Effects Of Flurbiprofen Axetil On Behavior And Fos-protein In Spinal Dorsal Horn Of Incision-induced Pain In Rats

Objectives:(1)To study the feasibility of postoperative analgesia of the flurbiprofen axetil through nociceptive behaviors in the incision-induced rats;(2)To observe the expression of Fos in the spina dorsal horn in the incision-induced rats so as to investigate the preemptive analgesia of flurbiprofen axetil.Methods:32 awake rats weighing 140-190g were randomly divided into four groups,each group included 8 rats.Normal controlling group: isoflurane was inhaled for 5 min but no incision was made;Lipoid microballoon group:vena caudalis injected Lipoid microballoon 3ml/kg 15 min prior to the incision in the plantar of the right hind paw;Preoperative administration group:vena caudalis injected flurbiprofen axetil 30mg/kg 15 min prior to the incision;Postoperative administration group:vena caudalis injected flurbiprofen axetil 30mg/kg 15 min inferior to the incision.Incision of 1 cm long was made in the plantar region of left hindpaw parallel to the muscle under isoflurane anesthesia according to the method of Brennan. Pain behavior was assessed by a cumulative pain score.Stepping behavior was evaluated 0-60 min after hind paw incision.One and half an hour later, rats were extracted blood from heart then perfused,L4-L5 sections of spinal cords were dissected,sliced and processed by immunostained with a rabbit polyclonal antiserum directed against c-fos.The changes of FLI positive neurons in the dorsal horn were studied.Results:(1)Rats in the normal controlling group which no incision was made had not changes of behavior.The cumulative pain score were 0.17±0.75.Rats in the lipoid microballoon group the cumulative pain score were 18.00±1.41.The cumulative pain score were significantly increased after plantar incision in the preoperative and postoperative administration group(P<0.05)compared with the normal controlling group,and significantly decreased compared with the lipoid microballoon group (P<0.05).The cumulative pain score of the preoperative administration group was lower than the postoperative administration group and the difference was significant(P<0.05).(2)Incision-induced FLI positive neurons were mainly distributed in the incision ipsilateral laminaⅠ,ⅡandⅤ,Ⅵof spinal dorsal horn.Rats in the normal controlling group in which no incision was made the average numbers of FLI positive neuron were the least.In the lipoid microballoon group,lots of FLI positive neurons were observed in the ipsilateral spinal dorsal horn of L4-L5 to the incision.The most of them were located in the lamina superficialis of spinal dorsal horn.The average numbers of FLI positive neuron in the spinal dorsal horn of the preoperative and postoperative administration group were less than the lipoid microballoon group and the differences were significant(P<0.05).The average numbers of FLI positive neuron in the spinal dorsal horn of preoperative administration group was significantly less compared to postoperative administration group(P<0.05).Conclusion:(1)To the extent the incision-evoked nociceptive behaviors were suppressed by administration of flurbiprofen axetil;(2) Flurbiprofen axetil can suppress the expression of c-fos in the spinal dorsal horn and the response of spinal dorsal horn neuron to the harmgul stimulus. Flurbiprofen axetil has the effects of preemptive analgesia.