The Role Of Rho Kinase In Lung Injury Induced By Intestinal Ischemia Reperfusion In Rats And The Protective Effects Of Hydrochloride Fasudil

Background: The obstacle of intestinal ischemia-reperfusion (IIR), in practical surgery, is one of the most serious injuries, not only occurs in acute abdomen such as intestinal obstruction, mesentery arterial embolism but also in shock after serious hurt and burn. IIR cause the death of intestine mucous cell, and the barricade of intestine mucous is destroyed. When the permeability of blood vessel increases, endotoxin is absorbed in blood and bacteriums transform into systemic circulation, then, so many cytokines and inflammatory factor are released, finally distant tissue severe destruction, even the systemic inflammatory response syndrome (SIRS), and multiple organ dysfunction syndrome (MDOS), but ARDS caused by lung injury with a high case fatality ratio plays a key role in IIR. Rho kinase is downstream target molecule of small GTP-binding proteins, and it participates in many physiological functions such as smooth muscle contraction and cell migration. Meanwhile, Rho kinase plays a part in inflammation .There have been no studies on the relation of Rho-kinase in lung injury induced by IIR till now.Hydrochloride Fasudil (HF), a protease inhibitor, which has potent capacity of modulating cell metabolization and gene expression and which probably has protective effects on lung injury induced by intestine ischemia reperfusion.Objective: This article is designed to examine the role of Rho kinase in the mechanism of lung injury induced by intestinal ischemia reperfusion in rats and to investigate the preconditioning protective effects of Hydro- chloride Fasudil, in order to provide preclinical pharmacological basis for its new clinical uses.Method: Rats were randomly divided into 4 groups: sham group, IR group, HF (15mg/kg) preconditioning group, and HF (7.5mg/kg) pre- conditioning group The IIR model was established by clamping superior mesenteric artery (SMA) for 1 hour and reperfusing for 2 hours. The HF pretreatment groups were administrated intraperitoneally with two different doses of fasudil 1 hour before operation, while the control group and the IR group were given the equivalent 0.9% NS instead. In the sham group, SMA was only isolated without clamping. Blood sample, intestine and lung tissue samples were collected after reperfusion 2 hours. Lung and intestine histo- logy were observed. The changes of superoxide dismutase (SOD) and myeloperoxidase (MPO) in the tissue of lung and intestine at the end of reperfusion were determined. The serum levels of creatine kinase-B (CK-B), tumor necrosis factor-α(TNF-α) and interleukin-6 (IL-6) were measured. The expressions of eNOS and p-Moesin were performed by Western- Blotting analysis.Result: Compared with sham group, in IR group, intestine and lung were destroyed obviously on pathology. The levels of serum TNF-α, IL-6 and CK-B, increased (P<0.01, P<0.01, P<0.01), the activity of MPO raised significantly in lung and intestine tissues, but the activity of SOD was weakened (P<0.01, P<0.01). At the same time, strong positive expressions of tissue p-Moesin and eNOS were detected. Administration of fasudil remarkably ameliorated tissue injury demonstrated as the decreasing level of serum CK-B and protein content of BALF (P<0.01, P<0.01). Compared with IR group, the level of TNF-α, IL-6 in serum and MPO activity in the tissues decreased significantly (P<0.01, P<0.01), meanwhile, SOD activity increased obviously (P<0.01). The expressions of p-Moesin and eNOS markedly ameliorated respectively.Conclusion: 1) This study demonstrated that intestinal II/R may result in sincerely lung damage, the mechanism may be involved of oxidation injury, activated neutrophilic granulocyte accumulation and cytokines mediators. 2) The mechanism of lung injury induced by IIR is complicated which has relation on the activation of Rho-kinase. 3) HF can protect lung against IIR injury, which may be associated with ameliorating oxidation injury, increasing the production of eNOS, decreasing the aggregation and activation of neutrophilic granulocyte and the release of cytokines media- tors, which may be related with inhibiting the activation of Rho kinase.