实验感染小鼠肉汁中抗旋毛虫抗体水平的研究

Anti-Trichinella Antibody Level in Muscle Juice of Experimentally Infected Mice

目的观察小鼠感染旋毛虫后不同时间肉汁中抗体水平的变化及其与血清抗体水平的相关性。方法将288只昆明小鼠随机分成3组(每组96只):轻度(A组)、中度(B组)及重度(C组)感染组,每鼠分别经口感染100、300、500条旋毛虫幼虫,感染后各组每周或隔周随机剖杀8只小鼠,收集血清和肉汁,用旋毛虫肌幼虫排泄物分泌抗原(ES抗原)ELISA检测血清及肉汁中抗体水平;另取30只小鼠,每鼠感染500条旋毛虫幼虫,感染后6周剖杀,制备肉样,用ELISA检测4℃及-20℃保存不同时间后的肉汁中抗体动态水平。结果轻度、中度和重度感染组小鼠分别在感染后4、3和3周开始从肉汁中检出抗体,抗体阳性率分别为87.5%、50%和87.5%;3组小鼠的肉汁抗体阳性率均随感染后时间的延长而逐渐升高,分别在感染后6、4和4周达100%,抗体水平均在感染后8周达高峰,吸光度(A490值)分别为0.43、0.49及0.52,之后肉汁中抗体水平稍有下降,但感染后第18周抗体阳性率仍均为100%,A490值分别为0.35、0.41及0.46。3组小鼠感染后不同时间肉汁与血清抗体水平均具有相关性(r100=0.940,r300=0.970,r500=0.983,P<0.05)。感染旋毛虫小鼠肉样在4℃保存7d和1d的抗体水平A490值均为0.53(F=0.250,P>0.05)。在-20℃保存8周和1周的肉汁抗体水平A490值分别是0.46和0.50,保存8周的肉汁抗体水平与1周的相比无明显下降(F=2.273,P>0.05);虽然保存10周的肉汁A490值已降至0.43,与保存1周的相比差异有统计学意义(F=15.675,P<0.05),但抗体阳性率仍为100%并持续至实验结束时(保存20周)。结论动物死亡或屠宰后不能采集血清时,可从新鲜、冷藏及冷冻胴体采集肉汁代替血清进行抗旋毛虫抗体的检测。

Objective To detect the anti-Trichinella antibody level in muscle juice of experimentally infected mice and their correlation with serum antibodies. Methods Two hundred and eighty-eight Kunming mice were randomly divided into 3 groups （96 mice each）, each mouse was inoculated with 100, 300 or 500 muscle larvae of T.spiralis, respectively. Anti-Trichinella antibodies in serum and muscle juice taken weekly up to 18 weeks post-infection （wpi） were detected by ELISA using T.spiralis muscle larval excretory-secretory （ES） antigens. Thirty mice were inoculated with T. spiralis muscle larvae（500 larvae each）. The muscle samples taken in 6 wpi were kept in plastic containers and conserved at 4 ℃for 7 days or at -20 ℃ for 20 weeks for detecting anti-Trichinella antibodies later. Results Anti-Trichinella antibodies in muscle juice of the mice infected with 100, 300 or 500 larvae were detected in 4, 3 and 3 wpi, with antibody positive rate of 87.5%, 50% and 87.5% respectively. In the three groups of mice, the antibody positive rate of muscle juice increased gradually after infection and up to 100% in 6, 4 and 4 wpi, and the antibody level reached its peak in 8 wpi with an absorbance value of 0.43, 0.49 and 0.52 respectively. Thereafter, the antibody level decreased slightly, but the positive rate was still 100% and lasted to 18 wpi when the experiment was ended. The antibody level in muscle juice showed significant positive correlation with serum antibodies at different time intervals after infection in three groups （r100=0.940, r300=0.970, r500=0.983, P〈0.05）. The absorbance value of muscle samples conserved at 4 ℃ for 7 d and 1 d was the same （0.53） （F=0.250, P〉0.05）, and those conserved at -20 ℃ for 8 wk and 1 wk was 0.46 and 0.50 respectively, showing that the antibody level in muscle juice did not decreased considerably after the muscle samples were frozen at -20 ℃ for 8 weeks （F=2.273, P〉0.05）. The absorbance value of Trichinella-infected muscle conserved at -20 ℃ for 10 wk decreased to 0.43, with significant difference from that conserved at -20 ℃ for 1 wk, but the positive rate was also 100%, and antibodies were detected in all muscle samples conserved at -20 ℃ for 20 weeks when the experiment was ended. Conclusion When animals died or were slaughtered and serum samples could not be collected, muscle juice can be collected from fresh, cool and frozen meat and used as a substitute sample for detecting anti-Trichinella antibodies.