8-O-乙酰山栀子苷甲酸对慢性炎性痛模型大鼠的镇痛作用机制研究

目的:研究8-O-乙酰山栀子苷甲酸(8-OaS)对慢性炎性痛模型大鼠的镇痛作用机制。方法:将30只雄性SD大鼠分为假手术组(生理盐水)、模型组(生理盐水)和8-OaS低、中、高剂量组(3、10、30μg/kg),每组6只。除假手术组外,其余各组大鼠足底注射弗氏完全佐剂复制慢性炎性痛模型。造模成功后,各组大鼠鞘内给予相应药物,每天1次,连续给药7 d后,采用Von-Frey细丝检测各组大鼠足底疼痛阈值,计算各组大鼠疼痛阈值曲线下面积和8-OaS的半数有效剂量(ED50)。另取36只雄性SD大鼠分为假手术组(生理盐水)、模型组(生理盐水)和8-OaS组(给药剂量为ED50),同法造模及给药,然后采用免疫荧光组织染色法观察各组大鼠脊髓背角内离子钙结合衔接分子1(Iba-1)、磷酸化p38丝裂原激活的蛋白激酶(p-p38 MAPK)的阳性表达情况,采用Western blotting法检测各组大鼠脊髓背角内Iba-1、p-p38 MAPK、白细胞介素1β(IL-1β)、IL-6及肿瘤坏死因子α(TNF-α)的蛋白表达水平。结果:与假手术组比较,模型组大鼠足底疼痛阈值和曲线下面积均显著降低(P&...

Study on Mechanism of Analgesic Effect of 8-O-acetyl-safalinoside on Chronic Inflammatory Pain ModelRats

OBJECTIVE:To study the mechanism of analgesic effect of 8-O-acetyl-safalinoside(8-OaS)on chronic inflammatory pain model rats.METHODS:Totally 30 male SD rats were divided into sham operation group(normal saline),model group(normal saline),8-OaS low-dose,medium-dose and high-dose groups(3,10,30μg/kg),with 6 rats in each group.Except for sham operation group,other groups were given planter injection of Freund’s complete adjuvant to induce chronic inflammatory pain model.After successful modeling,the rats in each group were given corresponding drugs intrathecally,once a day,for 7 consecutive days.Then Von-Frey filaments were used to detect the planter pain threshold of the rats in each group;the area under the planter pain threshold curve of each group and the half effective dose(ED50)of 8-OaS were calculated.Another 36 male SD rats were divided into sham operation group(normal saline),model group(normal saline)and 8-OaS group(dose of ED50),and the modeling method and administration route were the same as above.Immunofluorescence histochemical staining was used to observe the positive expression of ionized calcium binding adapter molecule 1(Iba-1)and signal molecule phosphorylated p38 mitogen-activated protein kinase(p-p38 MAPK);Western blotting assay was used to determine the expression of Iba-1,p-p38 MAPK,IL-1β,IL-6 and TNF-αin spinal dorsal horn of rats.RESULTS:Compared with sham operation group,plantar pain threshold and area under the curve in model group were reduced significantly(P<0.01).Compared with model group,plantar pain threshold increased significantly after 5,6,7 days of administration in 8-OaS low-dose group(P<0.05),plantar pain threshold and area under the curve in 8-OaS medium-dose and high-dose groups were increased significantly(P<0.05 or P<0.01).Most of above indexes in each dose group of 8-OaS were signifficantly different,and ED50 of 8-OaS was 18.87μg/kg.Results of immunohistochemistry staining and Western blotting showed that p-p38 MAPK was mainly expressed in Iba-1 positive cells.Compared with sham operation group,the fluorescence density of Iba-1 and p-p38 MAPK in spinal dorsal horn,the expression of Iba-1,p-p38 MAPK,IL-6,IL-1βand TNF-αwere significantly increased in model group(P<0.05 or P<0.01).Compared with model group,the fluorescence density of Iba-1 and p-p38 MAPK in spinal dorsal horn,the expression of Iba-1,p-p38 MAPK,IL-6,IL-1βand TNF-αwere decreased significantly in 8-OaS group(P<0.05).CONCLUSIONS:Intrathecal administration of 8-OaS can effectively alleviate chronic inflammatory pain in rats.The mechanism may be related to the inhibition of the phosphorylation of p38 MAPK and the expression of IL-6,IL-1βand TNF-α.