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

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.

Novel Targets for Treating Ischemia-Reperfusion Injury in the Liver

“…De Almeida et al illuminated that hepatic preconditioning ameliorated liver IRI by reducing lipid peroxidation [ 15 ]. In addition, hypothermic preconditioning, remote ischemic preconditioning (RIPC), and pharmacological pretreatment with statins are a benefit to IRI [ 16 , 17 , 18 ]. Although ischemic preconditioning protects organs against IRI, the ischemic preconditioning time is very critical.…”

Analysis of Association between Intake of Red Wine Polyphenols and Oxidative Stress Parameters in the Liver of Growing Male Rats

“…The other important limitation results from a sample size which was sufficient for animal model study, but requires to be reproduced in a larger studies and also in a different models (including experiments for different red wines). The other issue is associated with the applied research methodology and tissue preparation, as some recent studies indicate that not only mild to moderate hypothermia should be applied, but also perfusion should be included to maintain hepatic viability and reduce oxidative stress which may influence TBARS results [90][91][92] and it is applied in some studies [93]. However, in a number of other studies, such perfusion is not applied and liver is proceeded immediately and in hypothermia only, to reduce oxidative stress and resultant changes [94][95][96] and such approach was chosen also for the presented study.…”

Nrf2 and oxidative stress in liver ischemia/reperfusion injury

“…Among the therapeutic measures that have been developed with the aim of protecting the liver from I/ R injury, we have highlighted the usefulness of hypothermic preconditioning [4]. Treatment with mild hypothermia against cerebral IR promoted the nuclear localization of Nrf2, and increased the levels of NQO and HO-1 reducing oxidative stress and mitochondrial dysfunction [129].…”

“…Subsequently, Kupffer cells and neutrophils are recruited in response to the death of hepatocytes, leading to liver inflammation. Under the IR process, the damage caused to the liver tissue causes the nonviability of the organ [4].…”