Effects of electroacupuncture on cognitive function and learning and memory of mice exposed to ionizing radiation

Objective To investigate the effects of electroacupunctures at Baihui, Fengfu, and Shenshu on the cognitive function and learning memory of mice exposure with ionizing radiation. Methods C57BL/6J (30-day old) mice were randomly divided into 10 groups consisting of the control group, X-ray exposure groups (4, 8 and 16 Gy), electroacupuncture-nonacupiont (E-nonA) groups (4, 8 and 16 Gy) and electroacupuncture-acupiont (EA) groups (4, 8 Gy and 16 Gy), with 10 mice assigned to each group. The mice were irradiated (IR) on the left cerebral hemisphere with doses of 4, 8 and 16 Gy. Some mice were electroacupunctured for 3 courses of treatment. Using weight as a measurable parameter, the open-field test and Morris water maze test were used to evaluate the curative effects. Results Compared with the control group, the weights of mice in the exposure groups (8 and 16 Gy) significantly decreased (t=2.917, 9.650, 3.043, 2.882, P<0.05) at 7 and 14 d, while the weights of the E-nonA (8 and 16 Gy) and EA groups (8 and 16 Gy) were not significantly altered. Compared to the model groups (8 and 16 Gy), the weights of EA groups (8 and 16 Gy) significantly increased (t=6.602, 5.409, 19.660, 2.975, P<0.05). In the open-field test, the crossing times and the rearing time of exposure model groups (8 and 16 Gy) significantly decreased compared to the control group (t=2.183, 2.119, 2.369, 2.231, P<0.05). Compared with model groups (8 and 16 Gy) and E-nonA groups (8 and 16 Gy), the crossing times and rearing time of the EA groups were significantly increased (compared with model: t=8.914, 2.727, 4.325, 4.178, P<0.05; compared with E-nonA: t=4.030, 3.014, 2.150, 4.771, P<0.05). In the Morris water maze, compared with the control, the latent period of model group (4 Gy) was significantly increased and the crossing times significantly decreased(t=4.544, 3.422, P<0.05); compared to model and E-nonA groups (4 Gy), the latent period of EA group significantly increased (compared with model: t=2.877, P<0.05; compared with E-nonA: t=3.001, P<0.05). At day 2 and 3, the latent period of model groups (8 and 16 Gy) significantly increased (t=2.544, 3.706, 3.796, 7.934, P<0.05) and the crossing times (t=2.120, 2.393, P<0.05) significantly decreased, resident time in target area of model group (8 Gy) was significantly decreased (t=2.543, P<0.05) compared to the control group. Compared with model and E-nonA groups (8 and 16 Gy), the latent period of EA gourps significantly decreased (compared with model: t=5.404, 7.869, 4.104, 15.590, P<0.05; compared with E-nonA: t=2.938, 7.955, 6.566, 10.350, P<0.05) while the through times and resident time in target area significantly increased in the EA group (8 Gy) (compared with model: t=2.673, 2.613, P<0.05; compared with E-nonA: t=3.345, 2.179, P<0.05). Conclusions Irradiation with a dose higher than 8 Gy could induce mice brain injury. Electroacupuncture can alleviate the radiation damage of cognitive function as well as learning and memory functions in mice. Key words: Electroacupuncture; Ionizing radiation; Cognitive function; Learning and memory