Objective To investigate the effects of ketamine on the renal ischemia-reperfusion (IR) injury in rats and the underlying mechanism. Methods Twenty-four male Wistur rats weighing 220-250 g were randomly divided into 4 groups (n=6 each): sham operation group (group S), IR group, ketumine 2 mg/kg group (group K_1), ketamine 10 mg/kg group (group K_2). The rats were anesthetized with intraperitoneal chloral hydrate 300 mg/kg. Renal ischemia was induced by clamping the left renal artery for 45 min followed by 6 h of repednsion using an atraumatic clamp. In group K_1 and K_2, ketaminc 2 and 10 mg/kg were injected via the caudal vein 5 min before the repedusion respectively. The rats were killed at 6 h of reperfusion, and blood samples were collected from the right auricle for measurement of serum creatiniue (Cr) and blood urea nitrogen (BUN) concentrations. Pathological changes in renal tissues were observed with light and electron microscopes. The expression of Fas and Caspsse-3 in the renal tubular epithelial cell was determined by immuno-histochemistry. The apeptosis in the renal tubular epithelial cell was detected by TUNEL assay. Apeptotic index (AI) was calculated. Results Compared with group S, the levels of serum Cr and BUN, expression of Fas and Caspase-3 and AI were significantly increased in group IR, K_1 and K_2 (P < 0.01). The levels of serum Cr and BUN, expression of Fas and Caspase-3 and AI were significantly lower in group K_(1,2) than in group IR and in group K2 than in group K_1 (P<0.01). The microscopic examination showed that the renal IR injury was obviously attenuated in group K_2 compared with group K_1. Conclusion Ketamine can attenuate the renal injury induced by IR in a dose-dependent manner in rats. The underlying mechanism may be related to the inhibition of apoptosis in the renal tubular epithelial cell.

Objective To evaluate the effect of ketamine and elonidine on P2X4R mRNA expression in the spinal cord in a rat model of neuropathic pain.Methods Eighty male SD rats weighing 180-220 g were randomly divided inte 5 groups (n = 16 each): sham operation group (group S),neuropathic pain group (group NP),ketamine group (group K),clonidine group (group CL) and ketamine + clonidine group (group KC).The animals were anesthetized with intraperitoneal chloral hydrate 400 mg/kg.The right sciatic nerve was exposed and four ligatures were placed on the sciatic nerve at 1 mm interval.In group S,the right sciatic nerve was exposed but not ligated,and in the other groups four ligatures were placed around the right sciatic nerve (chronic constrictive injury,CCI) as described by Bennett.The animals were injected intraperitoneally with ketamine 10 mg/kg,clonidine 1 mg/kg,and ketamine 5 mg/kg + clonidine 0.5 mg/kg in normal saline 2 ml in group K,CL and KC respectively,while normal saline 2 ml in group S and NP at 3-21 d after CCI.Mechanical and thermal pain threshold were measured by paw withdrawal latencies to run Frey hair and radiant heat stimulation at 1 d before and 3,7,14,21 d after CCI.Four animals were killed at 1 d before (baseline) and 7,14 and 21 d after CCI following the measurement of pain threshold in each group and the L4.5 segments of the spinal cord were removed for determination of P2X4 R mRNA expression by RT-PCR.Results There was no significant change in thermal and mechanical paln threshold and P2X4 R mRNA expression in the spinal cord after CCI in group S ( P > 0.05),while thermal and mechanical pain threshold was reduced,and P2X4 R mRNA expression was up-regulated in the other four groups as compared with the baseline values (P < 0.05 ).Thermal and mechanical pain threshold was significantly higher and P2X4 R mRNA expression in the spinal cord lower after CCI in group K,CL and KC than in group NP ( P < 0.05 ).Thermal and mechanical pain threshold was significantly higher and P2X4 R mRNA expression lower after CCI in group KC than in group K ( P < 0.05),but no significant difference was found in the above parameters between group CL and K ( P > 0.05).Conclusion Both ketamine and clonidine can alleviate neuropathic pain via down-regulating the expression of P2X4 R mRNA in the spinal cord in a rat model of neuropathic pain.

Objective To investigate the effects of ketamine preconditioning on the expression of induced nitric oxide synthase(iNOS)mRNA after myocardial ischemia-reperfusion injury induced by cardiopulmonary bypass(CPB)in patients with congenital heart disease(CHD).Methods Thirty-six patients with atrial or ventrieular septal defect were randomly allocated to 3 groups(n=12):control group and ketamine preconditioning group(K1 group,K2 group).Ketamine 0.5 mg/kg and 1.0 mg/kg,were injected at the time of sternum splitted,aorta intubated and before 5 minutes of aorta clamped off intravenously.Collected the myocardium at the time of superior vena cava intubated(T1),30 minutes after aorta clamped on(T2)and 30 minutes after aorta clamped off(T3).Detected the value of iNOS mRNA in myocardium by one-step real time fluorescence quantitative RT-PCR.Results The levels of iNOS mRNA were significantly increased at T2 and T3 as compared with T1 in the three groups,and were significantly lower both in K1 group(2.33±0.31,3.76±0.61)and K2 group(1.92±0.12,3.12±0.39)than those in control group(2.85±0.48,4.49±0.86)(P＜0.01 or ＜0.05).Furthermore,they were lower in K2 group than those in K1 group(P＜0.05).Conclusion Ketamine can significantly decrease iNOS mRNA in myocardium,and decrease the plasma marker of cardiac muscle injury,it shows dose dependent.

Objective To investigate the protective effects of pretreatment with low-dose ketamine on intestinal mueosa against ischemia-reperfasion injury (I/R) and the underlying mechanism. Methods Forty-eight male SD rats weighing 230-270 g were randomly divided into 6 groups (n = 8 each) : group Ⅰ sham operation (S) ;group Ⅱ ketamine + sham operation (KS);group Ⅲ l/R;group Ⅳ ketamine + I/R (K);groupⅤ ketamine + ZnPPⅨ + I/R (KZ) and group Ⅵ ZnPPⅨ + I/R. Ketaminc 10 mg/kg and/or ZnPPⅨ 5 mg/kg were injected intraperitoneally 30 min before I/R in group Ⅳ, Ⅴ and Ⅵ. Intestinal I/R was produced by clamping of superior mesentery artery for 1 h followed by 6 h reperfusion. The animals were then killed and a segment of small intestine of 2 cm in length at about 10 cm from ileocecal valve was removed for determination of MDA content and SOD activity, HO-1 and iNOS expression and histological examination. The degree of intestinal tissue damage was graded using Chiu's scoring system (0 = normal, 5 = severe damage-exfoliation of villi, disruption of proper lamina, bleeding and ulceration). Results Intestinal MDA content was significantly increased, SOD activity was decreased and HO-1 and iNOS expression was significantly up-regulated by I/R (group Ⅲ) as compared with group Ⅰ and Ⅱ . Ketamine pretreatment significantly attenuated I/R-induced increase in MDA content and decrease in SOD activity and the protective effects of ketamine against I/R were counteracted by concomitant asministration of ZnPPⅨ. Microscopic examination showed that the pathological changes induced by I/R were significantly attenuated by ketamine and the protective effects of ketamine pretreatment against I/R were reversed by ZnPPⅨ in group Ⅴ. Conclusion Low-dose ketamine pretreatment can significantly ameliorate intestinal ischemia-reperfusion injury and up-regulation of intestinal HO-1 expression and down-regulation of iNOS are involved in the mechanism.

Objective To investigate the protective effect of pyrrolidine dithiocarbamate (PDTC) pretreatment on lung agaillst LPS-indueed injury in rats.Methods Fifty-four Wistar rats of both sexes weighing 180-220 g were randomly idivided into 3 groups:group I normal control(group C,n=6);group Ⅱ LPS (group L,n=24)and group Ⅲ PDTC(group P,n=24).Endotoxemia was induced by intraperitoneal LPS 8 mg/kg in group Ⅱ and Ⅲ.In group Ⅲ PDTC 120 mg/kg was injected iv at 30 min before IP LPS.Venous blood samples were collected at 1,3,6 and 12 h after LPS administration in group L and P and after normal saline administration in group C for determination of serum IL-6 concentration by ELISA.Six animals were killed at each time point after blood sample collection.The lungs were removed for microscopic examination and determination of W/D lung weight ratio,HSP70 expression and NF-κB activity.Results Intraperitoneal LPS significantly increased serum IL-6 concentration and W/D lung weight ratio,HSP70 expression and NF-κB activity in group Ⅱ.PDTC pretreatment significantly attenuated LPS-induced increase in serum IL-6 concentration,W/D lung weight ratio andNF-κB activity.The lung histologic dalnage induced by LPS Wag also ameliorated by pretreatment with PDTC.Conclusion Pyrrolidine dithiocarbamate pretreatment Can protect lung against LPS-induced injury through inhibition of activation of lung tissue NF-κB and up-regulation of expression of HSP70.

Objective To investigate the effect of postconditioning with propofol and ischemia on the hepatic ischemia-reperfusion (I/R) injury in rats. Methods Thirty male SD rats weighing 200-250 g were randomly divided into 5 groups of 6 animals each: group I sham operation (group S); groupⅡ I/R; group Ⅲ ischemic postconditioning (group IPC); group Ⅳ propofol postconditioning (group PPC) and group V IPC + PPC. In group Ⅱ-Ⅳ the hepatic arteries and veins of middle and left lobes were occluded for 1 h followed by 4 h reperfusion. Ischemia of the liver was confirmed by the color of the liver turning from red to gray. In group Ⅲ and Ⅴ the livers were subjected to six episodes of 10 s ischemia at 10 s intervals at the end of 1 h ischemia before 4 h reperfusion. In group Ⅳ and V 0.5 % propofol 10 mg/kg was given iv at the end of ischemia followed by propofol infusion at 40 mg·g~(-1) ·h~(-1). Blood samples were taken at the end of 4 h reperfusion for determination of serum ALT activity. Mean-while liver specimens were taken for electron microscopic examination and determination of MDA content and SOD activity. Results I/R significantly increased serum ALT activity and MDA content in the liver and decreased liver SOD activity in group Ⅱ . The I/R-induced changes were significantly attenuated by propofol and/or ischemic postconditioning in group Ⅲ ,Ⅱ and Ⅴ . I/R significantly increased Bel-2 and Bax protein expression in the liver cells. Propofol and/or ischemic postconditioning increased Bel-2 protein expression further but decreased Bax protein expression in group Ⅲ , Ⅳ and Ⅴ as compared with group Ⅱ (group I/R).Electron microscopic examination showed that the pathologic changes induced by I/R were less severe in group Ⅲ, Ⅳ and Ⅴ than in group I/R. Conclusion Postconditioning with propofol and ischemia can reduce the hepatic I/R injury and the mechanism may be related to inhibition of lipid peroxidation and apoptosis, but the efficacy is the same as that of propofol postconditioning alone.

Objective To evaluate the effect of intraperitoneal (IP) clonidine on the expression of GAP-43 mRNA in the spinal cord in a rat model of chronic neuropathic pain. Methods Thirty-six male SD rats weighing 180-220 g were randomly assigned to one of 3 groups (n=12 each) : group Ⅰsham operation (S); group Ⅱ chronic constriction injury (CCI) and group Ⅲ tP clonidine + CCI (CL). The animals were anesthetized with IP 10% chloral hydrate 300 mg/kg. The right sciatic nerve was exposed and 4 ligatures were placed in group CCI and CL. Clonidine 1 mg/kg was given IP immediately after surgery in group CL. Paw-withdrawal threshold (PWT) to thermal and von Frey filament stimulation was measured before (T_0, baseline) and at 3, 7 and 14 days after surgery (T_(1-3)). The animals were then killed. The lumbar segment of the spinal cord was removed for determination of the expression of GAP-43 mRNA. Results The PWT to thermal and mechanical stimulation was significantly reduced at 3 days after surgery (T_1) in group CCI and CL as compared with group S, and was significantly higher at T_2 and T_3 in group CL than in group CCI. The GAP-43 mRNA expression in the spinal cord was significantly increased in group CCI and CL as compared with group S and significantly lower in group CL than in group CCI. Conclusion lntraperitoneal clonidine can inhibit hyperalgesia by reducing the expression of GAP-43 mRNA in the spinal cord in a rat model of chronic neuropathic pain.

Objective To investignte the effects of ambroxol on lung injury in children undergoing cardiac surgery with cardiopulmonary bypass (CPB).Methods Thirty-six ASA Ⅱ or Ⅲ children of both sexes aged≤8 yr,weighing≤25 kg undergoing repair of ventricular septal defect (VSD) under CPB were randomly divided into 3 groups (n=12 each):I control group (C);II low dose ambroxol group (2.25 mg/kg) (A,) and III moderate dose ambroxol group (4.50 mg/kg) (A2).Ambrexol was diluted with normal saline 10 ml and infused slowly after skin incision in group A1 and A2.In group C equal volume of normal saline(10 ml) was infused instead of ambroxol.Blood samples were taken from radial artery before skin incision,at 20 rain of CPB,20 rain after aortic unclamping,2 h and 6 h after temtination of CPB and 12 h after operation for determination of plasma MDA concentration and SOD activity and blood gas analysis.Respiratory index (RI) and pulmonary compliance (CL)were calculated.Results The plasma MDA concentration and RI were significantly lower while plasma SOD activity was significantly higher in group A2 than in group C and A1·CL was significantly higher in group A2 than in group C.Conclusion Ambroxol 4.50 mg/kg can attenuate lung injury in children undergoing cardiac surgery with CPB by decreasing lipid peroxidation.

Objective To evaluate the effect of dexmedetomidine and small dose of ketamine on the expression of P2X4 receptor (P2X4 R) mRNA and P2X7 receptor (P2X7R) mRNA in the dorsal root ganglion of rats with neuropathic pain.Methods Ninety male Sprague-Dawley rats,aged 6-9 weeks,weighing 180-220 g,were randomly divided into 5 groups (n =18 each):sham group (group S),chronic constrictive injury group (group CCI),dexmedetomidine group (group D),ketamine group (group K) and dexmedetomidine + ketamine group (group DK).The animals were anesthetized with intraperitoneal 10％ chloral hydrate 400 mg/kg.Neuropathic pain was induced by CCI in CCI,D,K and DK groups.The sciatic nerve was exposed and 4 loose ligatures were placed on the sciatic nerve at 1mmintervals with 4-0 silk thread.In group S,the sciatic nerves were only exposed but not ligated.In D,K and DK groups,dexmedetomidine 50μg/kg,ketamine 10 mg/kg and dexmedetomidine 25μg/kg + ketamine 5 mg/kg were injected intraperitoneally,respectively,while the equal volume of normal saline was injected in S and CCI groups,once a day for 14 consecutive days after CCI.Mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before CCI,and 3,7 and 14 days after CCI.Six animals were sacrificed after measurement of pain threshold at 3,7 and 14 days after CCI and the lumbar segments (L4-6) of the dorsal root ganglion were removed for determination of P2X4 R mRNA and P2X7 R mRNA expression by RT-PCR.Results Compared with group S,MWT and TWL were significantly decreased at 3,7 and 14 days after CCI in groups CCI,D,K and DK,the expression of P2X4R mRNA and P2X7R mRNA was up-regulated at 3,7 and 14 days after CCI in groups CCI,D and K,and the expression of P2X4 R mRNA and P2X7 R mRNA was up-regulated at 3 and 7 days after CCI in group DK (P ＜ 0.05).Compared with group CCI,TWL and MWT were significantly increased and the expression of P2X4 R mRNA and P2X7 R mRNA was down-regulated at 3,7 and 14 days after CCI in groups D,K and DK (P ＜ 0.05).Compared with D and K groups,TWL and MWT were significantly increased and the expression of P2X4 R mRNA and P2X7 R mRNA was down-regulated at 3,7 and 14 days after CCI in group DK (P ＜ 0.05).Conclusion The mechanism by which the combination of dexmedetomidine and small dose of ketamine produces a synergistic antinociception in rats with neuropathic pain may be related to down-regulation of the expression of P2X4 R mRNA and P2X7 R mRNA.

Objective To investigate the effect of dexmedetomidine on the expression of purinergic P2X4 receptor (P2X4R) mRNA and p38 mitogen-activated protein kinase (p38 MAPK) mRNA in spinal cord in a rat model of neuropathic pain (NP).Methods Seventy-two male SD rats weighing 180-220 g were randomly assigned into 3 groups ( n =24 each):sham operation group (group S),group NP and dexmedetomidine group ( group DEX).The animals were anesthetized with intraperitoneal 10％ choral hydrate 350 mg/kg.NP was induced by chronic constrictive injury (CCI).The right sciatic nerve was exposed and 4 ligatures were placed on sciatic nerve at 1 mm intervals with 4-0 silk thread in groups NP and DEX.In group S,the right sciatic nerve was only exposed but not ligated.Dexmedetomidine 50μg/kg was injected intraperitoneally daily staring from the end of operation,while the equal volume of normal saline was injected in groups S and NT.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured on day 1 before operation and on day 1,3,7 and 14 after operation.Six animals were sacrificed after MWT and TWL measurement on day 1,3,7 and 14 after operation in each group,the L4～6 segment of spinal cords was removed for determination of P2X4 R mRNA and p38 MAPK mRNA expression by RT-PCR.Results Compared with group S,MWT and TWL were significantly decreased and the expression of P2X4 R mRNA and p38 MAPK mRNA was significantly up-regulated after operation in groups NP and DEX ( P ＜0.05).Compared with group NP,TWL and MWT were significantly increased and the expression of P2X4 R mRNA and p38 MAPK mRNA was significantly down-regulated after operation in group DEX ( P ＜ 0.05 ).TWL and MWT were significantly higher and the expression of P2X4 R mRNA and p38 MAPK mRNA was significantly lower on day 1,3 and 14 after operation than on day 7 after operation in groups NiP and DEX ( P ＜ 0.05).Conclusion The mechanism by which dexmedetomidine attenuates NP is related to inhibition of the expression of P2X4 R mRNA and p38 MAPK in rats.