| Reality by the radiation environment in which the opportunity of people exposed to radiation is very large, from the food irradiation, medical-ray to ionizing radiation in space, radiation is everywhere. High-dose radiation can cause a variety of body tissue and organ damage, and even induced cell mutations, cancer, death and other serious consequences. Radiation produced a large number of free radicals, and thus resulting in oxidative stress is a major role in radiation damage to one of the mechanisms. Pyrroloquinoline quinone( PQQ) is a complementary base oxidoreductase as electron donor and recipient to participate in the process of oxidation and reduction.Many studies have shown that PQQ has a strong free radical scavenging capacity. Hari as such built PQQ bacteria genetically engineered to have a stronger free radical scavenging capacity, increase in catalase and superoxide dismutase dynamic, showing the strong radiation resistance. A preliminary study in our laboratory shows that PQQ-ray irradiation of high energy electron-induced skin damage in rats have some protective effect. In this study, to be anti-oxidative damage from the point of view, we research on the PQQ-ray irradiation cells 60Coγradiation effects; At the same time, establish 60Coγray irradiation injury model in mice to further investigate the radiation damage of PQQ protective effect of animals.I. the effects of antioxidant capacity by PQQ (pyrroloquinoline quinone) 60Coγ-ray irradiation on human gastric cancer cell line AGS cellsObjective: To detect the PQQ-ray irradiation of 60Coγthe growth of AGS cell proliferation, cell antioxidant levels and free radical content, for researching PQQ cells to radiation and its mechanism. Methods: AGS cells with 10% fetal bovine serum in the culture medium RPMI1640, put in 37℃, 5﹪CO2 incubator to maintain saturated humidity, ambient temperature of 25℃. Logarithmic phase cells, by trypan blue exclusion, living cells of which are more than 80% are used in the experiment. The experiment is divided into four groups: normal non-irradiated group, the simple irradiated group, PQQ handling non-irradiated group, PQQ handling irradiated group. Join in the PQQ 4h before exposure, with PQQ final concentration of 10μmol/L in it.Under room temperature conditions,the irradiated cells 60Coγ-ray irradiation, radiation dose 8Gy, dose rate 1Gy/min, one-time exposure. After irradiation in each group have MTT determination in 6h, 24h, 48h, 72h, render the cells after exposure to the growth curve; break down cells in each group irradiated 6h, 12h, 24h, to prepare cell homogenates for evaluation of cell T-AOC, SOD and MDA content.Results:①The normal AGS cell group's growth curve shows inverted "Z"-shape, 24h-48h cells in exponential growth; The others show that cell proliferation is restrained. MTTA570 via PQQ pretreatment of the irradiated group cells stay at a low level, with a rapid rise 48h later on.②6h, 12h, 24h after irradiation, T-AOC, SOD, MDA content compared with normal control group: in the simple irradiated group of cells, T-AOC and SOD was significantly decreased, MDA significantly increased; SOD, T-AOC content in the group of PQQ handling irradiated cells was significantly higher than the normal group and simple irradiated, although MDA content is more than the normal control group, yet significantly lower than the simple irradiated group.Conclusions:γ-ray irradiation caused a lower level of anti-oxidation, free radicals to increase.γ-ray irradiation on the PQQ of AGS cells have less damage. Its mechanism: on the one hand, PQQ directly scavenging free radicals, and modifying other activities of the department of antioxidant enzymes, in particular the activity of SOD to protect cells from free radical attack; on the other hand, through the delayed cell proliferation after irradiated, it is conducive to genetic material to repair the damage.II. The preliminary study on the role of PQQ (pyrroloquinoline quinone) on theγ-ray radiation protection in mice Objective: To establish a mouse model of 60Coγ-injury, oral gavage of PQQ, detection of serum levels of anti-oxidation and liver tissue damage, for a preliminary study of theγradiation PQQ protective effect in mice.Methods: 8-week-old Kunming mice, half male and female. 1 week after feeding adaptation. Mice were randomly divided into non-irradiated group and irradiated group, in which components are low-dose irradiation group(5Gy) and the high-dose irradiation group(10Gy). the radiation dose components can further be classified into: the oral group of PQQ before irradiation, the oral group of PQQ after irradiation, the simple irradiation group, 10 in each group. Oral administration in mice fed with PQQ, the oral dose 2mg/kg/d according to the weight. Mice of the oral group of PQQ before irradiation be administrated for 7 days, for the next day, the packet 60Coγ-ray single irradiation is required. Mice of oral group PQQ after irradiation take administration of 7 days from the current day. On the 8th day after irradiation, all mice were killed by cervical dislocation. Then prepare serum and liver homogenate, -20℃to preserve, for the determination of the indicators. At the same time, prepare liver biopsy, HE staining to observe the structural changes.Results: All 10Gy irradiated mice died eight days after irradiation; The oral group of PQQ before irradiation have the mean survival 7 days, the average survival of oral PQQ after irradiation is 6.2 days, a simple irradiation group survived an average of 5.3 days. As to 5Gy simple irradiated mice, the serum and liver antioxidant levels significantly decreased and the content of MDA significantly increased; liver plate shows a little disorder, marked edema of the phenomenon of liver cells. And as for oral PQQ groups of mice, serum SOD, T-AOC were significantly increased. Although the content of MDA is higher than normal control group, yet significantly lower than the irradiation alone group; liver content of SOD increased significantly. From HE staining of mice liver tissue slices: All irradiated mice shows liver tissue plate with both liver disorders, perisinusoidal space narrowing or disappearing, liver cells localized edema, degeneration and necrosis, oral PQQ groups before and after irradiation shows a little more liver radiation damage than the simple irradiaion group.Conclusions:γ-ray irradiation in mice caused systemic oxidative stress, liver is one of the radiation-sensitive organs. The study shows: PQQ forγ-ray irradiation-induced oxidative stress in mice has some protective effect. PQQ could be used to extend, to some extent, the survival time of irradiated mice. Its mechanism: PQQ can directly scavenge free radicals, at the same time, mobilize the whole body irradiated mice scavenging system, particularly the activity of SOD and reduce the generation of free radicals. In addition, probably because of a short time for the mice to take PQQ and long-term dose of medication and so on, PQQ did not show up on radiological protection to the liver. Further it shows that the PQQ concentration, handling mode and action time determine its biological function in the performance.In short, PQQ can protect cells from free radical attack by directly scavenging free radicals and mobilizing other antioxidant mechanisms, even promoting the synthesis of SOD . PQQ has some radiation resistance on theγ-irradiation of cells and mouse. At the same time, it can speed the apoptosis of radiation-damaged tumer cells and inhibit tumor cells growth.
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