Abstract: The purpose of this study was to explore the effect of different doses of cyclophosphamide（CTX）onyellow chickens were randomly divided into 4 groups（Control group，CTX20 group，CTX40 group，and CTX80 group）with 3 replicates per group and 10 in each replicate. All groups were fed with basic diet. The chickens in the CTX20，CTX40，and CTX80 groups were intramuscularly injected with 20，40，and 80 mg/kg BW of CTX at 19，20， and 21 days of age，and the control group was injected with the same amount of normal saline. Seven days after the last injection，15 chicks from each group were randomly selected to collect the bursa of Fabricius and serum for histological observation，Tunel，real ? time fluorescence quantitative PCR，and ELISA detection. The histological results showed that CTX treatment could induce the increase of space between the nodules of the bursa of Fabricius， the decrease of cell density in the medullary tissue，fibroplasia in the medullary region，the dissolution of the nucleus， the pyknosis of the nucleus，and the increase of necrotic cells. The Tunel test results showed that CTX could induce apoptosis of bursa cells（P<0.05），and the apoptosis rate in the CTX40 group was more than 35%. The results of real? time fluorescence quantitative PCR showed that the apoptosis ? related genes expressions of Bcl ? 2 and NF ?κB were significantly decreased，and the mRNA expressions of TNF?α and Caspase3 were significantly increased in the bursa of Fabricius by CTX treatment（P<0.05）. The results of serum ELISA showed that compared with the control group， the expression level of TNF?α and IFN?γ was significantly increased，and the expression level of IL?2 and IL?6 was significantly decreased（P<0.05）. These results indicate that the immunosuppression model of the chicken bursae of Fabricius was successfully constructed in this study，and 40 mg/kg CTX had the best effect. the immunosuppression of the bursa of Fabricius in Lingnan yellow chickensand to provide an animal model reference for further research on how to improve the immunity of the bursa of Fabricius. In this study，120 1?day ?old Lingnan

Key words: Cyclophosphamide, Lingnan yellow chicken, Bursa of Fabricius, Immunosuppression

摘要： 该研究旨在探究不同剂量环磷酰胺（CTX）对岭南黄鸡法氏囊免疫抑制的影响，为后 续探究如何提高法氏囊免疫力提供动物模型参考。该试验将120只1日龄岭南黄鸡随机分成4 组（对照组、CTX20组、CTX40组和CTX80组），每组3个重复，每个重复10只。所有组饲喂基 础日粮，CTX20组、CTX40组和CTX80组雏鸡在19、20、21日龄时分别肌肉注射20、40、80 mg/ kg BW的CTX，对照组注射等量的生理盐水，最后一次注射7天后，每组随机选取15只雏鸡无 菌采集法氏囊和血清进行组织学观察、Tunel检测、实时荧光定量PCR和ELISA检测。组织学观 察结果显示，CTX处理可以诱导法氏囊小结间空隙增大、髓质中细胞密度降低、髓质区纤维增 生、细胞核溶解、核固缩、坏死细胞数量增加等现象。Tunel检测结果显示，CTX可以诱导法氏 囊细胞凋亡（P<0.05），其中CTX40组内细胞凋亡率超过35%。实时荧光定量PCR检测结果显 示，CTX 处理可以诱导法氏囊内细胞凋亡相关基因 Bcl?2 和 NF?κB mRNA 表达量显著降低， TNF?α和Caspase3 mRNA 表达量显著上升（P<0.05）。血清ELISA 检测结果显示，与对照组相 比，CTX 处理可以诱导 TNF?α 和 IFN?γ 表达量显著上升，IL?2 和 IL?6 表达量显著降低（P< 0.05）。上述结果表明，该试验成功构建了雏鸡法氏囊免疫抑制模型，其中40 mg/kg CTX免疫 抑制效果最优。

关键词: 环磷酰胺, 岭南黄鸡, 法氏囊, 免疫抑制