Abstract:

Objective To investigate myocardial damage, the alterations of plasma, and myocardial angiotensin Ò and myocardial AT₁ receptor as well as the effects of bisoprolol after brain injury in rats. Methods Brain injury was induced by weight-drop technique and pretreated with bisoprolol. Plasma angiotensinÒ level was determined using RIA. Myocardial angiotensinÒand AT₁ receptor were detected by immunohistochemical method. Myocardium-type creatine kinase isoenzyme (CK-MB) was measured. The morphologic changes of myocardium were observed with light and electronic microscope. Results Plasma angiotensin Ò and serum CK-MB increased at 24 h after brain injury. AngiotensinÒ and AT₁ receptor in myocardium also increased. Degeneration and necrosis of myocardium were detected with light and electronic microscope, which included increasing and swelling of mitochondria and disruption of cardiac muscle fiber. Plasma angiotensin Ò and serum CK-MB decreased in bisoprolol group compared with brain injury group. Relief of myocardial damage was also observed with light and electronic microscope in bisoprolol group. Conclusion Brain injury can lead to myocardial damage. RAS maybe plays an important role in the mechanism of myocardial damage after brain injury. Bisoprolol can prevent myocardial damage after brain injury.

Key words: brain injury, myocardial damage, AngÒ, AT₁ receptor, bisoprolol