Objective: To explore the effects of Houttuynia Cordata on expression of human β-defensin-2 (HBD-2) in pulmonary epithelial cells (SPC-A-1) in vitro, and to observe the correlationship between the level of HBD-2 mRNA and the concentrations or treatment times of Houttuynia Cordata.
Methods: The SPC-A-1 cells were cultured with different concentrations of Houttuynia Cordata in vitro, including 0, 12.5, 25, 50, 100 and 200 μg/ml. And then, the SPC-A-1 cells were cultured with the optimal concentration of Houttuynia Cordata in different lengths of time, including 1, 2, 4, 8, 16 and 24 hours. After the treatment, the mRNA level of HBD-2 in pulmonary epithelial cells was detected by means of semi-quantitative reverse transcription polymerase chain reaction (RT-PCR).
Results: After being cultured with Houttuynia Cordata, the expression of HBD-2 mRNA had positive correlation with the stimulus concentrations (r_s=0.829, P=0.042) and stimulus time (r_s=0.914, P=0.003). The highest expression of HBD-2 mRNA was induced by 100 μg/ml Houttuynia Cordata after 8-hour treatment. In comparison with the normal control group and the interleukin-1β group, 100 μg/ml Houttuynia Cordata could significantly up-regulate the expression of HBD-2 mRNA in SPC-A-1 cells after 8-hour treatment (P<0.01).
Conclusion: Houttuynia Cordata can up-regulate expression of HBD-2 mRNA in SPC-A-1 cells, and the highest expression level of HBD-2 mRNA can be obtained by culture with 100 μg/ml Houttuynia Cordata for 8 hours.

Key words: Houttuynia Cordata, beta-defensins, human pulmonary cell