Objective: To explore the effect of siRNA-mediated inhibition of lymphocyte-specific protein tyrosine kinase (Lck) on pulmonary inflammation in a mouse model of asthma.
Methods: A total of 32 female BABL/c mice were used in the study. The mouse asthma model was established with ovabumin (OVA), and Lck specific siRNA or nonspecific siRNA was transfected through the tail vein before the first OVA challenge. Two days after the last challenge, mice were sacrificed and bronchoalveolar lavage fluid (BALF), plasma and lung tissue were collected. Levels of Lck mRNA and protein in lung were detected by quantitative real-time PCR and western blot. The levels of IL-4 and IgE in BALF and plasma were detected with ELISA.
Results: Lck specific siRNA significantly inhibited expression of Lck mRNA and protein in T cells. In vivo transfection of Lck siRNA down regulated the expression of Lck mRNA and protein in lung parenchymal homogenates. Sensitized mice treated with Lck siRNA prior to OVA challenge had fewer eosinophils in BALF and in lung sections and lower levels of IL-4 and IgE in BALF and plasma compared to those treated with nonspecific siRNA.
Conclusions: Pretreatment of OVA sensitized mice with Lck siRNA results in attenuation of pulmonary inflammation following OVA challenge. Inhibition of Lck gene expression should be investigated further as a potential therapy for asthma.
Keywords: IL-4; IgE; T lymphocyte; in vivo transfection.