环磷酰胺对豚鼠自身免疫性感音神经性聋听功能的影响

Effects of Cyclophosphamide Pretreatment on Hearing in Guinea Pigs with Autoimmune Sensorineural Hearing Loss

目的探讨环磷酰胺在制备豚鼠自身免疫性耳聋动物模型中的作用。方法白色红目豚鼠30只,配对设计分成3组各10只。实验组豚鼠腹腔注射环磷酰胺(150mg/kg)进行预处理,2 d后,每只豚鼠将粗制内耳抗原(crude in-ner ear antigens,CIEAgs)400μg·(0.2ml)-1加等量完全弗氏佐剂进行后足垫、背部皮内多点注射免疫;对照1组用CIEAgs 400μg·(0.2ml)-1加等量完全弗氏佐剂免疫动物;对照2组仅行环磷酰胺预处理。所有动物免疫前、免疫后7、14、21d,接受听性脑干诱发电位(auditory brain-stem response,ABR)检测。结果免疫前所有豚鼠ABR反应阈均值为29.50±5.56dBSPL,免疫后7天实验组、对照1及对照2组ABR反应阈分别为52.50±12.72、36.50±11.25、31.50±3.37;免疫后14天时三组反应域分别为58.50±14.79、33.25±8.93、30.50±3.69 dBSPL;免疫后21天分别为46.25±12.45、30.00±4.29、30.00±3.33 dBSPL。免疫后,实验组动物各时间段反应阈高于对照1,2组(P<0.01)。免疫前后组内比较,实验组免疫后7天、14天、21天反应域高于实验前(P<0.01);对照1组仅免疫后7天高于免疫前(P<0.05),14天、21天与免疫前相比差异无显著性,对照2组各时间段与免疫前相比差异均无显著性。结论将豚鼠用环磷酰胺进行预处理,可以显著提高粗制内耳抗原建立自身免疫性耳聋动物模型的成功率,并显著提高其ABR阈值,而环磷酰胺本身对豚鼠内耳听力没有显著影响。

Objective To study the effects of cyclophosphamide in guinea pigs with autoimmune deafness. Methods Guinea pigs were randomly divided into three groups （10 in each）. One group of animals received intracutaneous inoculation of an emulsion consisting of equal parts of crude inner ear antigens （CIEAgs, 0.2 ml） and complete Freund’s adjuvant （CFA） at multiple sites two days after pretreatment with cyclophosphamide （Experimental Group）. The second group of animals received only inoculation of CIEAgs and CFA （Control Group #1）, and the rest animals received only cyclophosphamide pretreatment （Control Group #2）. Animals in all three groups received auditory brain-stem response （ABR） testing before and on Days 7, 14 and 21 after immunization. Results The mean ABR threshold across all animals was 29.50±5.56 dB SPL before immunization. After immunization, the threshold was 52.50±12.72 dB SPL, 36.50±11.25 dB SPL and 31.50±3.37 dB SPL on Day 7, 58.50± 14.79 dB SPL, 33.25 ± 8.93 dB SPL and 30.50 ± 3.69 dB SPL on Day 14, and 46.25 ± 12.45 dB SPL, 30.00 ± 4.29 dB SPL and 30.00±3.33 dB SPL on Day 21 or the experimental group, Control Group 1 and Control Group 2, respectively. The ABR thresh-old for the experimental group on all after immunization days was higher than those for the two control groups （P〈0.01） and than before immunization （P〈0.01）. The ABR threshold for Control Group 1 was higher than before immunization on post-im-munization Day 7 only （P〈0.05）, and the ABR threshold for Control Group 2 showed no significant post-immunization change. Conclusions After pretreatment with cyclophosphamide, single inoculation of CIEAgs-CFA emulsion can significantly in-crease ABR thresholds in guinea pigs.