关键词: 钙信号转导, 柔嫩艾美耳球虫, 子孢子, 硝苯地平, 三氟拉嗪, MDCK细胞

Abstract: 【Objective】 The objective of the study is to investigate the relationship between Ca2+ signal transduction and Eimeria tenella sporozoite invasion, and to reveal the mechanism of coccidiosis (E. tenella). 【Method】 An assay system in vitro was used to study the effects of E. tenella sporozoites invasion into MDCK cell by extracellular Ca2+ deficiency or Ca2+ inflow blocker (nifedipine) or calmodulin inhibitor (trifluoperazine). Viability of MDCK cells and lactate dehydrogenase in supernatant liquid was examined. 【Result】 The inhibition rate of E. tenella sporozoite invasion increased with the decrease of the Ca2+ concentration. At low Ca2+ concentration of 600 μmol•L-1, the rate of E. tenella sporozoite invasion (23.33%) was significantly (P＜0.01) lower than that of the control group. When extracellular environment was absent of Ca2+ absolutely, the inhibition rate rose to 53.18%. Either nifedipine or trifluoperazine could inhibit the E. tenella sporozoite invasion obviously (P＜0.01), the inhibition rate of 71.41% and 97.13% were achieved by 10 μmol•L-1 nifedipine and 50 μmol•L-1 trifluoperazine, respectively. The inhibition rate of 98.59% was reached by nifedipine and trifluoperazine together. The viability of MDCK cells with E. tenella sporozoite invasion exceeded 90%, and the data was not remarkably different compared with the control group (P＞0.05). The same is as the viability of lactate dehydrogenase in supernatant liquid. 【Conclusion】 Extracellular Ca2+ deficiency, calciumion inflow blocker (nifedipine) and calmodulin inhibitor (trifluoperazine) could inhibit the E. tenella sporozoite invasion of MDCK cells. The host cell activity was not affected by E. tenella sporozoite invasion.

Key words: Ca2+ signal transduction, E.tenella, sporozoite, Nifedipine, Trifluoperazine, MDCK cells