Effects Of Aluminum On Chick Embryonic Development And Offspring Cognition

Objective: This research is to investigate the effects of aluminum exposure on cognitive behavior of the developing offspring and nerve injury, and to provide a theoretical basis in the application of aluminum in food and medicines.Methods: The five sets of experiments were conducted in this study. (1) Three different protocols of one-trial passive avoidance learning paradigm were conducted to select the best one suited for this study. (2) Different concentrations of aluminum were injected into the airspace of the eggs and the best one-trial passive avoidance learning paradigm was used to examine the restricted effect of prenatal aluminum exposure on memory consolidation in day-old chicks. (3) The balance ability and spontaneous movement of chicks were detected by other behavioral tests. (4) GFAAS (graphite furnace atomic absorption spectrometry) was used to detemine aluminum deposition in the brain tissue of chicks in the early postnatal period after prenatal aluminum exposure, biochemical methods were employed to monitor oxidative stress indicators in the chicks'brain, and the possible mechanisms of the influence of prenatal aluminum exposure on cognitive function were also examined. (5) Bilateral intracranial injections and oral administration were used to inject aluminum chloride into the chicks'body, and one-trial passive avoidance learning and detour learning were used to detect the role of early postnatal aluminum exposure on cognitive function.Results: (1) Prenatal exposure to high concentration of aluminum at 200 mM affected the hatch rate (only 3.5%). (2) Prenatal aluminum of 20 mM exposure did not affect the hatch rate, but affected short-term memory (STM),intermediate-term memory(ITM)and long-term memory (LTM); while prenatal aluminum of 2 mM exposure only affected long-term memory (LTM). (3) Prenatal aluminum of 20 mM exposure affected chick's balance ability, but did not affect the spontaneous activity. (4) Prenatal aluminum of 20 mM exposure led to aluminum deposition in the day-old chick brain, and the activities of MDA,T-AOC,NOS and GSH-PX were increased, while the SOD activity was reduced.(5) Exposure to aluminum (oral administration) significantly delays the detour learning.Conclusion: Early aluminum exposure on ontogeny has a strong cognitive damage on chicks.