Differential Regulation of Cytokines and Transcription Factors in Liver by Curcumin Following Hemorrhage/Resuscitation


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Abstract

Inflammatory cytokines interleukin 1 (IL-1), IL-2, IL-6, and tumor necrosis factor-α (TNF-α) have been recognized as important mediators of pathophysiological and immunological events associated with shock. These inflammatory events after hemorrhage and resuscitation are characterized by the activation of transcription regulators such as nuclear factor-κB (NF-κB) and activator protein-1 (AP-1). Curcumin, an anti-inflammatory remedy used in Indian medicine, is known to suppress NF-κB and AP-1 activation and also to reduce ischemia-reperfusion injuries in animal models. Therefore, the aim of this study was to determine whether administration of curcumin before hemorrhagic shock has any salutary effects on cytokines and the redox-sensitive transcription factors NF-κB and AP-1. mRNA levels of IL-1α, IL-1β, IL-2, IL-6, IL-10, and TNF-α were determined by reverse transcriptase-polymerase chain reaction in rat livers collected at 2 and 24 h after hemorrhage/resuscitation. The effect of curcumin on the activation of NF-κB and AP-1 was determined by electrophoretic mobility shift assays. Significant increases in the levels of liver cytokines IL-1α, IL-1β, IL-2, IL-6, and IL-10 were observed in the 2-h posthemorrhage/resuscitation group compared with sham animals. In contrast, oral administration of curcumin for 7 days followed by hemorrhage/resuscitation regimen resulted in significant restoration of these cytokines to depleted levels, and, in fact, IL-1β levels were lower than sham levels. Also, the 24-h postresuscitation group showed similar patterns with some exceptions. NF-κB and AP-1 were differentially activated at 2 and 24 h posthemorrhage and were inhibited by curcumin pretreatment. Serum aspartate transaminase estimates indicate decreased liver injury in curcumin-pretreated hemorrhage animals. These results suggest that protection against hemorrhage/resuscitation injury by curcumin pretreatment may result from the inactivation of transcription factors involved and regulation of cytokines to beneficial levels.

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