CLDN1 and infection: The results demonstrated that HO and PD98059 increased and abrogated the reduced transcription of TJs (E-cad, occludin and claudin-1) caused by T. spiralis infection; and reduced and abolished the elevated transcription of claudin-2 caused by T. spiralis infection, further suggesting that RACK1 receptor and ERK1/2 pathway in gut epithelium play an important role for T. spiralis invasion at early stage of infection.