[Analgesic effect of Fengshi Qutong Capsules on mice with chronic inflammatory pain caused by complete Freund's adjuvant].

The aim was to observe the analgesic effect of Fengshi Qutong Capsules(FSQTC) on chronic inflammatory pain in mice, and investigate its effect on p-ERK/COX-2 signal molecular activity. A model of chronic inflammatory pain was induced in mice by complete Freund's adjuvant(CFA). The mice were divided into normal control group, model group, model+FSQTC 0.3, 0.6 and 1.2 g·kg~(-1 )groups, model+positive control drug ibuprofen(IBP, 0.34 mg·kg~(-1)·d~(-1)) group, and normal control+ FSQTC 1.2 g·kg~(-1)group. FSQTC or IBP was given once a day by oral administration. Standard Von Frey fiber was used to evaluate the mechanical pain threshold, and the acetone stimulation was used to induce inflammatory plantar and observe the cold pain reaction scores. The mechanical pain threshold and cold pain reaction scores were observed before administration and 1, 2, 3, 4, 6 h after administration on the first day, as well as 3 h after administration on the 3 rd to 7 th day. The protein levels of PGE_2, COXs-1,2 and p-ERK in the spinal cord of the inflammatory foot and lumbar 4-5 were detected by enzyme-linked immunosorbent assay, Western blot, immunohistochemistry and immunofluorescence. The results showed that the mechanical pain threshold of the model group decreased and the cold pain reaction score increased as compared with the normal group. FSQTC application could dose-dependently increase the mechanical pain threshold and decrease the cold pain reaction score. The effect lasted for 6 h, most significant at 3 h. The effect of ibuprofen was similar to that of the 0.6 g·kg~(-1) dose group. In addition, FSQTC could reduce the abnormally increased protein content of PGE_2, COX-2 and p-ERK in the inflammatory foot and/or spinal cord of the model group, and the effect was most significant in middle and high dose groups. However, it had no effect on COX-1 in the inflammatory foot and spinal cord of mice. The results suggest that FSQTC has ob-vious analgesic effect on chronic inflammatory pain in mice, which may be related to inhibition of p-ERK/COX-2 signaling pathway.