| In the present study, PC 12 cells were used as dopaminergic neuron cells with high glucose (HG) and methylglyoxal (MG) in cell culture medium to establish a typical cell model of diabetic encephalopathy in vitro, aimed to investigate the protective effect of catalpol as a potential preventive or therapeutic drug for diabetic encephalopathy.HG and MG are very common in human tissues and are known to play pivotal roles in diabetes complications. In PC 12 cell cultures, HG and MG were added to cell medium to cause PC 12 cell damage and different cytotoxic effect of the two drugs were investigated and compared to establish an efficient and steady cell model of diabetic encephalopathy in vitro. MTT assay was used to determine the cell viability, results showed that after 1mM MG treated PC12 cells 48h, the cell viability was 58.13%±2.66% and slight alteration of cell viability happened after HG treated PC 12 48 h. Likewise, analysis on lactate dehydrogenase (LDH) leaking demonstrated that LDH release level grew to 57.26±2.13% after 1mM MG treated PC12 cells 48h. Hoechst 33258 staining and fluorescence micro-plate reader of Rh123 were performed to detect cell morphology and cell karyopyknosis and results demonstrated that MG caused obvious cell morphologic changes compared to HG treated PC 12 cells. The above results demonstrated that MG was more effective to induce PC 12 cell damage and could be served as cytotoxic factor to establish cell model of diabetic encephalopathy.Catalpol was extracted from rehmannia with the ability of glucose lowering and antioxidation. In this study, the protective effect of catalpol on the MG-induced PC 12 cells damage was explored. The cell viability assay and LDH release level analysis revealed that catalpol could improve viability of MG-treated PC12 to 70.1±2.98% and lower the LDH leakage level to 48.92±3.86% by keeping the integrity of PC12 cell membrane; the loss of mitochondria membrane potential (MMP) grew to 67.5±2.51% with 0.1mM catalpol pretreated PC 12 cells prior to MG treated. Study results suggested that catalpol could prevent the MG-induced damage by preventing reduing loss of MMP, activate the antioxidation system of PC 12 cells, and up-regulate Bcl-2 protein expression level or down-regulate Bax protein expression level to alter the ratio of Bcl-2/Bax protein.In conclusion, the above results indicated that MG possessed potent cytotoxicity to cause PC 12 cells damage effectively and could serve as cytotoxic factor to establish an efficient and steady cell model of diabetic encephalopathy; pretreatment of catalpol prevented MG-induced PC12 cell damage and could be served as a potential prevention or therapeutic drug for diabetic encephalopathy. |
