Objective To evaluate the role of MCP/DAF expression in the spinal cord in the development of neuropathic pain (NP) induced by chronic constrictive injury (CCI) of the sciatic nerve in rats.Methods Twenty-four Sprague-Dawley rats transfected with MCP/DAF,weighing 200-250 g,were randomly divided into 2 groups (n =12 each) using a random number table:sham operation of transfected rat group (Rsham group) and CCI of transfected rat group (RCCI group).Twenty-four healthy male Sprague-Dawley rats,weighing 200-250 g,were randomly divided into 2 groups (n =12 each) using a random number table:sham operation of normal rat group (Nsham group) and CCI of normal rat group (NCCI group).The right sciatic nerve was exposed and 4 loose ligatures wen placed on the sciatic nerve at 1 mm intervals with 4-0 catgut in RCCI and NCCI groups.The right sciatic nerve was only exposed in Rsham and Nsham groups.Paw withdrawal threshold to yon Frey filament stimulation (PWT) and paw withdrawal latency to nociceptive thermal stimulation (PWL) were measured at 1 day before operation (baseline) and 1,3 and 7 days after operation.The animals were sacrificed after measurement of pain threshold on 7 days after operation and the L4,5 segment of the spinal cord was removed for determination of the expression of OX-42 (by immuno-histochemistry) and MCP mRNA and DAF mRNA (by RT-PCR).Results Compared with Nsham group,the PWT and PWL were significantly decreased on 1,3 and 7 days after operation,the expression of OX-42 was up-regulated,and the expression of MCP mRNA and DAF mRNA was down-regulated in NCCI group (P ＜ 0.05),and no significant changes were found in the PWT and PWL on 1,3 and 7 days after operation and expression of OX-42(P ＞ 0.05),and the expression of MCP mRNA and DAF mRNA was up-regulated in Rsham and RCCI groups (P ＞ 0.05).Compared with NCCI group,the PWT and PWL were significantly increased on 1,3 and 7 days after operation,the expression of OX-42 was down-regulated,and the expression of MCP mRNA and DAF mRNA was up-regulated in RCCI group (P ＜ 0.05).Conclusion Up-regulation of MCP/ DAF expression in the spinal cord can inhibit the development of NP in rats and regulation of activation of microglias in the spinal cord is involved in the mechanism.

Objective To investigate microRNAs ( miRNAs) expression profiling of cardiomyocytes in rats with heart failure, and predict miRNAs-regulated target genes and their functions.Methods Total of 18 male SD rats weighing 200-220 g were randomly divided into 2 groups:the control group ( CON) and the heart failure group (HF).The rats in HF group were injected by adriamycin via tail vein to induce heart failure, meanwhile in CON group, rats were received an equal volume of 0.9% sodium chloride intravenously.The cardiomyocytes isolated from the rat hearts in two groups and cultured overnight.After that, total RNA was extracted and then subjected to miRNA microarray to screen differentially expressed miRNAs.The reults of microarray were further verified by quantitative real-time PCR ( qRT-PCR ) .The target genes regulated by differentially expressed miRNAs were predicted by the software of Targetscan and miRanda.Bioinformatics analysis was performed to predict the miRNAs-regulated target genes and analyze the enriched gene ontology ( GO) and signaling pathway ( KEGG Pathway) .Results The results of miRNA microarray showed that a total of 37 miRNAs were differentially expressed in HF group as compared to CON group, among which 22 miRNAs were up-regulated and 15 miRNAs were down-regulated (P<0.01, FDR<0.05).The expression of miR-133b-5p (t=14.56, P<0.01), miR-6216 (t=9.32, P<0.01) and let-7e-5p (t=13.92, P<0.01) which were detected by qRT-PCR exhibited the similar tendency of up or down regulation to those shown in microarray results.Bioinformatics analysis indicated that miRNAs-regulated target genes were significantly enriched in 31 GOs (P<0.01, FDR<0.05) and 12 signal pathways (P<0.05, FDR<0.05), among which ubiquitin-proteasome system, MAPK signaling pathway and Toll like siganling pathway exhibited a higher enrichment. Conclusion MiRNA expression profile on cardiomyocytes in rat with adriamycin-induced heart failure was significantly changed.These differentially expressed miRNAs might participate in the process of heart failing by regulating their target genes in rat cardiomyocytes.

Objective To evaluate the effects of morphine preconditioning on the expression of microRNAs (miRNAs) during hypoxia-reoxygenation (H/R) in isolated cardiomyocytes in rats with heart failure.Methods Healthy adult male Sprague Dawley rats,w eighing 200-220 g,were used in this study.Adriamycin 2.0 mg/kg was injected once a week for 6 weeks via the tail vein to induce heart failure.The cardiomyocytes were isolated from the failing hearts of rats and seeded in 24-well plates or in 60 mm diameter dishes.The cells were then randomly divided into 3 groups (n =16 each) using a random number table:control group (group C); group H/R;morphine preconditioning group (group MP).The cells were cultured in normal culture atmosphere in group C.After being exposed to hypoxic air (5％ CO2-95％ N2) for 90 min,the cells were returned to the high-glucose DMEM supplemented with 10％ newborn bovine serum and were then cultured for 120 min in H/R and MP groups.In group M,the cells were cultured in morphine culture medium (final concentration of morphine 0.3 μmol/L) for 10 min and then were returned to the culture medium without morphine and cultured for 30 min immediately before hypoxia.At 120 min of reoxygenation,the cells of 8 wells in each group were chosen to detect the cell viability and lactate dehydrogenase (LDH) activity (by Typan blue staining).All the RNAs were extracted from the cardiomyocytes of the left 8 wells in each group and subjected to miRNA microarray to screen differentially expressed miRNAs.Results The cell viability was significantly lower,the activity of LDH was higher,the expression of miR-6216 and let7e-5p was higher,and the expression of miR-133b-5p was lower in H/R and MP groups than in group C (P ＜ 0.05).Compared with H/R group,the cell viability was significantly increased,the activity of LDH was decreased,the expression of miR-133b-5p was up-regulated,and the expression of miR-6216 and let-7e-5p was down-regulated in MP group (P ＜ 0.05).Conclusion Morphine preconditioning reduces H/R injury to isolated cardiomyocytes in rats with heart failure through regulating the expression of miRNAs such as miR133b-5p,miR-6216 and let-7e-5p.

Objective To evaluate the role of opioid receptors and phosphatidylinositol 3-kinase/proteinserine-threonine kinases (PI3K/Akt) and extracellular signal-regulated kinase (ERK) signaling pathways in reduction of hypoxia/reoxygenation (H/R)-induced injury to cardiomyocytes by remifentanil preconditioning in rats.Methods Primary cardiomyocytes were obtained from adult male Sprague-Dawley rats and cultured in DMEM culture medium.The cells were seeded in 48-well plates (density 2 × 104 cells/ml,500 μl/well) and randomly divided into 12 groups (n =9 each):control group (group C),group H/R,hypoxia preconditioning group (group HPC),remifentanil preconditioning (RPC) group,naltrindole (δ receptor antagonist) + RPC group,nor-binaltorphimine (κ receptor antagonist) + RPC group (BNI + RPC group),wortmannin (PI3K inhibitor) + RPC group (W+ RPC group),PD98059 (ERK inhibitor) + RPC group (PD + RPC group),NTD group,BNI group,W group and PD group.In group H/R,the cardiomyocytes were exposed to 90 min of hypoxia,followed by 120 min of reoxygenation.In group HPC,the cardiomyocytes were exposed to 10 min of hypoxia,followed by 30 min of reoxygenation before H/R.In group RPC,the cardiomyocytes were preconditioned with remifentanil with the final concentration of 1 μmol/L for 10 min,followed by 30 min routine culture before H/R.In NTD + RPC,BNI + RPC,W + RPC and PD + RPC groups,naltrindole 5μmol/L (final concentration),nor-binaltorphimine 5 μmol/L (final concentration),wortmannin 0.1 μmol/L (final concentration) and PD98059 30μmol/L (final concentration)were added,respectively,and then the cells were coincubated with remifentanil for 10 min,followed by 30 min routine culture before H/R.The viability of cardiomyocytes,cell apoptosis and activity of lactate dehydrogenase (LDH) in the culture medium were detected.The apoptosis rate (AR) was calculated.Results Compared with group C,the viability of cardiomyocytes,AR and activity of LDH in the culture medium were significantly increased in group H/R (P ＜ 0.05).Compared with group H/R,the viability of cardiomyocytes,AR and activity of LDH in the culture medium were significantly decreased in HPC,RPC and BNI + RPC groups (P ＜ 0.05),and no significant changes were found in the parameters mentioned above in NTD + RPC,W + RPC,PD + RPC,NTD,BNI,W,and PD groups (P ＞ 0.05).The viability of cardiomyocytes was significantly lower,and the AR and activity of LDH in the culture medium were higher in NTD + RPC,BNI + RPC,W + RPC,and PD + RPC groups than in RPC group (P ＜ 0.05).Conclusion Remifentanil preconditioning activates PI3K/Akt and ERK signaling pathways possibly through activating δ opioid receptors thus attenuating H/R-induced injury to cardiomyocytes in rats.

Aim To screen the differentially expressed microRNAs ( miRNAs ) induced by hypoxia precondi-tioning ( HPC ) in adult rat cardiomyocytes, and pre-dict miRNAs-regulated target genes and their func-tions. Methods Cardiomyocytes were isolated from a-dult rat ventricular myocardium and cultured ( in vitro) . The cells were divided into 2 groups: control group ( CON ) and hypoxia preconditioning group ( HPC) . The cardiomyocytes in HPC group were sub-jected to 10 min hypoxia followed by 30 min reoxygen-ation, while the cells in CON group were cultured un-der normal condition. After that, total RNA was ex-tracted and then subjected to miRNA microarray to screen differentially expressed miRNAs. The microar-ray results were further validated by quantitative RT-PCR ( qRT-PCR ) . Bioinformatics analysis was per-formed to predict the miRNAs-regulated target genes and analyze the enriched gene ontology ( GO) and sig-naling pathway ( Pathway) . Results HPC caused sig-nificant changes in miRNAs expression in cardiomyo-cytes as compared to CON group. A total of 12 miR-NAs were up-regulated and 14 miRNAs were down-reg-ulated ( P <0. 01 , FDR <0 . 05 ) . The differentially expressed 7 miRNAs with a fluorescent signal intensity>500 were selected for further bioinformatics analysis. The expression of miR-133b-5p, miR-664-1-5p and miR-6216 detected by qRT-PCR exhibited the similar patterns of up or down regulation to those shown in mi-croarray results. Bioinformatics analysis revealed that miRNAs-regulated target genes were significantly en-riched in 27 GOs and 6 signal pathways. Conclusion
The expression profile of miRNAs in rat cardiomyo-cytes is significantly affected by HPC. These differenti-ally expressed miRNAs might participate in HPC-in-duced cardioprotection by regulating their target genes in rat cardiomyocytes.

Objective To evaluate the role of microRNA-133b-Sp (miR-133b-Sp) in apoptosis hypoxia/reoxygenation (H/R) induced by in rat cardiomyocytes.Methods Rat myocardial cell line H9c2 was cultured in DMEM/F12 culture medium supplemented with 10％ fetal bovine serum.The cells were seeded in 96-well or 6-well plates and randomly divided into 4 groups (n=64 wells each):control group (group C);group H/R;miR-133b-5p mimic + H/R group (group M+H/R);miR-133b-Sp negative control + H/R group (group NC+H/R).The cells were exposed to 95％ N2-5％ CO2for 5 h at 37 ℃ followed by 1 h reoxygenation in DMEM/F12 culture medium supplemented with 10％ fetal bovine serum in all the groups except group C.The cells were cultured in normal culture atmosphere in group C.In M+H/R and NC+H/R groups,the cells were transfected with miR-133b-5p mimic (final concentration 30 nmol/L) and miR-133b-5p negative control (final concentration 30 nmol/L),respectively,for 24 h before H/R.Total RNA was extracted from cells to detect the expression of miR-133b-5p using quantitative real-time PCR.The cell viability (by CCK-8) and lactic dehydrogenase (LDH) activity in the culture medium were detected.Cell apoptosis was assessed by Annexin V/PI flow cytometry.Apoptotic rate was calculated.Result Compared with group C,the cell viability was significantly decreased,and the LDH activity and apoptotic rate were increased in H/R,M+H/R and NC+H/R groups,the expression of miR-133b-5p was down-regulated in H/R and NC+H/R groups,and the expression of miR-133b-Sp was up-regulated in group M+H/R.Compared with group H/R,the cell viability was significanttly increased,the LDH activity and apoptotic rate were decreased,and the expression of miR-133b-5p was up-regulated in group M+H/R,and no significant change was found in the parameters mentioned above in group NC+H/R.Conclusion H/R in rat cardiomyocytes can induce cell apoptosis possibility through down-regulating the expression of miR-133b-5p

Objective To evaluate the effect of morphine preconditioning on the expression of miR-133b-Sp and Fas in rat cardiomyocytes subjected to hypoxia/reoxygenation (H/R).Methods Cardiomyocytes were isolated from healthy adult male Sprague-Dawley rats by using Langendorff perfusion.The cells were seeded into 24-well plates or 60 mm diameter dishes and randomly divided into 3 groups (n =24 each) using a random number table:control group (group C),group H/R,and morphine preconditioning group (group MPC).The cells in group C were cultured in normal culture atmosphere.In H/R and MPC groups,the cells were exposed to 95％ N2-5％ CO2 for 90 min followed by 120 min reoxygenation.In group MPC,the cells were cultured for 10 min in serum-free DMEM liquid culture medium containing morphine 1 μmol/L,and then were cultured for 30 min in morphine-free DMEM liquid culture medium before hypoxia.At 120 min of reoxygenation,the cells in 24-well plates were selected to detect the cell viability (by MTT),lactate dehydrogenase (LDH) activity in the culture medium,and cell apoptosis (by Hoechst 33234 staining).Apoptosis rate was calculated.Total RNA and protein were extracted from the cells in 60 mm dishes to detect the expression of miR-133b-5p and Fas mRNA (by quantitative real-time PCR) and Fas protein (by Western blot).Results Compared with C group,the cell viability was significantly decreased,LDH activity and apoptosis rate were increased,the expression of miR-133b-Sp was down-regulated,and the expression of Fas mRNA and protein was up-regulated in H/R group.Compared with H/R group,the cell viability was significantly increased,LDH activity and apoptosis rate were decreased,the expression of miR-133b-5p was up-regulatcd,and the expression of Fas mRNA and protein was down-regulated in MPC group.Conclusion The mechanism by which morphine preconditioning reduces H/R injury to rat cardiomyocytesis related to up-regulation of the expression of miR-133b-Sp and down-regulation of the expression of Fas.

Objective To evaluate the roles of 1-phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated kinase (ERK) signaling pathways in reduction of ischemia-reperfusion (I/R) injury to the isolated hearts by morphine preconditioning in the rats with chronic heart failure.Methods Adult male Sprague-Dawley rats,weighing 200-230 g,in which doxorubicin 2.0 mg/kg was injected via the tail vein once a week for 6 weeks to induce chronic heart failure,were studied.At the end of 8th week,42 rats with chronic heart failure were randomly divided into 7 groups (n =6 each) using a random number table:sham operation group (group S),I/R group,morphine preconditioning group (group MP),PD98059 (ERK inhibitor) + morphine preconditioning group (group PD + MP),wortmannin (PI3K inhibitor) + morphine preconditioning group (group WT + MP),PD98059 group (group PD) and wortmannin group (group WT).The hearts were quickly excised and passively perfused in a Langendorff apparatus and subjected to 30 min of occlusion of the left coronary artery followed by 2 h of reperfusion to establish the model of I/R injury.In group S,the hearts were only sutured,but not ligated and were continuously perfused with K-H solution for 195 min.In group I/R,the hearts were perfused with K-H solution for 45 min before ischemia.In group MP,the hearts were perfused with K-H solution for 15 min,with K-H solution containing morphine 1 μmol/L for 5 min and then with K-H solution for 5 min (3 cycles in total) before ischemia.In PD + MP and WT + MP groups,the hearts were perfused with K-H solution containing PD98059 (10 μmol/L) and wortmannin (100 nmol/L),respectively,starting from 10 min before morphine preconditioning until 5 min of ischemia.In PD and WT groups,the hearts were perfused with K-H solution containing PD98059 (10 μmol/L) and wortmannin (100 nmol/L),respectively,starting from 40 min before ischemia until 5 rin of ischemia.At 15 min of equilibration (baseline) and 5 and 10 min of reperfusion,the coronary flow was collected to detect the activity of lactate dehydrogenase (LDH).Infarct size (IS) and area at risk (AAR) were measured at the end of reperfusion and IS/AAR ratio was calculated.Results Compared with group S,LDH activity was significantly increased at 5 and 10 min of reperfusion,IS and IS/AAR ratio were also increased (P ＜ 0.05),and no significant change was found in AAR in group I/R (P ＞ 0.05).Compared with group I/R,LDH activity was significantly decreased at 5 min of reperfusion,IS and IS/AAR ratio were also decreased (P ＜ 0.05),and no significant change was found in AAR in group MP,and no significant change was found in LDH activity,IS,AAR and IS/AAR ratio in WT and PD groups (P ＞ 0.05).Compared with group MP,LDH activity was significantly increased at 5 and 10 min of reperfusion (P ＜ 0.05),and IS and IS/AAR ratio were decreased in group PD + MP,and no significant change was found in LDH activity,IS,AAR and IS/AAR ratio in group WT + MP (P ＞ 0.05).Conclusion Activation of ERK signaling pathway is involved in reduction of I/R injury to isolated hearts by morphine preconditioning in rats with chronic heart failure,however,PI3K signaling pathway has no such effect.

Aim To investigate the roles of mitogen-ac-tivated protein kinases ( MAPK ) pathways in the pro-tective effects of remifentanil preconditioning against is-chemia/reperfusion injury of isolated heart in rats with heart failure. Methods Adult male SD rats were injected with adriamycin via tail vein for 6 weeks to induce heart failure. The rats were confirmed chronic heart failure through echocardiography and randomly divided into 9 groups(n=6)as follows: sham group, ischemia/reperfusion group ( IR) , remifentanil precon-ditioning group( RPC) , ERK inhibitor PD98059+RPC group ( RPD ) , p38 inhibitor SB203580 +RPC group ( RSB ) , JNK inhibitor SP600125 + RPC group ( RSP ) , and the inhibitor control groups ( PD , SB and SP) . All hearts were linked to the Langendorff ap-paratus. The coronary effluent was collected to detect the activity of lactate dehydrogenase ( LDH ) at base-line, 5 min and 10 min after reperfusion, respectively. Infarct size ( IS) and area at risk ( AAR) were deter-mined by 2, 3, 5-triphenyl-tetrazolium (TTC) staining at the end of reperfusion. Left ventricular developed pressure ( LVDP), ± dp/dtmax and heart rate ( HR) were recorded to evaluate cardiac function in each group. Results When compared with IR group, RPC significantly reduced IS / AAR and decreased the ac-tivity of LDH at 5 min and 10 min after reperfusion. However, SP600125 almost thoroughly abolished the protective effects of RPC, as evidenced by the in-creased value of IS / AAR and the high activity of LDH. In addition, PD98059 also partly blocked the effects of RPC, while SB203580 showed no influence on RPC. Meanwhile, the hemodynamic parameters such as LVDP, HR and ± dp/dtmax were not signifi-cantly different in any group except sham group. Con-clusion JNK and ERK pathways may play an impor-tant role in cardioprotective effects of remifentanil pre-conditioning against ischemia/reperfusion injury in rats with heart failure.

Objective To study the effects of exogenous melatonin on plasma corticosterone(CS)and adrenal glucocorticoid receptor(GR)mRNA in neonatal rats after hypoxic-ischemic brain damage(HIBD). Methods One hundred and forteen 7-day-old Sprague-Dawley rats were randomly divided into four groups:model group(K group),sham operation group(H group),melatonin-treated group(T group),and normal control group(S group). Blood was obtained in different time points after HIBD. Plasma CS levels were measured by radioimmunoassay(RIA). The expression of GR mRNA was detected by semi-quantitative reverse transcriptase polymerase chain reaction(RT-PCR). Results Plasma level of CS increased and the expression of GR mRNA decreased significantly after HIBD,however,these changes were markedly reversed by exogenous melatonin. Conclusions Plasma CS and adrenal gland GR were involved in the pathological process of HIBD. Exogenous melatonin could up-regulate the expression of GR by decreasing the level of endogenous CS,so it may alleviate the excess stress injury after HIBD.