AIM: To investigate the effects of electrical stimulation of vagus nerve on gut injury following intestinal ischemia-reperfusion in rats. METHODS: 30 adult male Wistar rats subjected to bilateral cervical vagotomy were randomly divided into three groups (n=10 per group): (1) Intestinal ischemia-reperfusion group (group I/R): laparotomy and I/R induced by clamping arteria mesenterica superior for 1 h followed by reperfusion for 2 h. (2) Vagus nerve stimulation group (group VNS): laparotomy, I/R and electric stimulation with pulse train of constant amplitude 5V, pulse width 2 ms and frequency 1 Hz at the left caudal vagus ends for 20 minutes before and after occlusion. (3) Sham control group (group SC): sham operation and sham stimulation. Carotid artery was cannulated for mean arterial pressure (MAP) monitoring. A strip of small intestine was taken from distal end of ileum for light microscopic (LM) and transient electron microscopic (TEM) examination at the time of 2 h after reperfusion. Improved Chiu’s scale was used to quantitatively assay the damage degree. The levels of malondialdehyde (MDA) and TNF-? in plasma were detected. RESULTS: MAP in every group kept steady during ischemia, but decreased gradually with the prolongation in the time of reperfusion. MAP decreased more dramaticly in group I/R than that in group VNS (P

Aim To investigate the the protective effects of a novel recombinant Trichinella spiralis 38 ku protein ( rTsP38 ) on intestinal I/R injury and the po-tential mechanisms. Methods Male BALB/c mice were randomly divided into sham group ( group S) , in-jury group ( group I) , rTsP38 vaccinated group ( group T) and adjuvants vaccinated group ( group A ) , and received subcutaneously phosphate buffer solution (PBS), PBS, rTsP38, or adjuvants, respectively, at 2-week intervals 6 weeks before the surgical proce-dure. Results Intestinal I/R caused severe intestinal injury evidenced by significant increases in modified Chiu 's score and neutrophils infiltration, accompanied by decreases in daily food intake and body weight. The mRNA level of arginase-1 ( Arg-1 ) was decreased and the mRNA level of inducible nitric oxide synthase 2 ( NOS2) was increased in group I. RTsP38 significant-ly ameliorated intestinal injury and improved intestinal function following intestinal I/R accompanied by de-crease in neutrophils infiltration and increase in cell proliferation in the intestine, compared to mice without rTsP38 pretreatment. Fold changes of Arg-1 mRNA level were significantly increased in group T. Conclu-sions These findings indicate that rTsP38 exerts pro-tection on intestinal I/R injury in mice via promoting M2 macrophages polarization.

[Objective] To explore whether necroptosis is involved in the mechanism of lung injury induced by intestinal ischemia-reperfusion.[Method] Thirty-two healthy male Sprague-Dawley rats were randomly assigned into 4 groups (n--8):sham operation group (sham group),isehemia/ reperfusion group (I/R group),necroptosis inhibitor necrostatin-1 group (Nec-1 group) and solvent dimethyl sulfoxide (DMSO) group (DMSO group).Model of intestinal I/R injury was produced by clamping the superior mesenteric artery for 1.5 h followed by 6 h reperfusion in rats.Necrostatin-1 1.0 mg/kg was administered 30 min before occlusion in Nec1 group,while the equal volume of DMSO was given instead in DMSO group.The rats were sacrificed at 6 h of reperfusion and the lung tissues were removed for measurement of wet-dry ratio and microscopic examination and scored.The expression of receptor-interacting protein 1 (RIP1) and receptor-interacting protein 3 (RIP3) in lung tissues was detected using Western-blot and immunohistochemistry.[Result] Compared with sham group,lung morphology score and wet/dry ratio in I/R,DMSO group raised (P ＜ 0.05).Lung morphology score and wet/dry ratio statistically declined in Nec-1 group compared with I/R and DMSO group (P ＜ 0.05),while there was no statistical difference of wet/dry ratio between sham group and Nec-1 group (P ＞ 0.05).As the result of westernblot and immunohistochemistry showed,the expression of RIP1 and RIP3 was up-regulated in I/R group and DMSO group (P ＜0.05),which was inhibited by Nec-1 in Nec-1 group (P ＜ 0.05).[Conclusion] Necroptosis is involved in the mechanism of lung injury induced by intestinal ischemia-reperfusion,and Nec-1,the special inhibitor of RIP1,can reduce the injury.

Objective To investigate the changes of proteins expressions in intestinal mucosa of rats after is chemic postconditioning (IPo) against intestinal ischemic/reperfusion (Ⅱ/R) injury of intestine in order to elucidate its potential mechanisms of protective role. Methods Sixteen SD rats were randomly divided into Ⅱ/R group and IPo group ( n = 8). Rats of both groups received an episode of ischemic/reperfusion insult to intstine that was made by occlusion of the superior mesenteric artery (SMA) for 60 minutes. Rats of IPo group underwent three additional episodes of clamping SMA on for 30 seconds and off for 30 seconds successively after prolonged reperfusion/reperfusion of intestine. The intestinal mucosa was taken by scratching immediately after reperfusion in both groups, and total proteins were separated by immobilized pH gradient (IPG) based two-dimensional gel electrophoresis (2-DE). The differentially expressed proteins were analyzed using Image Master 2D Elite 5.0 image analysis software, and the proteins were cut out from the gel and then identified using MALDI-TOF-MS. The biological information of these proteins was looked for in the database of these peptide mass finger-printing (PMF) .Results Ten differentially expressed proteins were found, of which 6 were up-regulated and 4 were down-regulated in IPo group. Nine proteins were identified and characterized by their bioelements including aldose reductase and aldehyde dehydrogenase that were related to anti-oxidative stress and inhibition of cell apoptosis. Conclusions The well-reproducible 2-DE profiles of intestinal mucosa in II/R and IPo groups were established. The potentially protective effects of IPo may be attributed to up-regulating protein expressions of aldose reductase and aldehyde dehydrogenase, and thereby suppressing oxidative stress and cell apoptosis.

ObjectiveTo investigate the role of 15-F2t-isoprostane in intestinal injury induced by intestinal ischemia/reperfusion (I/R) in rats.MethodsThirty-two pathogen free adult male SD rats weighing 230-255 g were randomly divided into 4 groups ( n =8 each):group sham operation (group S) ; group intestinal I/R; group SQ-29548 (TXA2 receptor antagonist) (group SQ) and group DMSO (the solvent).Intestinal I/R was induced by 60 min occlusion of superior mesenteric artery (SMA) followed by 120 main reperfusion in groups I/R,SQ and DMSO SQ-29548 2 μmol/kg and DMSO were injected subcutaneusly at abdominal wall at 30 min before SMS in groups SQ and DMSO respectively.Arterial blood samples were taken at 120 min of reperfusion for determination of serum diamine oxidase (DAO) activity and 15-F2t-isoprostane,endothelin-1 (ET-1) and thromboxane B2 (TXB2) concentrations.Intestinal tissues were removed for microscopic examination and determination of myeloperoxidase (MPO) and SOD activities,MDA and lactate contents.Intestinal damage was assessed and scored according to Chiu (0 =normal,5 =disruption of tunica propria,bleeding and ulceration).ResultsIntestinal I/R significantly increased Chiu's score,MDA and lactate contents and MPO activity and decreased SOD activity in intestine in group I/R as compared with group S.SQ-29548 pretreatment significantly decreased Chiu's score,lactate content and MPO activity in intestine and increased intestinal SOD activity and decreased serum DAO activity and ET-1 concentration in group SQ as compared with group I/R.Conclusion15-F2t-isoprostane is involved in the development of intestinal injury induced by intestinal I/R by activating TXA2 receptor,increasing ET-1 production and promoting neutrophil infiltration.

Objective To investigate the effects of intestinal ischemia-reperfusion (I/R) on the brain in rats. Methods Sixty-four healthy male SD rats weighing 250-300 g were randomly allocated to one of 2 groups (n = 32 each): sham operation group (S) and intestinal I/R group (I/R). Intestinal I/R was produced by occlusion of superior mesenteric artery (SMA) for 90 min followed by reperfusion. Eight animals were sacrificed at each of the following time points: 2, 6, 12 and 24 h of reperfusion (T1-4) in each group. After a median sternotomyblood samples were taken from left ventricle for measurement of plasma TNF-α and IL-6 (by ELISA). Intestine and brain tissue was harvested for microscopic examination and detection of apoptosis ( by TUNEL). The cognitive function was tested using Morris water maze at 24 h. Results No abnormality was found in intestine and brain tissue in group S. Intestinal damage and neurodegeneration were detected in group I/R. Intestinal I/R significantly increased cerebral apoptosis in group I/R compared with group S. Plasma TNF-a and IL-6 concentrations were significantly higher at T1-4 in group I/R than in group S. The escape latency and swimming distance were significantly increased, while the number of crossing the platform was decreased in group I/R compared with group S. There was no significant difference in the swimming speed between the 2 groups. Conclusion Intestinal I/R can induce brain injury and lead to cognitive dysfunction. I/R-induced release of inflammatory mediators and neuronal apoptosis are involved in the underlying mechanism.

Objective To investigate the effects of remote limb ischemic preconditioning (RLIP) on the lung injury in patients undergoing abdominal aortic aneurysm repair.Methods Sixty-two ASA Ⅱ or Ⅲ patients of both sexes,aged 54-72 yr,with body mass index 21-36 kg/m2,undergoing elective abdominal aortic aneurysm repair,were randomly divided to 2 groups ( n =31 each):control group (group C) and RLIP group.RLIP consisted of two 5-min cycles of left upper limb ischemia induced by a blood pressure cuff placed on the left upper arm and inflated to 200 mm Hg,with an intervening 5 min of reperfusion,during which time the cuff was deflated.RLIP was performed after anesthesia induction and before the start of surgery.Arterial and venous blood samples were taken at 10 min after intubation (T0),and 30 min and 4,8,12 and 24 h after aortic unclamping (T1-5) for blood gas analysis and determination of the concentrations of serum interleukin (IL)-6,tumor necrosis factor (TNF)-α,and plasma malondialdehyde (MDA) and superoxide dismutase (SOD) activity.The alveolar-arterial oxygen pressure difference (PA-aO2 ) and respiratory index (RI) were calculated.The peak airway pressure (Ppeak),plat airway pressure (Pplat) and positive end expiratory pressure (PEEP) were recorded at the same time points mentioned above to calculate dynamic lung compliance (Cd) and static lung compliance (Cs).The incidence of hypoxemia,extubation time and duration of stay in intensive care unit (IGU) were also recorded.Results Compared with group C,PA-aO2,RI and the concentration of IL-6 were significantly decreased at T3-5,Cs,Cd and SOD activity were significantly increased at T2-5,and the concentrations of TNF-α and MDA were significantly decreased at T2-5 in group RLIP ( P ＜ 0.05).Compared with group C,the incidence of hypoxemia was significantly decreased,and extubation time and duration of stay in ICU were significantly shortened in group RLIP ( P ＜ 0.05).Conclusion RLIP can reduce the lung injury through inhibition of the inflammatory response and lipid peroxidation in patients undergoing abdominal aortic aneurysm repair.

Objective To investigate the optimum dose of dexmedetomidine when combined with propofol for induction of anesthesia.Methods One hundred and twenty ASA physical status Ⅰ or 1Ⅱ patients of beth sexes,aged 18-60 yr,with body mass index of 18.5-30.0 kg/m2,scheduled for elective ophthalmologic operation under general anesthesia,were randomly divided into 6 groups (n =20 each) using a random number table:normal saline group (NS group) and different doses of dexmedetomidine groups (D1-D5 groups).Different loading doses of dexmedetomidine 0.2,0.4,0.6,0.8 and 1.0 μg/kg (in normal saline 50 ml) were infused intravenously in D1-D5 groups,respectively.The equal volume of normal saline was infused over 15 min in group NS.After 10 min observation,target-controlled infusion (TCI) of propofol was started.The initial target plasma concentration was set at 3.2 μg/ml.Loss of consciousness was considered to be positive response.The median effective concentration (EC50) and 95％ confidence interval of propofol TCI required for loss of consciousness were calculated.After administration of dexmedetomidine,the development of adverse effects was recorded before propofol TCI.Results Compared with NS group,the EC50 of propofol TCI required for loss of consciousness was significantly decreased in D2-D5 groups,and no significant change was found in the EC50 of propofol TCI required for loss of consciousness in D1 group.The EC50 of propofol TCI was decreased gradually with the increasing doses of dexmedetomidine between D1 and D2 groups,between D2 and D3 groups,and between D4 and D5 groups,while there was no significant difference in the EC50 of propofol TCI required for loss of consciousness between D3 and D4 groups.The incidence of hypotension was 5％ (D3 group),11％ (D4 group) and 31％ (D5 group),and the incidence of bradycardia was 0 (D3 group),11％ (D4 group),and 19 ％ (D5 group).No hypotension and bradycardia developed in D1 and D2 groups.The incidence of hypotension and bradycardia was significant increased in D4 and D5 groups as compared with NS,D1,D2 and D3 groups.Conclusion The optimum dose of dexmedetomidine is 0.4μg/kg when combined with propofol for induction of anesthesia.

Objective To evaluate the role of necroptosis in intestinal ischemia-reperfusion (I/R) injury in rats.Methods Thirty-two healthy male Sprague-Dawley rats,weighing 200-220 g,were randomly assigned into 4 groups (n =.8 each) using a random number table:sham operation group (Sham group),I/R group,necroptosis inhibitor necrostatin-1 group (Nec-1 group) and solvent dimethyl sulfoxide (DMSO) group (group DMSO).Intestinal I/R injury was produced by clamping the superior mesenteric artery for 1 h followed by 24 h reperfusion in rats anesthetized with chloral hydrate.Necrostatin-1 1.0 mg/kg was administered intraperitoneally at 30 min before occlusion in Nec-1 group,while the equal volume of DMSO was given instead in group DMSO.The rats were sacrificed at 24 h of reperfusion and the intestinal tissues were removed for microscopic examination.Intestinal damage was assessed and scored according to Chiu.Blood samples were taken for determination of serum diamine oxidase (DAO) activity.The expression of activitied caspase-3 and receptor-interacting protein 1 (RIP1) in intestinal tissues was detected using Western blot.Results Compared with Sham group,Chiu's score,serum DAO activity,and the expression of activitied caspase-3 and RIP1 was up-regulated in I/R,DMSO and Nec-1 groups.Compared with I/R and DMSO groups,Chiu's score and DAO activity were significantly decreased,the expression of RIP1 was down-regulated,and no significant change was found in the expression of activitied caspase3 in group Nec-1.Conclusion Necroptosis is involved in intestinal I/R injury in rats.

Objective To evaluate the role of necroptosis in liver injury induced by intestinal ischemia-reperfusion (I/R) in rats.Methods Thirty-two healthy adult male Sprague-Dawley rats,weighing 250-300 g,were divided into 4 groups (n=8 each) using a random number table:sham operation group (S group),I/R group,specific necroptosis inhibitor necrostatin-1 group (N group) and dimethyl sulfoxide (DMSO) group (D group).Intestinal I/R was produced by occlusion of the superior mesenteric artery for 1.5 h followed by 6 h of reperfusion.The superior mesenteric artery was only isolated but not ligated in group S.At 30 min before ischemia,necrostatin-1 1 mg/kg (diluted to 200 μl in DMSO) was intraperitoneally injected in group N,while the equal volume of DMSO was given instead in group D.The animals were sacrificed at the end of reperfusion,livers were removed for examination of the pathological changes with a light microscope,and the severity of liver injury was evaluated using the Eckhoff's scale score.Blood samples were collected from the cardiac apex for determination of serum alanine transaminase (ALT) concentrations by enzyme-linked immunosorbent assay.The expression of receptor-interacting protein kinase 1 (RIP1),RIP3 and high-mobility group box 1 protein (HMGB1) in cytoplasm of hepatocytes was detected by Western blot.The location of RIP1 and RIP3 in liver tissues was determined by immunohistochemistry,and the translocation of HMGB1 from nucleus to cytoplasm was tested by immunofluorescence.Results Compared with group S,the Eckhoff's scale score of liver tissues and serum ALT concentration were significantly increased,the expression of RIP1,RIP3 and HMGB1 in liver tissues was up-regulated (P＜0.05),and the hepatocytes in which RIP1 and RIP3 were highly expressed in the portal area were increased in group I/R.Compared with group I/R,the Eckhoff's scale score of liver tissues and serum ALT concentration were significantly decreased,the expression of RIP1,RIP3 and HMGB1 in liver tissues was down-regulated (P＜0.05),and the hepatocytes in which RIP1 and RIP3 were highly expressed in the portal area were decreased in group N,and no significant changes were found in the variables mentioned above in group D (P＞0.05).HMGB1 was expressed in the nucleus of hepatocytes in the portal area in group S;a large number of HMGB1 in hepatocytes in the portal area was translocated to cytoplasm in I/R and D groups;a small number of HMGB1 in hepatocytes in the portal area was translocated to cytoplasm in group N.Conclusion Necroptosis is involved in intestinal I/R-induced liver injury in rats.