Effect of postconditioning with adenosine on myocardial levels of mitogen activated protein kinase p 38 and serum levels of soluble fas-ligand and cardiac enzymes in rats subjected to intermittent coronary ischemia

Several research works have been done on the last two decades to limit the damaging effect of ischemic episodes of the heart. Brief cycles of coronary artery reperfusion alternating with re-occlusion applied during the first few minutes of reperfusion, reduce irreversible post ischemic injury vice infarct size, endothelial dysfunctions, apoptosis and was termed post conditioning [postC]. It was reported that administration of some potent compounds at the start of reperfusion could protect the heart against injury and one of these is adenosine. The present study was performed to assess the effect of postC with adenosine on the degree of apoptosis among rats subjected to intermittent coronary ischemia. The present study was conducted on 30 male albino rats that were divided into 3 groups [n10]:-Group 1 consisted of normal healthy rats served as control group and they were sham operated. Group2 consisted of rats that undergone coronary ischemia/reperfusion [PR] by3O minutes occlusion of left anterior descending [LAD] artery. Group3 consisted of rats that received adenosine in a dose 200 pg per minute by i.v infusion for 15 minutes after induction of ischemia. Then, postC procedure was done by 3 cycles of 30 seconds reperfusion and 30 seconds re-occlusion of LAD artery that started immediately after the initial reperfusion. The following parameters were estimated in the rats of all groups: myocardial levels of both mitogen activated protein kinase p.38 [MAP kinase p38] and caspase 3 as well as the serum levels of lactate dehydrogenase [LDH], creatine kinase [CK] and soluble Fas-ligand [sFas-L]. The Findings of the present study revealed that exposure of the myocardium to 30 minutes of ischemia followed by 3 hours of reperfusion was associated with increased levels of the markers of myocardial necrosis vice LDH and CK. In addition apoptosis was stimulated as evidenced by increased serum soluble Fas-L and increased myocardial tissue levels of Caspase-3 and the death kinase MAP kinase P38. Treatment of rats in group 3 with adenosine and postC was associated with decreased LDH and CK levels Furthermore, the apoptotic cell loss was also attenuated as evidenced by decreased myocardial caspase-3 and MAP kinase p38 in the treated group. So, postC was reported to delay the wash out of endogenous adenosine and administration of exogenous adenosine was thought to cause myocardial protection by preservation of ATP, improved nucleotide repletion on perfusion, stimulation of glycolysis and limiting myocardial oxygen demand. It was concluded that adenosine and postC technique could be used as an important clinical therapeutic option to attenuate myocardial apoptosis which could decrease the subsequent myocardial dysfunction and heart failure. But further preclinical and clinical studies on human patients are still needed to test this therapeutic approach

Antemortem and postmortem estimation of skin wound age in rats: biochemical study

Inflammatory mediators play an important role in the mediation of inflammation and trauma. There for they could be usefulfor the determination of vitality and wound age. In the present study, interleukin-6 [IL-6], fibronectin [Fn] and lipoxinA[4] [LXA[4]] were estimated in extracts of antemortem skin wounds in rats. Moreover, we extended our measurements to include the levels of these mediators in rat skin wounds in the early postmortem period aiming to test for their practical usefulness in the estimation of wound vitality and the duration after its infliction. Thirty two rats were divided into 4 groups of rats [8 animals in each group] and were assigned for collection of wound samples at the indicated time intervals. The wound samples were taken 30 mm [group I], 3 hours [group II], 6 hours [group III] and 24 [group IV] hours after infliction of the incised wounds. The specimens as control group were excised from uninjured rats [8 animals] in the same region as wounded groufrs. The rats in group IV were sacrificed by cervical dislocation and kept at room temperature to be used in assessment of postmortem changes on different parameters. Postmortem wound samples were then collected 24 hours after sacrifice of group IV rats and the postmortem control samples were taken from intact skin of the same rats. A special group of rats [n-8] was used to explore the influence of supravital injuries on mediator release from postmortem inflicted wounds. All wound and control specimens were homogenated and assayed for the level of IL. 6, Fn and LXA[4] using quantitative ELISA analysis. Analysis of the changes of the studied parameters in different times revealed that Fn is the first mediator to increase, in 30 mm, after wound infliction. In the following 3 and 6 hours after wounding both Fn and IL-6 were increased. At 24 hours of wounding LXA[4] increases to join Fn and IL-6, at that time Fn and IL-6 were still high. This pattern of increased level of the three mediators was maintained for at least 24 hours postmortem. We can conclude that the combined assay of IL-6, Fn and LXA[4] may be a useful tool in determination of the probable duration lapsed since antemortem wound inflection. Moreover, this pattern of time dependent increase of the three parameters may be also useful in age determination of multiple inflicted wounds at variable intervals in the same victim. We can also conclude that vital reactions are essential for release of the assayed parameters. This can be documented by the lack of significant increase of these parameters in postmortem-inflicted wounds