title: Expression of UCP2 in Wistar rats varies according to age and the severity of obesity.
abstract: Obesity, a complex metabolic disorder, is characterized by mitochondrial dysfunction and oxidative stress. Increased expression of uncoupling protein 2 (UCP2) during obesity is an adaptive response to suppress the production of reactive oxygen species. The aims of this study were to compare the expression of UCP2 in diet-induced obese Wistar rats that differed according to age and their severity of obesity, and to compare UCP2 expression in the liver and muscle of these rats. UCP2 messenger RNA and protein expression was increased 4.6-fold (p < 0.0001) and 3.0-fold (p < 0.05), respectively, in the liver of the older and heavier rats. In contrast, UCP2 expression was decreased twofold (p < 0.005) in the muscle of these rats, while UCP3 messenger RNA (mRNA) was increased twofold (p < 0.01). Peroxisome proliferator-activated receptor alpha (PPARα) was similarly increased (3.0-fold, p < 0.05) in the liver of the older and more severe obese rats. Total protein content was increased (2.3-fold, p < 0.0001), while 5' adenosine monophosphate-activated protein kinase (AMPK) activity was decreased (1.3-fold, p = 0.05) in the liver of the older, heavier rats. No difference in total protein content and AMPK expression was observed in the muscle of these rats. This study showed that the expression of UCP2 varies according to age and the severity of obesity and supports the widely held notion that increased UCP2 expression is an adaptive response to increased fatty acid β-oxidation and reactive oxygen species production that occurs during obesity. An understanding of metabolic adaptation is imperative to gain insight into the underlying causes of disease, thus facilitating intervention strategies to combat disease progression.
authors.affiliation: Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa. carmen.pheiffer@mrc.ac.za.
authors.forename: Carmen
authors.initials: C
authors.lastname: Pheiffer
authors.affiliation: Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.
authors.forename: Carvern
authors.initials: C
authors.lastname: Jacobs
authors.affiliation: Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.
authors.forename: Oelfah
authors.initials: O
authors.lastname: Patel
authors.affiliation: Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.
authors.forename: Samira
authors.initials: S
authors.lastname: Ghoor
authors.affiliation: Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.
authors.forename: Christo
authors.initials: C
authors.lastname: Muller
authors.affiliation: Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.
authors.forename: Johan
authors.initials: J
authors.lastname: Louw
mesh_terms: D000367:Age Factors; D000818:Animals; D007473:Ion Channels / Q000378:metabolism*; D008297:Male; D024101:Mitochondrial Proteins / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D000071246:Uncoupling Protein 2
chemical_list: D007473:Ion Channels; D024101:Mitochondrial Proteins; C000604391:Ucp2 protein, rat; D000071246:Uncoupling Protein 2
keywords: Gene expression; Metabolic adaptation; Obesity; Protein expression; Uncoupling proteins