Studies On Related Mechanisms And Age- And Sex-related Difference Of Learning And Memory Impairment In Rats Induced By Aluminum

[Objective] The mechanisms of learning and memory impairment and age-related and sex-related difference in rat induced by aluminum were studied, to provide the important and scientific basis for the specific prevention of aluminum intoxication and the improvement of Al-exposed workers life quality. [Methods] 1. SD rats, which are different in age and sex, were exposed to aluminum by intraperitioneal injection A1C13 solution for 60 days at different doses. After exposure, the step-down test was performed to measure the learning and memory abilities of rats, and the changes of pathological state in cerebrum were observed by optical and electron microscope. The aluminum content in brain and some neuro-biochemical changes were detected. 2. The expression of Bcl-2 in sub chronic Al-exposed rats' brain and the expression of c-Fos in both sub chronic and acute aluminum-exposed rats' brain were measured respectively by immno-histochemical method,aimed to discuss the mole mechanism of learning and memory deficit induced by aluminum. [Results] 1. Results of MANOVA show that the effect of age on the alterations of learning and memory abilities, pathological state in cerebrum, and all neuro-biochemical items is significant. However, the difference between female and male rats isn't significant statisticlly. Results of correlation analysis indicate that there is positive correlation between the dose of aluminum and the changes of MAO-B, MDA or other items in adult rats, but not in young rats. With increased dose, the latency of passive avoidance of adult rats shorten and the number of performing error increased obviously (P<0.01); activities of MAO-B and ATPase become stronger obviously (P<0.01), content of MDA increased (P<0.01), and activities of AChE and SOD decreased (P<0.05); the alteration of NO and NOS isn't significant (P>0.05). 2. Compared with homologous control group, the expression of Bcl-2 of rats' brain treated with subchronic aluminum exposure and the expression of c-Fos ofrats' brain treated with subchronic and acute aluminum exposure were stronger significantly. [Conclusion] 1. The impairment of learning and memory induced by aluminum is related to age and not to sex. It is more serious in adult rats than in younger. 2. Aluminum can affect learning and memory by many mechanisms. It can interfere with the course of degradation and transport of neural transmission and promote LPO, both of them may be the important mechanisms. Moreover, bcl-2 and c-fos probably are involved in the neurotoxicity of aluminum and playing an important regulation role in this process.