Haptoglobin and the inflammatory and oxidative status in experimental diabetic rats: antioxidant role of haptoglobin
- PDF / 483,712 Bytes
- 14 Pages / 547.087 x 737.008 pts Page_size
- 80 Downloads / 196 Views
ORIGINAL PAPER
Haptoglobin and the inflammatory and oxidative status in experimental diabetic rats: antioxidant role of haptoglobin Arambašić Jelena & Mihailović Mirjana & Bogojević Desanka & Ivanović-Matić Svetlana & Uskoković Aleksandra & Poznanović Goran & Grigorov Ilijana
Received: 23 January 2012 / Accepted: 5 June 2012 / Published online: 19 June 2012 # University of Navarra 2012
Abstract Haptoglobin is a hemoglobin-binding acutephase protein which possesses anti-inflammatory and antioxidative properties. In this study, we investigated changes in protein expression of rat haptoglobin under diabetes-related inflammatory and oxidative stress conditions induced by an i.p. injection of streptozotocin. The progress of diabetes during an 8-week follow-up period was associated with the increased presence of haptoglobin in the serum and in the liver. This increase was most prominent during the first 2 weeks after which it started to decline. Temporary changes in haptoglobin expression strongly correlated with the serum levels of TNF-α and IL-6. Lower haptoglobin expression at the fourth week and thereafter correlated with a decrease in TNF-α concentration and changes in the TNF-α/IL-6 ratio. Based on the decrease of GSH/GSSG ratio and antioxidant enzyme activities in the liver until the end of fourth week, it was concluded that the liver was exposed to oxidative stress and injury which in the presence of the abovementioned inflammatory mediators lead to different haptoglobin expression profiles at different stages of diabetes. An inverse correlation was observed between the haptoglobin and free iron serum levels in A. Jelena : M. Mirjana : B. Desanka : I.-M. Svetlana : U. Aleksandra : P. Goran : G. Ilijana (*) Department of Molecular Biology, Institute for Biological Research “Siniša Stanković”, University of Belgrade, Bulevar Despota Stefana 142, 11060 Belgrade, Serbia e-mail: [email protected]
diabetic rats. The higher levels of haptoglobin during the first 2 weeks were accompanied by a lower level of free iron. In view of the established function of haptoglobin, we discuss its possible role in decreasing oxidative stress during the early stage of diabetes. Keywords Diabetes . TNF-α . IL-6 . Oxidative stress . Haptoglobin expression
Introduction Haptoglobin is a hemoglobin scavenger protein that is constitutively present in the serum. It belongs to the functionally heterogenous group of proteins that are referred to as positive acute-phase (AP) proteins whose synthesis and secretion by hepatocytes and subsequent serum concentrations undergo to an increase in the course of the AP response [12]. The AP response represents a major pathophysiological reaction in which the physiological, homeostatic mechanisms are modified to different set-points. This response is a major contributor to an organism’s defensive and adaptive capabilities against infection, inflammation, and oxidative stress. Haptoglobin possesses anti-inflammatory and immunomodulatory properties and functions as an antioxidant as a direct result of
Data Loading...
