Protective Effects Of Curcumin On Lung Injury Induced By Intestinal Ischemia Reperfusion In Rats And The Involvement Of NFκB In IIR

Intestine ischemia reperfusion (IIR) is a pathophysiologic process frequently during the therapy of many diseases such as serious trauma and shock and may result in many serious complications. The enterogenic infection is the effect induced by the impaired intestinal mucosal barrier, and it is the key cause that leads to systemic inflammatory response syndrome and multiple organ dysfunction syndrome. Intestine ischemia reperfusion not only hurts the intestines but also causes the remote organs such as lung failure. The transcription factor nuclear factor kappaB (NFκB) can regulate transcription and expression of many inflammatory mediators. The research has proved that the lung damage caused by IIR is related with NFκB, and the activation of NFκB plays an important role in the IIR. Curcumin, a member of the curcuminoid family of compounds, is a yellow colored phenolic pigment obtained from powdered rhizome. Present research discovered that curcumin has powerful anti-inflammatory and antibacterial effects. As an inhibitor of NFκB, it has many effective effects.Objective: To investigate the protection of curcumin on lung during intestinal ischemia reperfusion injury (IIR) and to examine the possible mechanism of this process.Method: Rats were randomly divided into 4 groups: control group, IIR group, the 1 mg/kg curcumin treated (low dosage group) and the 5 mg/kg curcumin treated (high dosage group) (n=6). The IIR model was established by clamping superior mesenteric artery (SMA) for 1 hour and reperfusion for 2 hours. The 2 treated groups were administrated with femoral vein injection of 1 mg/kg and 5 mg/kg curcumin 10 min before reperfusion. Lung histology and bronchia alveolus lung fluid (BALF) protein were assayed. Serum IL-6 and TNF-α, lung superoxide dismutase (SOD) and myeloper- oxidase (MPO) as well as the expression level of NFκB and ICAM-1 were measured.Result: Lung injury induced by intestinal IIR, was characterized by edema, hemorrhage and neutrophil infiltration as well as the significant rising of BALF protein. In model groups, compared with control group, the levels of serum IL-6, TNF-α, lung MPO increased (P<0.01, P<0.01, P<0.01) and lung SOD decreased (P<0.01) in I/R group. Strong positive expression of NFκB P65 and ICAM-1 was observed. After the administration of low and high dosage curcumin, the level of BALF protein, serum IL-6, TNF-α, decreased significantly (P<0.01, P<0.01, P<0.01) and lung SOD increased obviously (P<0.05) while lung MPO decreased (P<0.01) only in the low dosage group, the expression of NFκB P65 and ICAM-1 decreased when compared to IIR group.Conclusion: (1) This study demonstrated that intestinal IIR may result in severe lung damage; (2) The mechanism of lung injury induced by IIR is complicated, which has relation with the activation of NFκB; (3) Curcumin can protect lung against IIR injury which may be related with inhibiting the activation of NFκB.