CHANGES AND RELATIONSHIP OF PAF AND TNF IN RATS WITH MYOCARDIAL-ISCHEMIA AND REPERFUSION INJURY

IN this study it is reported that: (1) the levels of blood platelet-ac tivating factor and serum tumour necrosis factor significantly increas ed after coronary ligation and reperfusion, compared with sham-ligated controls, in an anaesthetized rat model; (2) compared with vehicle co ntrols, pretreatment with the PAF antagonist BN 50739 (10 mg/kg, i.v.) produced significant decreases in infarct size (from 29.6 +/- 4.0% to 22.4 +/- 2.1%, p < 0.05 after 3 h ligation, and from 28.5 +/- 9.5% to 10.5 +/- 4.5%, p < 0.01 after 4 h reperfusion) and the level of serum TNF (from 10.4 +/- 7.7 U/ml to 3.9 +/- 4.8 U/ml, p < 0.05); and (3) a significant positive correlation was found between the level of blood PAF or serum TNF and infarct size. The present results indicate that PAF and TNF may be important mediators involved in myocardial ischaemi a and reperfusion injury, and that PAF antagonists may exert a protect ive effect on ischaemic or reperfused myocardium by inhibiting the int eraction of PAF and TNF.