Pyrroloquinoline quinine prevents aluminum-induced cognitive deficit in rats

Pyrroloquinoline quinine (PQQ), an essential nutrient, antioxidant, has been reported to be promised in the treatment of neurological and psychical disorders. Aluminum, a well-known neurotoxin, has been suggested to be a contributing factor in Alzheimer's disease. In this study we investigated the possible effect of PQQ on aluminum-induced cognitive impairment in rats. Rats were exposed to aluminum chloride (100 mg/kg/day) and PQQ (0.2, 2 and 20 μg/kg/day) for 60 days. Cognitive functions and behaviour were evaluated using Morris water maze, swimming and passive avoidance tests. The locomotor functions in animals were assessed using the open field test. Motor coordination was assessed by the rota-rod test. Moreover, amino acid-like neurotransmitters including Glu, Gly, GABA and Asp in the plasma were determined by HPLC using o-phthalaldehyde as derivatization reagent. Results showed that 2μg/kg PQQ was found to cause significant enhancement of memory in the aluminum-exposed rats. Plasma indicated that the levels of Asp and Glu in the plasma of AD model were significantly higher than those in control group. This study showed that PQQ could prevent the cognitive deficit of aluminum-induced if used in appropriate doses, but the possible pharmacological and molecular mechanisms should be further explored.