Preconditioning-Like Properties of Short-Term Hypothermia in Isolated Perfused Rat Liver (IPRL) System.

Norma Alva,Jesús Palomeque,Teresa Carbonell,Raquel Bardallo,David Basanta

doi:10.3390/ijms19041023

Norma Alva, Jesús Palomeque + Show 3 more

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https://doi.org/10.3390/ijms19041023

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Abstract

Hypothermia may attenuate the progression of ischemia-induced damage in liver. Here, we determined the effects of a brief cycle of hypothermic preconditioning applied before an ischemic/reperfusion (I/R) episode in isolated perfused rat liver (IPRL) on tissue damage and oxidative stress. Rats (male, 200–250 g) were anaesthetised with sodium pentobarbital (60 mg·kg−1 i.p) and underwent laparatomy. The liver was removed and perfused in a temperature-regulated non-recirculating system. Livers were randomly divided into two groups (n = 6 each group). In the hypothermia-preconditioned group, livers were perfused with hypothermic buffer (cycle of 10 min at 22 °C plus 10 min at 37 °C) and the other group was perfused at 37 °C. Both groups were then submitted to 40 min of warm ischemia and 20 min of warm reperfusion. The level of tissue-damage indicators (alanine amino transferase, ALT; lactate dehydrogenase, LDH; and proteins), oxidative stress markers (thiobarbituric acid-reactive substances, TBARS; advanced oxidation protein products, AOPP; and glutathione, GSH) were measured in aliquots of perfusate sampled at different time intervals. Histological determinations and oxidative stress biomarkers in homogenized liver (AOPP; TBARS; nitric oxide derivatives, NOx; GSH and glutathione disulphide, GSSG) were also made in the tissue at the end. Results showed that both damage and oxidant indicators significantly decreased while antioxidant increased in hypothermic preconditioned livers. In addition, homogenized liver determinations and histological observations at the end of the protocol corroborate the results in the perfusate, confirming the utility of the perfusate as a non-invasive method. In conclusion, hypothermic preconditioning attenuates oxidative damage and appears to be a promising strategy to protect the liver against IR injury.

Highlights

During liver surgery and transplantation, a serious clinical problem arises: the transient ischemia and reperfusion injury (IRI) [1,2,3]
The level of tissue-damage indicators, oxidative stress markers were measured in aliquots of perfusate sampled at different time intervals
We evaluated some parameters of tissue damage and oxidative stress in the perfusate collected in an isolated perfused rat liver (IPRL) model at different times during preconditioning, ischemia and reperfusion

Summary

Introduction

During liver surgery and transplantation, a serious clinical problem arises: the transient ischemia and reperfusion injury (IRI) [1,2,3]. IRI is a complex damage attributable to various factors. When the donor liver undergoes the process of retrieval surgery followed by cooling storage, energy consumption is reduced. Effects associated with anaerobic metabolism included lactate acidosis [4], proteolysis [5] and sinusoidal endothelial damage [3] among others. Grafts are exposed to reperfusion, normothermia and oxygenation, a process that triggers the release of reactive oxygen species (ROS) and inflammatory mediators [3,6]. Due to the wide diversity of mechanisms involved in IRI, many therapeutic mechanisms have been suggested to prevent hepatic damage [7]. Pharmacological interventions [2,8,9,10] and the different preconditioning mechanisms are the most common strategies [11,12,13]

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Conclusion