| AIM DM had become the third most harmful disease in the world. Recently, a series of animal experiments and clinical trials suggested that oxidative damage may be one of the common mechanisms of DM and it's complications, while researchers sill thought little of this and systematic data on oxidative mechanism were also destitute. Besides, as an important approach of DM researches, animal models induced by STZ were widely used. But recently several experiments oppugned the specific damage to pancreas ialet of STZ. Therefore, in this study, several tests were designed to profoundly probe ROS evoking factors, generating sites, character and phases of action, processes and tyes of damage, further understand cognizing oxidative damage mechanism of DM and test whether STZ could damage tissues excluding pancreas islet.Methods Protein glycation sytem was built in water medium in vitro to investigate the influence of different intervention on protein glycation. Microsome in liver cell were extracted and three microsomal LPO models were built to investigate influences of different interventions on LPO in the subcellular level. Liver cells were primarily separated and cultured from SD rats to investigate influences of different interventions on oxidative and/or antioxidant parameters and insulin receptor in liver cells. DM rats induced by STZ were produced and meanwhile blood glucose was controlled by insulin to investigate whether STZ could caused damages in tissues excluding pancreas islet in animal level. Results Protein glycation tests showed that non-enzymatic protein glycationwere significantly affected by H2O2, CHP and VitC/Fe2+ in time-dependent and dose-dependent ways. Identification of AGEs prepared in vitro by fluorescence spectrum scanning showed the peak was at EM440-450nm, which was coincident with the fluorescence character. AGEs content was significantly decreased after protein glycation system were incubated with GSH and LA for 8 weeks. The preventive effects of GSH was more potent than LA, but they both showed no significant influence on carbonyl content in protein glycation system. Incubation of Ins and D-Glu for 8 weeks showed AGEs content was significantly increased. Hepatic microsomal tests showed MDA content was significantly increased with STZ concentration increasing in three LPO models. D-Glu dissolved in serum showed similar effects, but its aqueous solution showed no such influence. AGEs also showed a similar influence on LPO in microsomal models under a higer concentration. Cell tests showed primary separated liver cells were dispersive, transparent and tridimensional. Trypan blue staining showed their survival rate was more than 80%. Bmax1 and Kd1 of IR with higher binding capability were significantly increased after incubation of liver cell with H2O2 under hither final concentration(80 160umolL-l), and Kd2 of IR with lower binding capability was significantly decreased under 40umol L-1 of H2O2. T-SOD activity was significantly decreased and MDA content was significantly increased after incubation of liver cell with D-Glu under 25 and 50mmol L-1. T-SOD and Mn-SOD activity were significantly decreased and MDA content was significantly increased after liver cell was incubated with different concentration of AGEs. T-SOD and Mn-SOD activity showed no significant changes after incubation of liver cell with defferent doses of STZ for 4h, but MDA content was significantly increased under higher final concentration 1.5 and 1.8mg mL-1). Wistar rats injected with high dose of STZ showed polydipsia, polyuria, polyphagia, depilation and weight descending, and their blood glucose showed a 3-phase changes. While these changes were not significant in rats with low dose of STZ injection. The MDA, SOD, GSH, GSSH in serum, kidney, liver and lung showed no significant difference between rats injected with STZ+insulin and normal rats. Conclusions (1) Protein glycation could be facilitated by ROS and ROS generating agents in vitro by time-dependent and dose-dependent way. (2) We were successful in preparing AGEs i...
|
PDF Full Text Request