Role Of Resveratrol On The Hemorheology In Rats Following Lipopolysaccharide Challenge Through Intraperitoneal Injection

Acute peritonitis induced-sepsis is a common critical pathological process. During sepsis, refractory hypotension, extensive microthrombus,abnormal hemodynamics and microcirculatory disturbance lead to organ dysfunction and damage, and/or death. Numerous studies showed that resveratrol(Res) pre-treatment or post-administration could alleviate the organ injury in animal models of endotoxic shock or sepsis induced by cecal ligation and puncture, lipopolysaccharide(LPS) intravenous injection, LPS intraperitoneal injection, and airway instilment of LPS. Its mechanism is related to anti-inflammatory response and relieving oxidative stress. However, the detailed mechanism needs further investigation. Abnormal rheological property play an important promote role during the organ injury induced by endotoxic shock. Whereas,whether Res treatment improving the abnormal rheological property during abdominal bacterial infection induced-sepsis, has not been reported.Therefore, the current study established the model of LPS challenge via intraperitoneal injection, furthermore, observed the role of Res on the rheological property in rats following LPS challenge.Twenty-four healthy male Wistar rats(in clean grade) were randomly divide into four groups, namely, the sham, sham+Res, LPS and LPS+Res,with six rats in each group. The LPS administration and Res treatment were performed under a waking state. Firstly, rats in the LPS and LPS+Res groups, received an intraperitoneal injection of LPS(8 mg/kg).Similarly, rats in the sham and sham+Res groups, received anintraperitoneal injection of normal saline(1.6 ml/kg). Subsequently, after1 h of LPS injection, the treatment with Res(30 mg/kg) was performed through intramuscular injection in the sham+Res and LPS+Res groups. At the same time, the same amount of dimethylsulfoxide(DMSO, 100 μl/kg)instead of Res was given to the sham and LPS group as control.At 4.5 h following Res or DMSO administration, all rats were drugged with pentobarbital sodium(1%, 50 mg/kg). Then, the right femoral operation was performed, and the femoral artery was separated and cannulated for continuously monitoring the animals’ mean artery pressure(MAP) for 10 min using the Powerlab biological signal collecting and processing system. Subsequently, the abdominal was performed for the observation of regional blood flow of liver, stomach, spleen, intestine,and kidney with the laser speckle flow monitoring system. After the observation of regional blood flow, the neck surgery was performed, and the common carotid artery was separated and cannulated for harvesting the whole blood sample. Part of blood sample about 0.1 ml was fixed in EP tube containing EDTA·K2 for the examinations of erythrocyte parameters including red blood cell content(RBC), hemoglobin(Hb), hematocrit(Hct), mean corpuscular volume(MCV), mean corpuscular hemoglobin(MCH), mean corpuscular-hemoglobin concentration(MCHC), and red blood cell distribution width(RDW), leukocyte parameters including white blood cell counts(WBC), percentage of neutrophil, percentage of lymphocyte, absolute counts of neutrophil or lymphocyte, platelet parameters including platelet counts(Plt), plateletocrit(PCT), mean platelet volume(MPV), platelet distribution width(PDW) platelet-large cell ratio(P-LCR). The 3.0 ml of the heparinized arterial whole blood samples were loaded to sensing slot via straw under negative pressure conditions, and the blood viscosity was analyzed with a hemorrheology analyzer. After blood sample preparation, the myocardium, kidney, lung were harvested from a fixed location rapidly. Parts of these tissues werehomogenized to prepare homogenate for the measurement of myeloperoxidase(MPO) using the method of H2O2, L-selectin, P-selectin,intercelluar cell adhesion molecule 1(ICAM-1), soluble platelet-endothelial cell adhesion molecule 1(sPECAM-1) with the method of ELISA.Results in the present study showed that the MAP, whole blood viscosity at low and medium shear rates, blood flow in spleen and kidney in rats at 6 h of LPS administration were observably decreased than the sham and sham+Res groups, but there were no obviously roles of LPS administration on the erythrocyte parameters and whole blood relative viscosity at low and medium shear rates. Meanwhile, Res treatment induced decreases in the RDW-CV, the whole blood viscosity at high,medium and low shear rates, the whole blood relative viscosity at high shear rate, the blood flow in stomach, and an increase in MCH, but no significant role on MAP. In addition, there were no obviously changes in plasma viscosity, blood flow in the liver, spleen and intestine among the four groups.At the same time, results showed that LPS administration induced decreases in the Plt, PCT, WBC, absolute counts of neutrophil or lymphocyte, simultaneously, Res treatment obviously increased the WBC and absolute counts of lymphocyte, decreased the percentage of lymphocyte. Fourthermore, LPS intraperitoneal injection decreased the ICAM-1 level in pulmonary tissue and increased the ICAM-1 level in renal tissue, Res treatment obviously increased the L-selectin and ICAM-1levels in pulmonary tissue. Moreover, there were no obviously changes in the P-selectin and sPECAM-1 levels in lung, kidney and myocardium,L-selectin levels in kidney and myocardium, ICAM-1 level in myocardium among the four groups. Meanwhile, LPS intraperitoneal injection increased the MPO activity in lung, which was abolished by Res treatment.In summary, these current results in this study indicated that LPS administration-induced abnormal rheology properties, including decreased whole blood viscosity at low and medium shear rates, blood flow in spleen and kidney, Res treatment fouther expanded the quasi sympathetic effects of LPS at early stage, along with reducing the whole blood viscosity and regional blood flow following LPS challenge. Meanwhile, LPS intraperitoneal injection induced a decrease in WBC, it is related to the adhesion and infiltration of WBC to pulmonary tissue, which is an important factor of inflammatory response in pulmonary tissue induced by LPS administration. Res treatment inhibited the role of adhesion and infiltration of WBC, which is a mechanism of Res reducing the inflammatory response induced by LPS administration. Moreover, the role and mechanism of Res alleviating the adverse effects of LPS administration need further investigation.