Role of UCP2 Expression after Hepatic Warm Ischemia-Reperfusion in the Rat

Abstract

Background/AimsThe role of uncoupling protein-2 (UCP2) in the liver is currently unclear. Emerging evidence suggests a relationship between UCP2 and oxidative stress. In the present study, we tested the hypothesis that UCP2 expression in the liver might change during warm ischemia-reperfusion (I/R) according to oxidative stress.MethodsWistar rats were subjected to 40 (short ischemia) or 90 (long ischemia) minutes of partial lobar ischemia followed by 4 hours of reperfusion. UCP2 expression in the ischemic and nonischemic lobes was assessed using reverse transcription-polymerase chain reaction and immunohistochemistry. Malondialdehyde concentrations in the liver tissue were also compared.ResultsMalondialdehyde concentrations in the ischemic lobes were significantly higher in the long ischemia group. In the ischemic lobes of the short ischemia group, UCP2 protein expression was induced in hepatocytes, which did not express the protein prior to treatment, and the expression levels were higher than in the long ischemia group. The intralobular distribution of UCP2 seemed to correlate inversely with that of the necrotic area. UCP2 expression was observed, even in nonischemic lobes with similar intralobular heterogeneity.ConclusionsUCP2 was induced in hepatocytes after warm I/R. Although the primitive role of UCP2 expression may be cytoprotective in nature, its actual protective effect in hepatic I/R may be minimal

Importance of Mitochondria in Cardiac Pathologies: Focus on Uncoupling Proteins and Monoamine Oxidases

“…Studies with UCP2 knockout mice show a different picture compared to the brain and heart, as UCP2 seems not to affect hepatic reperfusion [ 90 ]. Similar conclusions were drawn with warm or cold perfusion [ 91 , 92 ]. Increased hepatic expression of UCP2 was found in mice fed with a high-fat diet, steatotic livers, and fat livers [ 93 , 94 , 95 , 96 ].…”

Polyethylene Glycol 35 as a Perfusate Additive for Mitochondrial and Glycocalyx Protection in HOPE Liver Preservation

“…For instance, it might be of interest to assess levels of syndecan and heparan sulphate, which would give us an insight of the status of the GCX in HOPE strategies [63][64][65][66][67][68]. Further, it would be interesting to assess mitochondrial parameters besides ALDH2 [47], such as succinate [77,78], or others that have been recently linked both to lipoperoxidation and energetic levels, such as UCP1 and UCP2 [79][80][81][82][83], which could provide relevant information, especially when steatotic livers are used (Scheme 2). The assessment of these new proposed markers involved in different critical points of different crucial pathways brought together could strengthen the informative value of the most widely used, such as transaminases.…”

UCP2 attenuates apoptosis of tubular epithelial cells in renal ischemia-reperfusion injury

“…UCP1, 3, 4, and 5 are mainly found in brown adipose tissue, skeletal muscle, the brain, and the central nervous system, respectively (26,33,42), whereas UCP2 is widely expressed but especially high in kidney tissue (47). UCP2 is involved in I/R injury of the heart (35,36), liver (7,19,27,38), brain (4,9,21) and small intestine (8). However, whether UCP2 is protective or injurious remains controversial.…”