IL-10 supplementation increases animal survival. Obese (Ob) or lean (wild type, WT) mice were subjected to 15 min, warm I/R or sham surgery and monitored for 24 hrs. Some Ob mice were given 1 μg IL-10 (Ob IL-10) 30 min prior to I/R. IL-10 pretreatment restored survival in ob/ob mice (p<0.05, log rank). Data are expressed as mean ± SEM; n = 3-6/group.
IL-10 decreases hepatic injury following I/R. Mice subjected to I/R as described in Figure 1 were evaluated for ALT, an indicator of liver damage, at six and 24 hrs post-reperfusion. Hepatic injury was significantly reduced in IL-10-supplemented ob/ob (Ob IL-10) mice compared to ob/ob controls (Ob) at 24 hrs (*p<0.05). Data are expressed as mean ± SEM; n = 3-6/group.
IL-10 pretreatment modulates post-I/R cytokine expression. Mice were evaluated for hepatic cytokines IL-1β, TNF-α, and IL-10 mRNA at six hrs post-reperfusion by qRT-PCR. IL-1β mRNA levels were significantly upregulated in the livers of ob/ob (Ob) animals as compared to lean control (Wt) and IL-10-pretreated ob/ob (Ob IL-10) animals. No significant changes in TNF-α expression were noted. Elevation of IL-10 transcripts in livers of Ob animals after I/R was significantly less than that seen in Wt and Ob IL-10 mice. Fold-change is a comparison to mice not subjected to I/R. Means with different lettered subscripts within each group are significantly different from each other (a is significantly different from b), p<0.05. Data are expressed as mean ± SD; n = 3-6.
LC-treated ob/ob animals have increased injury. Obese (Ob) or lean (wild type, WT) mice were subjected to 15 min, warm, I/R or sham surgery and monitored for 24 hrs. Some Ob mice were given LC (Ob LC), 48 hrs prior to I/R to depleted KC. Hepatic injury was significantly increased in OB LC mice at six hrs when assessed by measuring circulating levels of ALT (*p<0.05). Data are expressed as mean ± SEM; n = 3-6.
LC-treated ob/ob animals do not show upregulated hepatic IL-10 mRNA expression in response to I/R. Mice from figure 4 were evaluated for hepatic IL-10 mRNA levels six hrs post-reperfusion as assessed by qRT-PCR. Both ob/ob (Ob) and LC-treated ob/ob (Ob LC) mice expressed fewer hepatic IL-10 mRNA transcripts compared to lean (Wt) counterparts. Fold-change is a comparison to mice not subjected to I/R. Means with different lettered subscripts within each group are significantly different from each other (a is significantly different from b), p<0.05. Data are expressed as mean ± SD; n = 3-6.
3 Department of Drug Discovery and Biomedical Sciences,Medical University Of South Carolina, Charleston, SC, USA, and
4 R.H. Johnson Veterans Administration Medical Center, Charleston, SC, USA
* Correspondence: Kenneth D Chavin, MD, Ph.D. Division of Transplant, Department of Surgery Medical University of South Carolina. 96 Jonathan Lucas Street, 409 CSB. PO Box 250611. Charleston, SC 29425-0611
Steatotic livers are more sensitive to ischemia/reperfusion (I/R) and are thus routinely rejected for transplantation because of their increased rate of primary nonfunction (PNF). Lean livers have less I/R-induced damage and inflammation due to Kupffer cells (KC), which are protective after total, warm, hepatic I/R with associated bowel congestion. This protection has been linked to KC-dependent expression of the potent anti-inflammatory cytokine interleukin-10 (IL-10). We hypothesized that pretreatment with exogenous IL-10 would protect the steatotic livers of genetically obese (ob/ob) mice from inflammation and injury induced by I/R. Lean and ob/ob mice were pretreated with either IL-10 or liposomally-encapsulated bisphosphonate clodronate (shown to deplete KC) prior to total, warm, hepatic I/R. IL-10 pretreatment increased survival of ob/ob animals at 24 hrs post-I/R from 30% to 100%, and significantly decreased serum ALT levels. At six hrs post-I/R, IL-10 pretreatment increased IL-10 mRNA expression, but suppressed up-regulation of the pro-inflammatory cytokine IL-1β mRNA. However, ALT levels were elevated at six hrs post-I/R in KC-depleted animals. These data reveal that pretreatment with IL-10 protects steatotic livers undergoing I/R, and that phagocytically active KC retain a hepatoprotective role in the steatotic environment.