OBJECTIVETo study the effect of arsenic on neuronal cell apoptosis and the mRNA and protein expression of calpain 1, calpain 2, and cyclin-dependent kinases 5 (cdk5)/p25 and to provide a scientific basis for the research on neurotoxic mechanism of arsenic trioxide (As2O3).

METHODSPrimary cultured rat neurons were divided into untreated control group, dimethyl sulfoxide (DMSO) solvent control group, and 1, 5, and 10 µmol/L As2O3 treated groups. Eight hours after being treated with As2O3, cell apoptosis rate was determined by flow cytometry, the mRNA expression of calpain 1, calpain 2, cdk5, and p35 was measured by real-time fluorescence quantitative PCR, and the protein expression of calpain 1, calpain 2, cdk5, p35, and p25 was measured by Western blot.

RESULTSCompared with those in the untreated control group and DMSO solvent control group, the cell apoptosis rates in the 5 and 10 µmol/L As2O3 treated groups were significantly increased (P < 0.05). The mRNA expression levels of calpain 1 were 6.36±3.26, 7.11±5.13, and 7.47±2.59 in the 1, 5, and 10 µmol/L As2O3 treated groups, respectively, and the mRNA expression levels of cdk5 were 1.27±0.19, 1.54±0.04, and 1.79±0.21 in the 1, 5, and 10 µmol/L As2O3 treated groups, respectively, which were significantly higher than those in the untreated group (0.72±0.15 and 1.77±0.87) and those in the DMSO solvent control group (0.96±1.23 and 1.18±0.09) (P < 0.05). The mRNA expression levels of p35 in the 1 and 5 µmol/L As2O3 treated groups were 2.17±0.59 and 2.51±0.51, respectively, which were significantly higher than that in the untreated control group (1.26±0.37) (P < 0.05). The protein expression levels of calpain 1 were 0.37±0.10, 0.42±0.13, and 0.51±0.18 in the 1, 5, and 10 µmol/L As2O3 treated groups, respectively, which were significantly higher than those in the untreated control group (0.11±0.08) and DMSO solvent control group (0.13±0.07) (P < 0.05). In the 5 and 10 µmol/L As2O3 treated groups, the protein expression levels of cdk5 were 0.34±0.12 and 0.37±0.21, while the protein expression levels of p25 were 0.31±0.23 and 0.55±0.16, all of which were significantly higher than those in the untreated control group and DMSO solvent control group (P < 0.05). The protein expression levels of p35 were reduced in the 5 µmol/L As2O3 treated group (0.31±0.23) and 10 µmol/L As2O3 treated group (0.26±0.16), as compared with those in the untreated control group and DMSO solvent control group (P < 0.05). The mRNA and protein expression of calpain 2 showed no significant differences between all groups (P > 0.05).

CONCLUSIONThe calpain 1-cdk5/p25 pathway may be involved in the process of As2O3-induced neuronal cell apoptosis.

Animals ; Apoptosis ; drug effects ; Arsenic Poisoning ; Arsenicals ; Calpain ; metabolism ; Cells, Cultured ; Cyclin-Dependent Kinase 5 ; metabolism ; Neurons ; drug effects ; metabolism ; Oxides ; toxicity ; Rats

Objective:To explore the role and safety of endomyocardial biopsy (EMB) in the diagnosis of pediatric myocardial disease.Methods:Demographic, clinical and histopathological data of all children receiving EMB in Shanghai Children′s Medical Center, Shanghai Jiaotong University School of Medicine between January 2016 and August 2020 were collected.The pathological results and the procedure-related complications were retrospectively analyzed.Results:A total of 22 patients with the mean age of (10.2±3.1) years underwent EMB.Among them, 13 cases (59.1%) underwent right ventricular EMB, 5 cases (22.7%) underwent left ventricular EMB, and 4 cases (18.2%) underwent biventricular EMB.Among the 12 patients with clinically suspected myocarditis or unexplained heart failure, 4 cases were diagnosed with lymphocytic myocarditis, 2 cases were dilated cardiomyopathy, and 1 case was inflammatory cardiomyopathy.Seven patients presented ventricular diastolic dysfunction, including 6 cases of restrictive cardiomyopathy and 1 of constrictive pericarditis.Three patients exhibited hypertrophic cardiomyopathy with pre-excitation syndrome, involving 2 cases were diagnosed with glycogen storage cardiomyopathy.EMB was successfully performed in all patients.No patient died, and procedure-related complications were not reported.Conclusions:EMB assists the diagnosis and treatment of pediatric patients with selected myocardial disease, which is relatively safe with less complications if performed by experienced interventionalists in qualified pediatric cardiovascular medical centers.