Objective:To establish the myocardial ischemia-reperfusion injury (MIRI) model by ligation of the left ventricular branch of coronary artery in rabbits.Methods:Totally 36 New Zealand white rabbits were randomly divided into 3 groups according to the random number table method, including the sham group ( n=6), the model group ( n=15), and the sustained ischemia group ( n=15). The rabbits were placed under general anesthesia, then endotracheal intubation and common carotid artery intubation were performed. The intercostal muscle between the 3rd and 4th ribs of the left thorax was divided with the aid of a ventilator. The left ventricular branch was located and processed according to the different groups. After successful modeling, the gross morphological change of the heart was observed by naked eye, and the survival rate and modeling success rate of rabbits in each group were calculated respectively. Record the waveform of limb lead Ⅱ electrocardiogram before left ventricular branch ligation (N), 45 minutes of ischemia (I45), 15 minutes of reperfusion (R15), 30 minutes of reperfusion (R30), and 60 minutes of reperfusion (R60). Serum cardiac troponin Ⅰ (cTnⅠ) level was detected by enzyme-linked immunosorbent assay (ELISA), myocardial infarct size ratio was detected by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining, and the change of myocardial tissue changes were detected by hematoxylin-eosin (HE) staining. Results:The survival rate of the rabbits was 93.33% (14/15) in the model group, and the success rate of MIRI modeling was 86.67% (13/15). In the model group, the ST segment (5.00±0.71) mm at I45 was higher than that before the ligation (1.20±0.27) mm, the difference was statistically significant ( P<0.01), and it was stable throughout the whole ischemia period. After ligation removal, the ST segment decreased to (3.00±0.61) mm at R15, (2.20±0.45) mm at R30, and (1.30±0.27) mm at R60. There were statistically significant differences between I45 and N, R15 and I45, and R60 and R15 (all P<0.01). The pathological Q-wave was (1.60±0.55) mm at R15, and decreased to (3.60±0.22 and 5.10±0.22) mm at R30 and R60, respectively. There were statistically significant differences between R30 and R15, R60 and R30, and R60 and R15 (all P<0.01). ST segment (6.10±0.42, 5.80±0.45, 5.60±0.22, and 5.30±0.27) mm at I45, I60, I75 and I105 respectively were higher than the ST segment (1.10±0.22) mm at N in the sustained ischemia group, and the differences were statistically significant (all P<0.01). The serum cTnⅠlevels in the model group at N, I45, R30 and R60 were (62.74±1.60, 97.60±6.36, 159.30±17.64, and 166.40±18.56) ng/L, respectively, and the difference between I45 and N was statistically significant ( P<0.05). There were statistically significant differences between R30 and I45, R60 and I45, and R30 and N (all P<0.01). The serum cTnⅠlevels in the sustained ischemia group were (69.00±4.85, 107.90±7.12, 140.60±10.96, 171.00±15.40) ng/L at N, I45, I75 and I105, respectively. There were statistically significant differences between I45 and N, I75 and I45, and I105 and I75 (all P<0.01). The infarct size ratios of the model group and the sustained ischemia group were 39.93% and (52.16±0.06) %, respectively, and the difference was statistically significant ( P<0.05). Conclusions:The method of establishing a MIRI model by ligating the left ventricular branch of the coronary artery in rabbits is simple to operate, with stable and reliable, and the success rate of modeling is high.

OBJECTIVE: To assess the value of using flat-sided culture tubes for preparing chromosomes through chorionic villi (CV) and amniotic fluid (AF) cell cultures during prenatal diagnosis. METHODS: From February to March 2020, 157 CV samples and 147 AF samples subjected to prenatal diagnosis at the Maternal and Child Health Care Hospital of Guangxi Zhuang Autonomous Region were selected as the study subjects. For each sample, one flat-sided tube and one flask culture were set up by following the standard protocols. The methods were evaluated by comparing the cell growth, experimental process, quality of chromosome preparation and costs. RESULTS: The success rates for the culturing of CV and AF samples by the flat-sided culture tube method were 97.45% (153/157) and 97.96% (144/147), respectively. By contrast, the success rates for the conventional flask method were 98.72% (155/157) for CV and 98.64% (145/147) for AF samples. No significant difference was found between the two methods (P > 0.05). The average harvest time required by the flat-sided culture tube method was 8.45 days for CV and 9.43 days for AF cultures, whilst the average harvest time for conventional flask method was 9.05 days and 9.54 days, respectively. The flat-sided culture tube method for CV had required significantly shorter average harvest time than the conventional method (P < 0.001). No statistical significant difference was found in the average harvest time for AF by the two methods (P > 0.05). The conventional culturing method had required three containers with two sample transfers. By contrast, the flat-sided culture tube method was carried out in one tube without any sample transfer. The average total amount of medium used was 3.91 mL for each flat-sided culture tube and 6.26 mL for each conventional flask. CONCLUSION The flat-sided culture tube method can provide a simple, cost-effective and error-reducing procedure for the CV and AF samples culture during prenatal diagnosis.
Child ; Female ; Pregnancy ; Humans ; China ; Prenatal Diagnosis ; Chorionic Villi Sampling ; Amniotic Fluid ; Cell Proliferation