Objective To study the effects of subchronic aluminum exposure on learning and memory and the expression of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor in rats.
Methods Thirty-six health adult SD male rats were divided into 4 groups at random, i.e. control, 15 μmol/kg Al(mal)3, 30 μmol/kg Al(mal)3, and 45 μmol/kg Al(mal)3 groups. After intraperitoneal injection of aluminum-maltolate for 8 weeks, the learning and memory abilities of rats were tested by the Morris water maze, the pathology changes of hippocampus were observed with hematoxylin and eosin (HE) staining, and the expressions of GluR-1, GluR-2, and GluR-3 subunits of AMPA receptor in hippocampus were detected by Western blot.
Results With the increase of exposure dose, the pyramidal cells in hippocampus significantly decreased in number and were disarranged, with swollen nuclei and disordered axon guidance co-occurred. In the place navigation test, compared with the control group (29.86& #177;10.34)s, the latency to find the platform of the 30 μmol/kg group (44.75& #177;12.82)s and the 45 μmol/kg group (46.48& #177;8.12)s were statistically increased (P<0.05). In the spatial probe test, compared with the control group (43.11& #177;15.72)s, the time spent in target quadrant of the 30 μmol/kg group (34.70& #177;9.25)s and the 45 μmol/kg group (32.93& #177;11.28)s were significantly decreased (P<0.05). Compared with the control group (0.92& #177;0.09, 0.83& #177;0.26), the expressions of GluR-1 and GluR-2 of the 45 μmol/kg group (0.41& #177;0.14, 0.42& #177;0.09) were significantly decreased (P<0.05).
Conclusion Subchronic exposure to aluminum could damage the learning and memory of rats, and is possibly related to the expression decrease of AMPA receptors.
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