Mesenchymal stem cells-conditioned medium protects PC12 cells against 2,5-hexanedione-induced apoptosis via inhibiting mitochondria-dependent caspase 3 pathway.

Studies suggested that the conditioned medium of mesenchymal stem cells (MSC-CM) inhibited the increased apoptosis in various cells. However, there are no reports underlying the protection of MSC-CM against 2,5-hexanedione (HD)-induced apoptosis in neural cells. In the present study, the viability was observed in PC12 cells that received HD alone or with MSC-CM by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Apoptosis was estimated by Hoechst 33342 staining and flow cytometry. Mitochondrial transmembrane potential was examined by rhodamine 123. Moreover, we investigated the expression of Bax and Bcl-2, cytochrome c translocation, and caspase 3 activity by real-time polymerase chain reaction, Western blot, and immunochemistry. Nerve growth factor (NGF) was examined in MSCs and MSC-CM. Our results showed that MSC-CM promoted cell survival and reduced apoptosis in HD-exposed PC12 cells. Moreover, MSC-CM significantly reversed disturbance of Bax and Bcl-2, ameliorated disruption of mitochondrial transmembrane potential, and reduced release of cytochrome c and activity of caspase 3 in HD-exposed PC12 cells. In the meantime, NGF was detected in MSCs and MSC-CM. These findings demonstrate that MSC-CM protects against HD-induced apoptosis in PC12 cells via inhibiting mitochondrial pathway. Our results indicate that NGF in MSC-CM may be involved in the protection of MSC-CM against HD-induced apoptosis. Our study clarifies the protection of MSC-CM on HD neurotoxicity and its underlying mechanism.

[Diagnostic value of double contrast-enhanced ultrasonography in preoperative staging of gastric cancer].

OBJECTIVE: To evaluate the clinical value of double contrast-enhanced ultrasonography using oral and intravenous contrast agents in preoperative staging of gastric cancer. METHODS: Sixty-two patients with biopsy-proven gastric cancer were enrolled into this study, and were examined by double contrast-enhanced gastric ultrasonography preoperatively. The results were compared with postoperative pathologic findings. RESULTS: The accuracy of oral contrast-enhanced gastric ultrasonography and double contrast-enhanced ultrasonography in determining the T stage of gastric cancer was 72.9% (T1: 66.7%, T2: 60.0%, T3: 76.9%, T4: 71.4%) and 88.1% (T1: 66.7%, T2: 80.0%, T3: 89.7%, T4: 100%), respectively, with a statistically significant difference between the two methods (P = 0.036). The sensitivity, specificity, accuracy and Youden index of oral contrast-enhanced gastric ultrasonography and double contrast-enhanced ultrasonography in assessment of lymph node metastasis were 74.5%, 66.7%, 72.9%, and 0.41 versus 89.4%, 75.0%, 86.4%, 0.76, respectively. No significant difference in the accuracy of assessment for lymph node metastasis was observed (P > 0.05). CONCLUSION: Double contrast-enhanced ultrasonography is useful for preoperative staging of gastric cancer, especially for T staging.