Objective To evaluate the relationship between endoplasmic reticulum stress and cell apoptosis during liver cold ischemia-reperfusion(I/R)in rats. Methods Thirty-two SPF healthy adult male Sprague-Dawley rats,weighing 200-250 g,were divided into 2 groups(n=16 each)using a random number table:sham operation group(group S)and liver cold I/R group(group I/R).In group I/R,the liver was perfused through the portal vein with 4 ℃ lactated Ringer′s solution 6-8ml/min for 30min after liver ischemia,and the liver blood flow was restored after the end of perfusion. At 6 h of reperfusion in group I/R or at 6 h after peritoneum closure in group S,blood samples from the inferior vena cava were collected for determination of serum alanine transaminase and aspartate transaminase concentrations. After blood sampling,liver tissues were obtained for examination of pathological changes and for determination of malondialdehyde content(by thiobarbituric acid method),superoxide dismutase activity(using xanthine oxidase method),cell apoptosis(using TUNEL),expression of endoplasmic reticulum protein 46(ERP46),immunoglobulin heavy chain binding protein(BiP)and caspase-12(by immunohistochemistry),and expression of ERP46,BiP and caspase-12 mRNA(using quantitative real-time polymerase chain reaction).The pathological changes were scored. Apoptosis rate was calculated. Results Compared with group S,the serum alanine transaminase and aspartate transaminase concentrations,pathological scores,malondialdehyde content and apoptosis rate were significantly increased,the activity of superoxide dismutase was decreased,and the expression of ERP46,BiP and caspase-12 protein and mRNA was up-regulated in group I/R(P<0.05).Conclusion The mechanism of cell apoptosis during liver cold I/R may be related to excessive activation of endoplasmic reticulum stress in rats.

Objective To evaluate the effect of hydrogen on the endoplasmic reticulum stress during liver cold ischemia-reperfusion (I/R) in rats.Methods Twenty-four SPF healthy adult male Sprague-Dawley rats,weighing 200-250 g,were divided into 3 groups (n=8 each) using a random number table:sham operation group (group S),liver cold I/R group (group I/R) and hydrogen-saturated lactated Ringer's solution group (group HL).After occlusion of the liver blood flow,livers were perfused through the portal vein with 4 ℃ hydrogen-saturated lactated Ringer's solution 6-8 ml/min for 30 min.The liver blood flow was restored after the end of perfusion.At 6 h of reperfusion in I/R and HL groups or at 6 h after peritoneum closure in group S,blood samples from the inferior vena cava were collected for determination of serum alanine transaminase (ALT) and aspartate transaminase (AST) concentrations.After blood sampling,liver tissues were obtained for examination of pathological changes and for determination of cell apoptosis (using TUNEL),malondialdehyde (MDA) content (by thiobarbituric acid method),superoxide dismutase (SOD) activity (using xanthine oxidase method),expression of endoplasmic reticulum protein 46 (ERP46),immunoglobulin heavy chain binding protein (BiP) and caspase-12 (by immunohistochemistry),and expression of ERP46,BiP and caspase-12 mRNA (using quantitative real-time polymerase chain reaction).The pathological changes were scored.Apoptosis rate was calculated.Results Compared with group S,the serum ALT and AST concentrations,pathological scores,apoptosis rate and MDA content were significantly increased,the SOD activity was decreased,and the expression of ERP46,BiP and caspase-12 protein and mRNA was up-regulated in I/R and HL groups (P＜0.05).Compared with group I/R,the serum ALT and AST concentrations,pathological scores,apoptosis rate and MDA content were significantly decreased,the SOD activity was increased,and the expression of ERP46,BiP and caspase-12 protein and mRNA was down-regulated in group HL (P＜0.05).Conclusion The mechanism by which hydrogen reduces cell apoptosis may be related to inhibition of endoplasmic reticulum stress during liver cold I/R in rats.

As an important protein molecule for innate immunity,Toll-like receptor 7 (TLR7) is also a bridge between innate immunity and adaptive immunity.When TLR7 is activated,it can exert its effect on liver diseases through different signaling pathways.Studies on the role and application of TLR7 agonist in liver diseases are increasing in recent years.This article reviewed the research on TLR7 agonist in liver diseases.

Objective To evaluate the effect of Toll-like receptor 7 (TLR7) agonist on c-Jun Nterminal kinase (JNK) signaling pathway during liver injury in the septic mice.Methods One hundred eighty pathogen-free adult male C57BL/6 mice,aged 10-14 weeks,weighing 20-26 g,were randomly divided into 3 groups (n=60 each) using a random number table:sham operation group (group S);sepsis group (group Sep);TLR7 agonist group (group GDQ).Sepsis was induced by cecum ligation and puncture.In group GDQ,TLR7 agonist 1.5 g/kg was injected intraperitoneally at 24 h before establishment of the model.At 6,12 and 24 h after operation,10 mice in each group were sacrificed,and the livers were removed to detect the expression of interleukin-6 (IL-6) and IL-10 by Western blot.The expression of JNK was determined by immuno-histochemistry,and the histopathologic changes of livers were examined with a light microscope at 24 h after operation.The survival of mice was observed at 14 days after operation,and the 14-day survival rates were calculated.Results Compared with group S,the 14-day survival rates were significantly decreased,and the expression of IL-6,IL-10 and JNK was significantly up-regulated at 6,12 and 24 h after operation in Sep and GDQ groups (P＜0.05).Compared with group Sep,the 14-day survival rates were significantly increased,and the expression of IL-6,IL-10 and JNK was significantly down-regulated at 6,12 and 24 h after operation in group GDQ (P＜0.05).The pathological changes of livers were significantly attenuated in group GDQ as compared with group Sep.Conclusion TLR7 agonist can reduce the liver injury through blocking the JNK signaling pathway in the septic mice.

Objective To evaluate the changes in natural Killer (NK) cell subsets definetd by CD11b and CD27 in the spleen of septic mice.Methods A total of 168 pathogen-free healthy male C57BL/6 mice,weighing 20-30 g,aged 8-10 weeks,were divided into 2 groups (n=84 cach) using a random number table:sham operation group (Sham group) and sepsis group (Sep group).Sepsis was induced by cecal ligation and puncture in chloral hydrate-anesthetized mice.Thirty mice in each group were selected to assess the survival within 4 days after operation,and the survival rate was calculated.At 2,4,6,24,48 and 72 h after operation (T1-6),6 mice were randomly selected,and blood samples were taken from the eyeballs for determination of serum tumor necrosis factor-alpha and interleukin-10 concentrations by enzyme-linked immunosorbent assay.Six mice were randomly selected at T4-6 and sacrificed,and the spleens were removed for measurement of the percentage of NK cells and their subsets by flow cytometry.Results Compared with Sham group,the survival rate was significantly decreased at different time points,the serum necrosis factor-alpha concentration at T1-3,6 and serum interleukin-10 concentration at T3-6 were increased,the percentage of NK cells was decreased at T4-6,the percentage of CD27-CD11b+NK cells was decreased and the percentage of CD27+CD11b+ and CD27+CD11b-NK cells was increased at T5,the percentage of CD27-CD11b-NK ceils was decreased at T4,5,and the percentage of CD27-CD11b-NK cells was increased at T6 in Sep group (P＜0.05).Conclusion Changes in NK cell subsets defined by CD11b and CD27 in the spleen play an important role in the development of sepsis in mice.

Objective To evaluate the role of necroptosis in liver injury in septic rats.Methods Twenty-four SPF healthy male adult Sprague-Dawley rats,weighing 200-220 g,aged 6-8 weeks,were divided into 3 groups (n=8 each) using a random number table:sham operation group (Sh group),sepsis group (Sep group) and specific necroptosis inhibitor necrostatin-1 group (N group).Sepsis was induced by cecal ligation and puncture in anesthetized rats in N and Sep groups.Necrostatin-1 1.0 mg/kg was intravenously injected at 1 h before operation in group N,while the equal volume of dimethyl sulfoxide was given instead in group Sep.Rats were sacrificed at 6 h after operation,and livers were removed for examination of the pathological changes (with a light microscope) and for determination of the level of reactive oxygen species (ROS) in liver tissues (by using chemiluminescence assay) and expression of receptor-interacting protein kinase-1 (RIPK1),RIPK3,mixed lineage kinase domain-like (MLKL) and high-mobility group box 1 protein (HMGB1) in liver tissues (using Western blot).Results Compared with Sh group,the ROS level in liver tissues was significantly increased,and the expression of RIPK1,RIPK3,MLKL and HMGB1 in liver tissues was up-regulated in Sep and N groups (P＜0.05).Compared with Sep group,the ROS level in liver tissues was significantly decreased,and the expression of RIPK1,RIPK3,MLKL and HMGB 1 in liver tissues was down-regulated in group N (P＜0.05).The pathological changes of liver tissues were significantly attenuated in group N when compared with group Sep.Conclusion Neeroptosis is involved in liver injury in septic rats.

Objective To evaluate the effect of dexmedetomidine on necroptosis during liver injury in septic rats.Methods Eighteen SPF adult male Sprague-Dawley rats,weighing 200-220 g,were divided into 3 groups (n=6 each) using a random number table:sham operation group (group SH),sepsis group (group SEP) and dexmedetomidine group (group DEX).Sepsis was induced by cecal ligation and puncture in chloral hydrate-anesthetized rats in SEP and DEX groups.Dexmedetomidine 5 μg/kg was injected via the caudal vein at 1 h before operation in group DEX.Blood samples were collected from the caudal vein at 6 h after operation for determination of serum aspartate amino-transferase (AST) and alanine aminotransferase (ALT) concentrations.The rats were then sacrificed and livers were removed for determination of the level of reactive oxygen species (ROS) in liver tissues (using chemiluminescence assay) and expression of receptor-interacting protein 1 (RIP1),RIP3,mixed lineage kinase domain-like (MLKL),high-mobility group box 1 protein (HMGB1) and dynamin-related protein 1 (Drpl) in liver tissues (by Western blot).Results Compared with group SH,the serum AST and ALT concentrations were significantly increased,the expression of RIP1,RIP3,MLKL,HMGB1 and Drpl in liver tissues was up-regulated,and the level of ROS in liver tissues was increased in SEP and DEX groups (P＜0.05).Compared with group SEP,the serum AST and ALT concentrations were significantly decreased,the expression of RIP1,RIP3,MLKL,HMGB1 and Drp1 in liver tissues was down-regulated,and the level of ROS in liver tissues was decreased in group DEX (P＜0.05).Conclusion The mechanism by which dexmedetomidine attenuates liver injury may be related to inhibition of necroptosis in septic rats.

Objective To evaluate the changes in the expression of transient receptor potential vanilloid 1 (TRPV1) in dorsal root ganglions (DRGs) during remifentanil-induced hyperalgesia in the rats with incisional pain.Methods Thirty-two SPF healthy male Sprague-Dawley rats,weighing 240-260 g,aged 2-3 months,in which caudal catheters were successfully implanted,were divided into 4 groups (n=8 each) using a random number table:control group (group C),incisional pain group (group Ⅰ),remifentanil group (group R),and incisional pain + remifentanil group (group I+R).A 1 cm longitudinal incision was made through skin,fascia and muscle of the plantar aspect of the left hindpaw to establish the model of incisional pain.In group R,remifentanil was intravenously infused for 60 min at a rate of 1.2 μg · kg-1 · min-1.In group Ⅰ,the model of incisional pain was established,and the equal volume of normal saline was intravenously infused for 60 min at the same time.In group I+R,the model of incisional pain was established,and remifentanil was intravenously infused for 60 min at a rate of 1.2 μg · kg-1 · min-1 at the same time.In group C,the equal volume of normal saline was intravenously infused for 60 min.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawl latency (TWL) were measured at 24 h before normal saline or remifentanil infusion (To) and 2,6,24 and 48 h after the end of infusion (T1-4).The rats were sacrificed after the last measurement of pain threshold,and the DRGs of the lumbar segment (L4-6) were removed for determination of the expression of TRPV1 protein and mRNA by Western blot and real-time polymerase chain reaction,respectively.Results Compared with group C,the MWT was significantly decreased,and the TWL was shortened at T1-4,and the expression of TRPV1 protein and mRNA was up-regulated in R,I and I+R groups (P＜0.05).Compared with group R or group I,the MWT was significantly decreased,and the TWL was shortened at T1-4,and the expression of TRPV1 protein and mRNA was up-regulated in group I+R (P＜0.05) Conclusion Up-regulated expression of TRPV1 in DRGs may be involved in the mechanism underlying remifentanil-induced hyperalgesia in the rats with incisional pain.

Objective To evaluate the efficacy of different low-doses of nalmefene in preventing remifentanil-induced postoperative hyperalgesia. Methods One hundred American Society of Anesthesiolo-gist physical status Ⅰor Ⅱpatients, aged 20-64 yr, wih body mass index of 18-25 kg∕m2, scheduled for elective gynecological laparoscopic surgery under general anesthesia, were divided into 4 groups(n=25 each)using a random number table: control group(group C)and different doses of nalmefene groups (N1, N2 and N3 groups). In N1, N2 and N3 groups, nalmefene 02, 03 and 05 μg∕kg(diluted to 5 ml in normal saline)were intravenously injected, respectively, at 5 min before anesthesia induction, while the equal volume of normal saline was given in group C. Anesthesia was induced with midazolam 005 mg∕kg, sufentanil 03 μg∕kg, etomidate 03 mg∕kg and rocuronium 06 mg∕kg. The patients were me-chanically ventilated after tracheal intubation. Anesthesia was maintained by IV infusion of remifentanil 03 μg·kg-1·min-1and inhalation of 4%-6% desflurane, bispectral index value was maintained at 45-60, and muscle relaxation was maintained with intermittent IV boluses of rocuronium. After admission to postan-esthesia care unit, patient-controlled analgesia(PCA)was performed, and PCA solution contained sufen-tanil 1 μg∕ml in 100 ml of normal saline. PCA pump was programmed to deliver a 05 ml bolus dose with a lockout interval of 15 min and background infusion at 2 ml∕h. Numeric rating scale score was maintained <4. The time for remifentanil infusion was recorded. The consumption of sufentanil was recorded in 0-1, 1-3, 3-6, 6-12 and 12-24 h periods after surgery, and the occurrence of nausea, vomiting, tachycardia, hypertension and shivering was also recorded within 24 h after surgery. Results Compared with group C, the postoperative consumption of sufentanil was significantly reduced in 0-1 h and 1-3 h periods after sur-gery in group N1 and in 0-1, 1-3, 3-6 and 6-12 h periods after surgery in group N2, and the incidence of postoperative nausea was significantly decreased in N1, N2 and N3 groups(P<005). The consumption of sufentanil in 3-6 h period after surgery was significantly lower in group N2 than in group N1(P<005). Conclusion The optimal dose of nalmefene is 03 μg∕kg when used to prevent remifentanil-induced post-operative hyperalgesia.

Objective To evaluate the changes in the expression of artemin in skin around the inci-sion during remifentanil-induced hyperalgesia in the rats with incisional pain. Methods Thirty-two healthy male Sprague-Dawley rats, aged 10-12 weeks, weighing 250-280 g, were divided into 4 groups (n = 8 each) using a random number table: control group (group C), incisional pain group (group I), remifen-tanil group (group R) and incisional pain plus remifentanil group (group I+R). Remifentanil was intrave-nously infused for 60 min at a rate of 1 μg·kg-1 ·min-1 in group R. In group I, the model of incisional pain was established, and the equal volume of normal saline was infused for 60 min via the tail vein at the same time. In group I+R, the model of incisional pain was established, and remifentanil was infused for 60 min via the tail vein at a rate of 1 μg·kg-1 ·min-1 at the same time. The equal volume of normal saline was infused for 60 min via the tail vein in group C. Mechanical paw withdrawal threshold (MWT) and ther-mal paw withdrawal latency (TWL) were measured at 24 h before infusion of remifentanil or normal saline and 2, 6, 24 and 48 h after the end of infusion (T0-4 ). Rats were sacrificed following the last measurement of pain threshold, and ipsilateral plantar skin was removed for detection of the expression of artemin protein and mRNA (by fluorescent quantitative real-time polymerase chain reaction or Western blot). Results Compared with group C, MWT was significantly decreased and TWL was shorten at T1-4 , and the expression of artemin protein and mRNA in plantar skin was up-regulated in R, I and I+R groups (P<0. 01). Compared with R and I groups, MWT was significantly decreased and TWL was shorten at T1-4 , and the ex-pression of artemin protein and mRNA in plantar skin was up-regulated in group I+R (P<0. 01). Conclu-sion The peripheral mechanism by which remifentanil induces hyperalgesia may be related to up-regulated expression of artemin in skin around the incision in the rats with incisional pain.