Analysis of the effects of topical renal hypothermia on lung tissue after kidney ischemia and reperfusion in rats

Abstract

PURPOSE:To evaluate whether topical renal hypothermia (TRH) at different levels of temperature has protective effects on lung tissue after renal I/R, through an analysis of organ histology and inflammatory markers in lung tissue. METHODS:Twenty-eight male Wistar rats were randomly allocated across four groups and subjected to renal ischemia at different levels of topical renal temperature: normothermia (no cooling, 37°C), mild hypothermia (26°C), moderate hypothermia (15°C), and deep hypothermia (4°C). To induce I/R, the vessels supplying the left kidney of each animal were clamped for 40 minutes, followed by reperfusion. After four hours, another procedure was performed to harvest the tissues of interest. TNF-α, IL-1β and myeloperoxidase activity were measured in lung tissue. Histological analysis was performed in hematoxylin and eosin-stained lung specimens. RESULTS:Induction of renal I/R under deep topical hypothermia resulted in a significant decrease in lung concentrations of TNF-α compared with normothermic I/R (p<0.05). A trend toward significant correlation was found between lung IL-1β concentration and intensity of hypothermia p=0.055). No difference was found in myeloperoxidase activity or histologic injury between groups. CONCLUSION:Topical renal hypothermia reduces activation of the inflammatory cascade in the lung parenchyma. However, tissueprotective effects were not observed.

Influence of remote ischemic conditioning and tramadol hydrochloride on oxidative stress in kidney ischemia/reperfusion injury in rats

“…Thus, in order to minimize the damage caused by oxidative stress on physiology of the body under ischemia/reperfusion, different therapeutic approaches were used, such as hypothermia 4 , administration of antioxidant substances 5,6 and hypertonic saline solutions 7 .…”

Effects of remote ischemic preconditioning and topical hypothermia in renal ischemia-reperfusion injury in rats

“…The benefit of local hypothermia in renal tissue varies according to temperature, as demonstrated by Santos et al 22 in a study demonstrating that the temperature of 4 o C leads to a lower oxidative activity in renal tissue submitted to IR in Wistar rats compared to that in other degrees of hypothermia. Fiorentini et al 23 also identified that performing local hypothermia during renal IR reduces inflammatory activity in remote organs not involved in the IR (e.g., lung), revealing the systemic benefits of this maneuver.…”

The effect of insulin-loaded linear poly(ethylene glycol)-brush-like poly(L-lysine) block copolymer on renal ischemia/reperfusion-induced lung injury through downregulating hypoxia-inducible factor

“…23 Lung tissue stored at -80°C was thawed and homogenized in a buffer composed of phosphate-buffered saline, 0.5% Triton X-100, and protease inhibitor, pH 7.2. The material was then centrifuged at 3,600 rpm for 15 minutes at 4°C and the supernatant was collected for enzyme-linked immunosorbent assay.…”