Design, Simulation and Experimental Study of a Novel Radiofrequency Tissue Welding Electrode / 医用生物力学

Objective Aiming at improving biomechanical strength of the anastomotic stoma as well as reducing tissue thermal damage, a novel radiofrequency (RF) tissue welding electrode was developed. Methods A novel electrode with a hollow structure on the surface ( the plum electrode) was designed and the ring electrode was used as control group to conduct the welding of intestinal tissues based on RF energy. Biomechanical properties of anastomotic stoma were studied by shear test and burst pressure test. The tissue thermal damage during welding was investigated by finite element electro-thermal-mechanical multi-field coupling simulation analysis and thermocouple probe, and the tissue microstructures were also studied. Results Under 120 W RF energy, 8 s welding duration and 20 kPa compression pressure, the anastomotic stoma had the optimal biomechanical properties. Compared with the ring electrode group, biomechanical strength of the anastomotic stoma in plum electrode group was higher, with the shear strength and burst pressure increasing from (9. 7±1. 47) N, (84. 0±5. 99) mmHg to (11. 1±1. 71) N, (89. 4±6. 60) mmHg, respectively. There was a significant reduction in tissue thermal damage, and intact and fully fused stomas could be formed in anastomotic area. Conclusions The proposed novel electrode could improve biomechanical strength of the anastomosis as well as reduce tissue hermal damage, thus achieve better fusion. The research result provide references for realizing the seamless connection of human lumen tissues

Effect of morphine preconditioning on expression of miR-133b-5p and Fas in rat cardiomyocytes subjected to hypoxia/reoxygenation / 中华麻醉学杂志

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.

Role of microRNA-133b-5p in apoptosis induced by hypoxia/reoxygenation in rat cardiomyocytes / 中华麻醉学杂志

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

Effects of morphine preconditioning on expression of microRNAs during hypoxia-reoxygenation in H9 c2 myocardial cells / 中国药理学通报

Aim To evaluate the effects of morphine preconditioning ( MPC ) on the expression of microR-NAs ( miRNAs ) induced by hypoxia-reoxygenation (H/R) in H9c2 myocardial cells. Methods H9c2 cells were randomly divided into 3 groups ( n=4 each) as follows:control group ( CON) , hypoxia/ reoxygen-ation group ( H/R ) and morphine preconditioning group ( MPC+H/R) . The cells were cultured in nor-mal condition in CON group. The cells were subjected to 5 h hypoxia followed by 1 h reoxygenation in H/R group and MPC+H/R group. Specifically, the cells in MPC+H/R group were preconditioned with morphine with the final concentration of 1 μmol·L-1 for 10 min before H/R. After the treatment, CCK-8 was used to detect cell viability and chemical colorimetry was used to detect lactate dehydrogenase ( LDH ) activity in the culture medium. Cell apoptosis was assessed by An-nexin-V-FITC/PI flow cytometry. Relative expression of Fas protein was detected by Western blot. The ex-pression of miRNA in myocardial cells was analyzed by quantitative reverse transcription polymerase chain re-action ( qRT-PCR ) . Results Compared with CON group, the cell viability was significantly decreased, while the LDH activity, apoptotic rate and Fas protein expression were dramatically increased in group H/R (P<0. 01). However, MPC significantly increased the cell viability, whereas it decreased the LDH activity, apoptotic rate and Fas protein expression induced by H/R injury ( P < 0. 01 ) . The expressions of miR-133a-5p, miR-133b-5p, miR-664-1-5p, miR-6216 and let-7 e-5 p were markedly down-regulated by H/R as compared to CON group ( P <0. 05 ) , while MPC inhibited these miRNAs which were significantly down-regulated by H/R group ( P <0. 01 ) . Conclusion Morphine preconditioning might protect H9 c2 myocar-dial cells against H/R injury by regulating the expres-sion of miRNAs such as miR-133a-5p, miR-133b-5p, miR-664-1-5p, miR-6216 and let-7e-5p.