Objective        To observe the expression of fibroblast growth factor receptor 3 (FGFR3) in spinal cord of rats with neuropathic pain after selective ligation of sciatic nerve branches.       Methods        Forty male SD rats were divided into control group (n=20) and surgery group (n=20). A rat neuropathic pain was established by ligation of sciatic nerve branches. Behaviors of rats in two groups were observed 1 d before and 1

3

5

and 7 d after operation. Mechanical pain threshold value in two groups was calculated. Co-expression of spinal astrocytes and glial fibrillary acidic protein (GFAP) in two groups was detected with immunofluorescence in 7 d after operation. Expression of FGFR3 protein at different time points in two groups was detected by Western blotting.       Results        No significant difference was found in mechanical pain threshold value between the two groups in 1 d before operation (P0.05). The mechanical pain threshold value was 6.67±2.12

3.17±0.99

2.33±0.65

and 1.75±0.31 respectively in surgery group and 12.75±2.83

12.33±2.84

12.08±2.57

and 11.50±2.65 respectively in control group in 1

3

5

and 7 d after operation (P0.05). The GFAP was positively expressed while the FGFR-3 was negatively expressed in spinal astrocytes of rats in 7 d after operation. The expression of FGFR3 protein was 0.192 8±0.013 0

0.214 6±0.021 4

0.294 6±0.025 1

0.266 4±0.027 3 respectively in control group and 0.280 4±0.015 3

0.328 2±0.026 3

0.567 7±0.027 0

0.528 8±0.032 8 respectively in surgery group in 1

3

5

and 7 d after operation (P0.05).       Conclusion      Down-regulation of FGFR3 expression in rats with pathological neuralgia may be involved in activation of GFAP

indicating that FGFR3 plays an important role in the occurrence and development of pathological neuralgia.