which p44mapk and p42mapk increased by 486% and 349% compared with corresponding control. These results suggest that activation of MAPK play an important role in the AngⅡ induced proliferation response in neonatal rat cardiac FB.