In vivo pressure-flow curve in unilateral rat lung ischemia-reperfusion injury

Inflammatory response to pulmonary ischemia-reperfusion injury

Lung ischemia-reperfusion (IR) injury is one of the most important complications following lung transplant and cardiopulmonary bypass. The pulmonary dysfunction following lung IR has been well documented. Recent studies have shown that ischemia and reperfusion of the lung may each play significant yet differing roles in inducing lung injury. The mechanisms of injury involving neutrophil activation, and the release of numerous inflammatory mediators and oxygen radicals also contributes to lung cellular injury, pneumocyte necrosis, and apoptosis. We herein review the current understanding of the underlying mechanism involved in lung IR injury. The biomolecular mechanisms and interactions which lead to the inflammatory response, pneumocyte necrosis, and apoptosis following lung IR therefore warrant further investigation.

Chronic hypoxia attenuates ischemia-reperfusion-induced increase in pulmonary vascular resistance

This study explored the effect of chronic hypoxia on the elevation of pulmonary vascular resistance caused by ischemia-reperfusion (IR) in anesthetized rats. Experiments were separated into five parts. In Part 1, we examined the increase in left pulmonary vascular resistance (Rpl) after ischemia of the left lung and localized the major site for the increased resistance of the left pulmonary vasculature in both the normoxic and chronic hypoxia groups. Here, IR induced a significant increase in Rpl in the normoxic but not the chronic hypoxia group. This increased Rpl in the normoxic group was attributed to contraction of pulmonary arterial segments. Part 2 and Part 3 were focused on the changes in plasma nitrate/nitrite (NOx) and thromboxane B(2) (TxB(2)) levels. TxB(2) increased significantly in the normoxic group, whereas NOx increased significantly in the chronic hypoxia group, following ischemia. Indomethacin (Part 4) prevented IR-induced increase in Rpl in the normoxic group, whereas the IR-induced increase in Rpl appeared in the chronic hypoxia group after N(G)-nitro-L-arginine methyl ester treatment (Part 5). We conclude that IR elicited increases in the cyclooxygenase products such as TxB(2), which in turn caused an increase in Rpl. However, this increased Rpl was attenuated by elevated NOx in the chronic hypoxia group.

Fullerene derivative attenuates ischemia-reperfusion-induced lung injury

Reactive oxygen species are the major contributing factors to lung ischemia-reperfusion (IR) injury. In this study, we tested whether a water soluble antioxidant fullerene derivative [C(60)(ONO(2))(7 +/- 2)] attenuates IR lung injury. Young Wistar rats were divided into two groups: control and C(60)(ONO(2))(7 +/- 2). Under ventilation with 95% air-5% CO(2) gas mixture and a 2.5 cm H(2)O end-expiratory pressure, the isolated lungs were perfused with a physiological solution. The experimental protocol included three periods: baseline (10 min), ischemia (45 min) and reperfusion (60 min, ventilated with 95% O(2)-5% CO(2) gas mixture). Before and after ischemia, we measured pulmonary arterial pressure (Ppa), pulmonary venous pressure and lung weight (W). Then, pulmonary capillary pressure and filtration coefficient (K(fc)) were calculated. Ischemia caused increases in Ppa, W and K(fc) in the control group. For most cases, the above ischemia-induced increases were attenuated by the C(60)(ONO(2))(7 +/- 2) pretreatment. Our results suggest that the antioxidant C(60)(ONO(2))(7 +/- 2) attenuates IR-induced lung injury.