禽致病性大肠杆菌O78对边鸡血清细胞因子水平的影响

The effect of avian pathogenic Escherichia coli O on serum cytokine level of Bian chicken

为了研究禽致病性大肠杆菌O78对边鸡血清细胞因子水平的影响,试验将112只30日龄边鸡分为2组:对照组7个处理,每个处理8只,腹腔注射无菌生理盐水;试验组7个处理,每个处理8只,腹腔注射50%致死浓度的禽致病性大肠杆菌O78菌悬液。试验期为7 d,分别于第0,0.5,1,1.5,3,5,7天这7个不同时间点,采用观察记录法和酶联免疫吸附试验法(ELISA)对感染禽致病性大肠杆菌O78边鸡的临床症状、死亡数量、血清细胞因子[免疫球蛋白、白细胞介素(IL)、γ干扰素(IFN-γ)、肿瘤坏死因子-α(TNF-α)]水平进行研究。结果表明:试验组边鸡感染禽致病性大肠杆菌O78后第0.5~1.5天出现临床症状;第1.5~3天临床症状加重,部分鸡死亡;第3~5天边鸡死亡数量增加,但未死亡边鸡的精神状态出现好转;第7天未再出现死亡,边鸡整体状态恢复正常。试验组第1,1.5,3天免疫球蛋白水平均极显著低于对照组(P<0.01),第1,1.5天IL-2、IL-4、IL-6水平均极显著高于对照组(P<0.01),第1,1.5,3天IL-8、IL-10、IFN-γ、TNF-α水平均极显著高于对照组(P<0.01)。试验组第0.5~1.5天免疫球蛋白水平持续降低,第1.5天降至最低水平,从第3天开始逐渐升高;第0.5~1.5天IL-2、IL-4、IL-6、IL-8、IL-10、IFN-γ、TNF-α水平持续升高,第1.5天升至最高水平,从第3天开始逐渐降低。说明边鸡感染禽致病性大肠杆菌O78后第0~7天临床症状出现规律性变化,免疫球蛋白水平先降低后升高,白细胞介素、IFN-γ和TNF-α等先升高后降低,其中第1.5天时感染最严重,第3天后开始恢复。

In order to study the effect of avian pathogenic Escherichia coli O78 on the serum cytokine levels of Bian chicken, 112 30-day-old Bian chickens were divided into 2 groups. 7 treatments were in the control group, 8 chickens in each treatment, by intraperitoneal injection of sterile saline;and 7 treatments were in the test group, 8 chickens in each treatment, by intraperitoneal injection of avian pathogenic E. coli O78 suspension of 50% lethal concentration. The test period was 7 days;at 0,0.5,1,1.5,3,5,7 d 7 different time points, the clinical symptoms, number of deaths, serum cytokine immunoglobulin, interleukin(IL),interferon-γ(IFN-γ) and tumor necrosis factor-α(TNF-α) levels of chickens infected with avian pathogenic E. coli O78 were detected by observation recording method and enzyme-linked immunosorbent assay(ELISA). The results showed that the chickens in the test group infected with avian pathogenic E. coli O78 on the first 0.5 to 1.5 days showed clinical symptoms;the clinical symptoms were severe on the 1.5 to 3 days, and some chickens died;on the 3 to 5 days, the number of chicken deaths increased but the mental state of the undead chicken had improved;there were no dead chickens on the 7 th day, and the overall condition of the Bian chickens returned to normal. The immunoglobulin levels of the test group on day 1,1.5,and 3 were extremely significantly lower than those of the control group(P<0.01);the levels of IL-2,IL-4,and IL-6 on day 1,1.5 were extremely significantly higher than the control Group(P<0.01);the levels of IL-8,IL-10,IFN-γ,and TNF-α on day 1,1.5,and 3 were significantly higher than those of the control group(P<0.01). The immunoglobulin levels of the test group continued to decrease on day 0.5-1.5,and dropped to the lowest level on day 1.5, and gradually increased from day 3;IL-2,IL-4,IL-6,IL-8,IL-10,IFN-γ,and TNF-α levels continued to increase on day 0.5-1.5, and reached the highest level on day 1.5,and gradually decreased from day 3. The results indicated that the clinical symptoms of Bian chickens were infected with avian pathogenic Escherichia coli O78 on the 0 th to 7 th days. The levels of serum cytokine, immunoglobulin first decreased and then increased, while the levels of interleukin, IFN-γ and TNF-α first increased and then decreased. The infection was the most serious on day 1.5,and it started to recover after the third day.