Downregulation of hepatic cytochrome p-450 isoforms and PPAR-gamma: Their role in hepatic injury and proinflammatory responses in a double-hit model of hemorrhage and sepsis

作者：Higuchi Shinya; Wu Rongqian; Zhou Mian; Ravikumar Thanjavur S; Wang Ping^*

来源：Journal of Surgical Research, 2007, 137(1): 46-52.

DOI：10.1016/j.jss.2006.04.019

• cytochrome P-450
• PPAR-gamma
• double-hit model
• hemorrhage
• sepsis
• liver

Background. The "double-hit" model of hemorrhage and sepsis mimics the critically M patient admitted to the surgical intensive care unit. Although the protein expression of a cytochrome (CYP) P-450 isoform CYP1A2 is reduced in the late stage of sepsis, the effect of hemorrhage on CYP isoforms and the anti-inflammatory nuclear receptor peroxisome proliferator-activated receptor-gamma (PPAR-gamma) has not been investigated. We hypothesized that hemorrhage down-regulates CYP isoforms and PPAR-gamma in the liver, which plays an important role in producing tissue injury and proinflammatory responses after the subsequent sepsis (i.e., double-hit).
Materials and methods. Male Sprague Dawley rats were divided into four groups. Animals in the double-hit group underwent hemorrhage (40 +/- 2 mm Hg for 90 min) followed by fluid resuscitation. Polymicrobial sepsis was induced by cecal ligation and puncture (CLP) 20 h after hemorrhage, and the animals were sacrificed 4 h after CLP. Rats in the hemorrhage-alone group were sacrificed 20 h after the insult. Rats in the CLP-alone group were sacrificed 4 h after the onset of sepsis. Animals in the sham-operated group underwent neither hemorrhage nor CLP. The gene expression of P-450 isoforms (i.e., CYP1A2 and 2C11) and PPAR-gamma in the liver was determined using RT-PCR. Serum concentrations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate, and proinflammatory cytokines (i.e., IL-6, TNF-alpha) were also assessed.
Results. In the hemorrhage-alone group, hepatic mRNA expression of CYP1A2, CYP2C11, and PPAR-gamma was significantly down-regulated 20 h after the initial stress compared with sham-operated rats. Double-hit did not appear to further decrease CYP and PPAR-gamma gene expression. In contrast, serum levels of AST, ALT, lactate, IL-6, and TNF-a did not change significantly in either hemorrhaged or septic animals. Those organ injury indicators and cytokines, however, were significantly elevated after the double-hit of hemorrhage and sepsis.
Conclusions. Hepatic CYP1A2, CYP2C11, and PPAR-gamma were down-regulated after the initial stress (hemorrhage). These down-regulated CYPs and PPAR-gamma seem to work as important factors contributing to the progression of organ injury and proinflammatory responses after the second stress (CLP).

• 出版日期2007-1
• 单位河北医科大学