Mechanism of dexmedetomidine preconditioning on spinal cord analgesia in rats with functional chronic visceral painPurpose: To analyze the effect and mechanism of dexmedetomidine (DEX) analgesia pretreatment on functional chronic visceral pain in rats.
Methods: Rats were divided into six groups: W1, W2, W3, W4, W5, and W6. The behavioral changes and electrophysiological indexes of rats in each group before and after DEX treatment were detected.
Results: The levels of abdominal withdrawal reflex (AWR) in W5 and W6 groups were significantly lower than those in group W3, while the levels of thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) were significantly higher than those in group W3 (p < 0.05). The electromyographic signals of W1, W5, and W6 groups showed little fluctuation, while those of groups W2, W3, and W4 showed obvious fluctuation. TLR4 mRNA expression, IRF3, P65, and phosphorylation levels in W4, W5, and W6 groups were significantly lower than those in group W2 (p < 0.05).
Conclusions: Dexmedetomidine epidural anesthesia pretreatment could significantly inhibit visceral pain response in rats with functional chronic visceral pain, and its mechanism was related to the activation of TLR4 in spinal dorsal horn tissue of rats and the activation inhibition of IRF3 and P65 in the downstream key signals.
Key words
Dexmedetomidine; Functional Chronic Visceral Pain; Toll-Like Receptor 4; Analgesia; Electrophysiological Indexes
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* indicates that the difference is statistically significant compared with group W3 (p < 0.05).# compared with W6 group, the difference is statistically significant (p < 0.05).
* indicates that the difference is statistically significant compared with the group W3 (p < 0.05).# indicates that the difference is statistically significant compared with the group W6 (p < 0.05).
(a) EMG of rats in group W1; (b) EMG of rats in group W2; (c) EMG of rats in group W3;(d) EMG of rats in group W4; (e) EMG of rats in group W5; (f) EMG of rats in group W6.
* indicates that the difference is statistically significant compared with group W1(p < 0.05) * compared with group W4, the difference is statistically significant (p < 0.05).
* indicates that the difference is statistically significant compared with group W3 (p < 0.05).
* indicates that the difference is statistically significant compared with group W1 (p < 0.05)# indicates that there is significant difference in group W2 (p < 0.05).
* indicates that the difference is statistically significant compared with group W1 (p < 0.05) # indicates that there is significant difference in group W2 (p < 0.05).