山奈酚对小鼠迟发型超敏反应的免疫抑制作用

Immunosuppressive effect of kaempferol on delayed type hypersensitivity in mice

目的探讨山奈酚(kaempferol,KA)对二硝基氟苯(dinitrofluorobenzene,DNFB)诱导的小鼠迟发型超敏反应(delayed type hypersensitivity,DTH)的免疫抑制作用。方法将BALB/c小鼠按体重随机分为6组:生理盐水对照组、DTH模型组、环磷酰胺(cytoxan,CTX)组(20 mg/kg)、KA低剂量(2 mg/kg)、中剂量(4 mg/kg)、高剂量(8 mg/kg)组,每组10只,用DNFB致敏,同时给药,连续给药7 d。致敏后第5天于小鼠右耳背涂1%DNFB 5μl诱发DTH,左耳涂等量的丙酮/橄榄油溶剂作为对照。连续给药7 d后,称量小鼠体重及脾脏和胸腺湿重,计算脾脏指数和胸腺指数;DNFB激发后48 h,剪下小鼠左右耳廓,称重,计算小鼠耳廓肿胀度,并将剪取的右耳耳廓制成冰冻切片,光学显微镜下观察小鼠耳廓局部组织的病理变化;无菌取脾,制备脾细胞,MTT法检测经ConA刺激的脾淋巴细胞的增殖活力。结果 KA高剂量组能显著降低DTH小鼠的脾脏指数和胸腺指数(P<0.01或P<0.05);KA中、高剂量组能明显抑制DNFB所诱发的小鼠耳廓肿胀度(P<0.05或P<0.01);KA能明显减少DTH小鼠耳廓局部组织淋巴细胞的浸润,并抑制脾脏淋巴细胞的增殖(P<0.05或P<0.01)。结论 KA对DTH小鼠具有明显的免疫抑制作用,抑制淋巴细胞的增殖可能是其作用机制之一。

Objective To investigate the immunosuppressive effect of kaempferol（KA）on delayed type hypersensitivity（DTH）induced by dinitrofluorobenzene（DNFB）in mice.Methods BALB/c mice were randomly divided into physiological saline control,DTH model,cytoxan（CTX）（20 mg/kg）as well as low（2 mg/kg）,moderate（4 mg/kg）and high（8 mg/kg）dosage KA groups according to the bodyweight,ten for each,then sensitized with DNFB and treated with the corresponding drugs for 7 d.DTH was induced on day 5 after sensitization by smearing 5 μl of 1% DNFB onto the back of right ears of mice,while the left ears were smeared with acetone/olive oil solvent at an equal volume as control.The bodyweight as well as wet weights of spleen and thymus of the mice were measured 7 d after treatment,based on which the spleen and thymus indexes were calculated.The two ears of mice were weighed 48 h after induction with DNFB to calculate the swelling level,the prepared into frozen sections and observed for pathological change by optical microscopy.Spleens of mice were collected aseptically,from which splenocytes were prepared and determined for proliferation activity after stimulation with ConA by MTT method.Results KA at a high dosage decreased the spleen and thymus indexes of mice with DTH significantly（P ＆lt; 0.01 or P ＆lt; 0.05）,while that at moderate and high dosages inhibited the swelling of ears induced by DNFB significantly（P ＆lt; 0.05 or P ＆lt; 0.01）.Meanwhile,KA decreased the lymphocyte infiltration in local ear tissues of mice with DTH and inhibited the proliferation of splenic lymphocytes（P ＆lt; 0.05 or P ＆lt; 0.01）.Conclusion KA showed significantly immunosuppressive effect on DTH in mice by a possible mechanism of inhibiting the proliferation of lymphocytes.