Abstract： AIM:To observe the effects of sevoflurance on pain behaviors and spinal cord astrocyes activation in a rat model of hind paw plantar incision.METHODS:One hundred adult healthy SD rats underwent a unilateral hind paw plantar incision after placidity anaesthesia.Eighty successful modle rats were divided at random into control and experimental groups(n=40).Rats underwent a unilateral hind paw plantar incision after placidity anaesthesia.Ten rats were selected randomly for each time point and were tested before operation,6 h,24 h,3 d and 5 d after operations.Pain score were calculated and the mechanical thresholds were measured by using yon Frey filaments.The tissue of the forth to sixth lunbar spinal cord was obtained,and then chage of glial fibrillary acidic protein(GFAP)was observed.RESULTS: The cumulative pain score in both groups had no significant different.The mechanical threshold decreased rapidly after operation in both groups,then iereased gradually.It came to normal in sevofluranee group but Was still lower in control group 5 d after operation.To control group,the GFAP immunoreactivity of ipsilateral opinal dorsal horn in the forth to sixth lumbar spinal cord began to enhance 6 h after operation and reached peak 3 d after operation.By contrast it enhanced slighfly and with no peak in sevoflrance group.CONCLUSION:Sevofluence may relieve mechanical hyperalgesia through inhibiting the activation of spinal cord astmcytes.