AIM:To investigate the role of Epac/Rap1 signaling pathway in hypoxia-reoxygenation injury in H9c2 cells,and to explore the mechanism of vitexin regulating the Epac/Rap1 signaling path-way to protect cardiomyocytes from hypoxia-reoxy-genation injury.METHODS:The oxygen glucose de-privation(OGD)model was established using H9c2 cardiomyocytes to simulate hypoxia-reoxygenation injury.The experiment was randomly divided into 7 groups:Normal control group,OGD group,OGD+VT group,OGD+8-CPT+VT group,OGD+ESI-09+VT group,OGD+8-CPT+VT+H-89 group,OGD+ESI-09+VT+H-89 group.Cell viability was measured by MTT.LDH was used to detect cell damage.The ex-pression levels of Epac1 and its downstream Rap1-GTP,CaMK Ⅱ and ERK proteins in H9c2 cells were detected by Western blot.The expression of Epac1 and Rap1 proteins in H9c2 cardiomyocytes was de-tected by immunofluorescence.The mRNA expres-sion of Rap1 and Epac1 in H9c2 cardiomyocytes was quantitatively determined by real-time PCR.Calcium ion fluorescence probe(Fluo-3 AM)was used to detect intracellular[Ca2+]i content.The in-teraction between Epac1 and Rap1 in cells were de-tected by Co-IP.RESULTS:Compared with the nor-mal control group,after hypoxia for 5 h and reoxy-genation for 1 h,the release of LDH,cell viability,Epac1 protein expression,Rap1 activation and RAP1-GTP up-regulation of H9c2 cardiomyocytes in OGD group were significantly increased.VT(10μmol/L)significantly inhibited the activation of Epac1 in H9c2 cardiomyocytes after OGD,and then inhibited the expression of downstream Rap1 ac-tive form Rap1-GTP.In addition,the expression of CaMK Ⅱ protein was down-regulated,but ERK phosphorylation was increased,and intracellular calcium overload was alleviated.Epac1 agonist 8-CPT could counteract the effect of VT,and Epac1 in-hibitor(ESI-09)combined with VT had synergistic effect.PKA inhibitor(Hmur89)had no effect on the expression of Epac1 and its downstream related proteins in cardiomyocytes.CONCLUSION:Hypoxia-reoxygenation can mediate the activation of Epac1/Rap1 signal pathway in cardiomyocytes.VT can pro-tect cardiomyocytes from hypoxia-reoxygenation in-jury by inhibiting Epac1/Rap1 signal pathway,down-regulating CaMK Ⅱ protein expression and promoting ERK phosphorylation.

Objective: To evaluate the efficacy of transversus abdominis plane block (TAPB) with different doses of dexmedetomidine mixed with ropivacaine in the pediatric patients undergoing laparoscopic surgery with general anesthesia. Methods: Eighty patients of both sexes, aged 3-6 yr, weighing 10-30 kg, scheduled for elective single-channel laparoscopic appendectomy, were divided into 4 groups (n=20 each) using a random number table method: 0.5 μg/kg dexmedetomidine plus ropivacaine group (group DR₁), 1.0 μg/kg dexmedetomidine plus ropivacaine group (group DR₂), 1.5 μg/kg dexmedetomidine plus ropivacaine group (group DR₃), and ropivacaine group (R group). Bilateral TAPB was performed under ultrasound guidance after the end of anesthesia induction.In group TR, 0.25% ropivacaine 0.5 ml/kg was injected, the 0.5 ml/kg mixture of 0.5, 1.0 and 1.5 μg/kg dexmedetomidine and ropivacaine at a final concentration of 0.25% was injected in DR₁, DR₂ and DR₃ groups.Anesthesia was maintained by intravenously infusing remifentanil and inhaling sevoflurane.Cisatracurium was intermittently injected to maintain muscle relaxation.Ibuprofen was taken orally to maintain postoperative FLACC score <4.The intraoperative consumption of remifentanil, tracheal extubation time, duration of anesthetic recovery room stay, requirement for ibuprofen, and occurrence of opioids- and TAPB-related complications were recorded. Results: There was no significant difference in the intraoperative consumption of remifentanil or tracheal extubation time between four groups (P>0.05). Compared with group R, the requirement for ibuprofen was significantly decreased in DR₂ and DR₃ groups, the duration of anesthetic recovery room stay was significantly prolonged in group DR₃ (P<0.05), and no significant change was found in the requirement for ibuprofen in group DR₁ or in the duration of anesthetic recovery room stay in DR₁ and DR₂ groups (P>0.05). Compared with group DR₁, the duration of anesthetic recovery room stay was significantly prolonged, and the requirement for ibuprofen was decreased in group DR₃, and the requirement for ibuprofen was significantly decreased (P<0.05), and no significant change was found in the duration of anesthetic recovery room stay in group DR₂ (P>0.05). Compared with group DR₂, the duration of anesthetic recovery room stay was significantly prolonged (P<0.05), and no significant change was found in the other parameters in group DR₃ (P>0.05). No patients developed opioids- or TAPB-related complications. Conclusion TAPB with 1.0 μg/kg dexmedetomidine mixed with ropivacaine provides good efficacy for the pediatric patients undergoing laparoscopic surgery with general anesthesia.