AIM: To explore the role of extracellular signal-regulated kinases ERK1/2-STAT3 pathway in adaptive cytoprotection induced by H2O2 preconditioning in PC12 cells.METHODS: In PC12 cells,the experimental model of cytoprotection by H2O2 preconditioning against oxidative stress-induced injury was set up.The morphological changes in the apoptotic cells were observed by using of chromatin dye Hoechst 33258.The percent of apoptotic cells was determined by flow cytometry(FCM) with propidium iodide staining.The levels of p-ERK1/2 and p-STAT3 expression were detected by Western blotting assay.RESULTS: Preconditioning with H2O2 at concentration of 100 ?mol/L for 90 min obviously inhibited apoptosis induced by 300 ?mol/L H2O2,and both ERK1/2 and STAT3 were activated.UO126(10 ?mol/L,an inhibitor of ERK1/2) or AG-490(10?mol/L,an inhibitor of JAK2) significantly blocked the cytoprotection effect of H2O2 preconditioning.Moreover,UO126(10 ?mol/L) also markedly inhibited the up-regulation of p-STAT3 expression by H2O2 preconditioning.CONCLUSION: H2O2 preconditioning activates ERK1/2-STAT3 signal pathway,which may be one of the mechanisms underlying H2O2 preconditioning-induced cytoprotection.

AIM: To explore the roles of heat shock protein 90 (HSP90) in the blockage of hydrogen sulfide (H2S) against chemical hypoxia-mimetic agent (cobalt chloride, CoCl_2)-induced oxidative stress injuries in H9c2 cardiac cell. METHODS: H9c2 cells were treated with CoCl_2 to set up the chemical hypoxia-induced the model of cardiomyocyte injury. Sodium hydrosulfide (NaHS, a H2S donor) was added into medium for 30 min before CoCl_2 treatment. ATP content was detected by high performance liquid chromatogram (HPLC). Mitochondrial membrane potential (MMP) was measured by rhodamine123 (Rh123) staining and photofluorography. The activity of superoxide dismutase (SOD) was observed using a SOD kit. The expression of heme oxygenase-1 (HO-1) was evaluated by Western blotting. RESULTS: CoCl_2 at concentration of 600 μmol/L significantly reduced SOD activity, ATP level and MMP, and enhanced the expression of HO-1 in H9c2 cells. Pretreatment with 400 μmol/L NaHS dramatically inhibited the cytotoxicity induced by CoCl_2, increased SOD activity, ATP level and MMP, decreased HO-1 expression. 17-allylamino-17 demethoxygeldanamycine(17AAG), an inhibitor of HSP90, obviously blocked the inhibitory effect of H2S on the CoCl_2-induced cytotoxicity, reduced the levels of ATP and MMP, increased HO-1 expression. However, no significantly influence on SOD activity was observed. CONCLUSION: HSP90 may mediate the cardioprotection of H2S via inhibiting the oxidative stress induced by chemical hypoxia.

Objective To use the deep learning methods to extract features of the 1st to 7th adult costal cartilage CT reconstruction images to realize the automatic estimation of adult costal cartilage bone age.Methods 625 male and 625 female samples aged between 20 and 70 years old were collected retrospectively,and the corresponding VRT images were reconstructed by volume rendering technology(VRT).After image preprocessing and data augmentation,500 cases were used as the training set and 125 cases as the test set.The performance of ResNet,ResNeXt,DenseNet and GoogleNet networks was evaluated by using 5-fold cross-validation,and the average value of 5-fold cross-validation results was taken as the final estimation result.Results The ResNet50 network achieved the best results in both male and female datasets.The mean absolute error was 4.56 years and 3.91 years,the accuracy rate was 64.00%and 70.88%in the range of±5.0 years,88.96%and 94.40%in the range of±10.0 years,respectively.Conclusion Compared with traditional methods and machine learning methods,the deep learning models can avoid the influence of human factors,greatly improve the accuracy of adult costal cartilage bone age estimation,and reduce the error between predicted age and real age,which has high clinical application value.