Objective:To observe the effects of chronic pain on the cognitive function of pregnant mice and their offspring by constructing the animal model of chronic pain in pregnant mice. Methods:The pregnant mice were divided into normal group, sham-operation group and chronic pain group (10 in each group). Aseptic complete Freund's adjuvant 100 μl (500 μg) was injected intracutaneously in the paw joint of pregnant mice to induce arthritis pain. Water labyrinth experiment was performed to evaluate the cognitive ability of the animals. Results:In the place navigation test, the average escape latency of the mice in chronic pain group were longer than that in sham operation group (P<0.001).In the spatial search experiment, the number of times of crossing the platform, the average swimming speed, the swimming time ratio and the swimming distance ratio staying in the original platform quadrant of the mice in the chronic pain group were less than those in the sham operation group (all P<0.05).At the third week after their offspring birth, the average escape latency of offspring mice in the chronic pain group was longer than that in the sham operation group(P<0.01), and the number of times of crossing the platform was less than that in the sham operation group (P<0.05).There was no difference in the average swimming speed, the swimming time ratio and the swimming distance ratio staying in the original platform quadrant between the offspring mice of the two groups (P>0.05). Conclusions:Chronic pain during pregnancy can lead to a decline in maternal cognitive ability and also affect the cognitive function of the offspring in infancy.
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