Change in 5-hydroxytryptamine level in spinal dorsal horn in a rat model of tibial bone cancer pain / 中华麻醉学杂志

ABSTRACT

Objective To investigate the change in 5-hydroxytryptomine (5-HT) content in spinal dorsal horn in a rat model of tibial bone cancer pain (BCP). Methods Sixty female SD rats weighing 160-180 g were randomly divided into 3 groups ( n = 20 each) control group (group C), sham operation group (group S) and BCP group. BCP was induced by intra-tibial inoculation of 10 μl Walker 256 breast cancer cell suspension in group BCP, while group S received intra-tibial inoculation of 10 μl D-hank solution. Paw withdrawal threshold to mechanical stimulation with yon Frey filaments (MWT) was measured 1 d before (baseline) and at 3, 5, 7, 9, 11,14, 16, 18 and 21 d after breast cancer cell inoculation. At 1 d before and 7, 14 and 21 d after breast cancer cell inoculation, four animals in each group were sacrificed after measurement of MWT. Their lumber segments of the spinal cord were removed for assay of 5-HT content in spinal dorsal horn using HPLC with fluorescence detector.HE staining was used to detect the damage to the tibia. Correlation between the 5-HT content and MWT was analyzed. Results MWT was significantly decreased after breast cancer cell inoculation in group BCP ( P ＜ 0.05).Microscopic examination showed serious bone destruction of tibia at the injection site in group BCP, while no bone destruction was found in groups C and S. 5-HT content in spinal dorsal horn was significantly higher in group BCP than in groups C and S (P ＜ 0.05). There was strong negative linear correlation between 5-HT content in spinal dorsal horn and MWT ( r = - 0.973, P ＜ 0.05 ). Conclusion The 5- HT content in spinal dorsal horn is significantly increased in rats with tibial BCP and is involved in the development of BCP.