ABSTRACT
Objective To establish an animal model of aging,to observe changes related to cognitive impairment and depression-like behavior,and to explore the mechanisms of the two diseases caused by the model.Methods Male Sprague-Dawley (SD) rats were treated with D-galactose and alchlor;after simultaneous administration of both drugs,their learning and memory abilities were assessed using the Morris water maze test.The depression-like behavioral changes were observed in the forced swimming test.Golgi staining was performed to observe the development of hippocampal neurons;oxidative stress index changes in superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels were analyzed in the hippocampus.Results Compared with a control group,rats in the model group showed reduced escape latency (P ＜ 0.05) from the platform in the water maze,reduced residence time on and a reduced number of times passing through the platform (P ＜ 0.05);the real time in the water during the forced swimming test was significantly prolonged (P ＜ 0.01).Golgi staining indicated that dendritic spine density in the hippocampus in model rats was decreased (P ＜ 0.01),as was hippocampus SOD activity (P ＜ 0.05),while MDA levels were increased (P ＜ 0.05).Conclusion We established a new animal model of aging with cognitive impairment and depression.The common disease mechanisms of these two diseases might be related to the destruction of the nervous system during the process of overload caused by free radicals and the resulting metabolic imbalance.
ABSTRACT
Through the analysis of Shenyang Medical College student's scientific research from 2007 to 2016, college student's scientific research has played an important role in promoting the cultivation of innovative talents, it has been an effective way that students understand the process of scientific research, cultivate scientific research ability, and that scientific research promotes teaching in university. College student's research should enhance the scientific and feasibility of the project selection, cultivate students the spirit of independent scientific research.
ABSTRACT
BACKGROUND:Whether plumbum(Pb) exposure induced learning and memory disorder in animals is correlated with the changes of the activity of protein kinase C(PKC) in the brain tissue? OBJECTIVE:To investigate the alterative rules of PKC activity in the brain tissue of rat in development stage under chronic exposure of Pb and its effects on the memory development of the mice. DESIGN:A randomized controlled study employing experimental animals as subjects. SETTING: Cellbiology Key Laboratory of the Ministry of Health,China Medical University. MATERIALS:The study was conducted in the Laboratory of Biochemistry and Molecular Biology of China Medical University. Totally 72,5- 6 weeks old Kunming mice were selected. METHODS:Lead acetate of different concentration was used to feed female mice after copulation.Fetal mice contacted Pb through breast feeding and drinking water.Fetal mice were executed separately on 1st day(P1),8th day(P8),15th day(P15),22nd day(P22), and 30th day(P30) after birth for brain tissue harvesting.PCK activity in the brain tissue of the mice exposed to Pb was detected in vitro by[γ 32P] ATP.Budding mice were exposed to lead acetate of different concentration for the observation of the effects of Pb in difference concentration on the memory of the mice through memory behavioral training and test by passive avoidance response experiments. RESULTS:PKC activity detection indicated that PKC activity in brain of Pb exposed budding mice during initial growth stage was higher than normal,while it was lower than normal during advanced stage of growth.High concentration Pb had relative stronger inhibition on PKC activity.Memory behavioral training indicated that low concentration Pb would induce elevation of memory curve in the initial stage of the development in mice but reduction of memory curve in middle and long term.The increase of Pb concentration would reduce memory curve. CONCLUSION:Pb has inhibitive effects on the development of PKC activity in brain tissue of mice:the higher the Pb concentration is, the more significant the inhibition is.Low concentration Pb seems to have stimulatory effects on memory in short period while long term exposure to Pb would induce memory inhibition.The inhibitive effect of high concentration Pb is more significant.Pb has certain correlation with PKC activity in brain tissues of budding mice and memory function.