The study aimed to explore the influence of Dexmedetomidine (Dex) on cognitive function and
inflammatory factors in rats after cardiac surgery under cardiopulmonary bypass (CPB). For this
purpose, 30 healthy male SD rats were reared in a quiet and clean environment with alternating light for
12 hours. They were rolled randomly into 3 groups, each with 10 rats, namely the control (Ctrl) group,
the experimental group, and the Dex group. The rats in the Ctrl were not treated, and the rats in the
experimental group were intraperitoneally injected with 50μg/kg saline. After that, cardiac surgery was
performed under CPB. Rats in the Dex group were injected with 50 μg/kg Dex intraperitoneally and
underwent cardiac surgery under CPB. The Morris water maze (MWM) experiment was performed to
test the learning and memory abilities and spatial positioning abilities of SD rats. Enzyme-linked
immunosorbent assay (ELISA method) was adopted to detect the contents of TNF-α, IL-6, and IL-1β.
Fluorescence quantitative PCR was applied to determine the mRNA expression levels of TNF-α, IL-6,
and IL-1β in the hippocampus. Results showed that in the MWM experiment, in contrast with the Ctrl,
the escape latency of the experimental group and the Dex group after surgery were prolonged (P<0.05),
and the times they crossed platforms reduced (P<0.05). In contrast with the experimental group, the
escape latency of the Dex group shortened, and the times they crossed platforms increased. ELISA
suggested that in contrast with the experimental group, the concentrations of TNF-α, IL-6, and IL-1β in
the Ctrl decreased (P<0.05), and those in the Dex group decreased slightly. In the fluorescence
quantitative PCR experiment, in contrast with the experimental group, the mRNA expression levels of
TNF-α, IL-6, and IL-1β in the Ctrl increased, and those in the Dex group decreased slightly. Then Dex
can improve the cognitive dysfunction of rats undergoing cardiac surgery under CPB, and its molecular
mechanism may be to reduce the inflammation around the heart and hippocampus.