1. Guizhou Provincial Center for Disease Control and Prevention, Guiyang 550004, China; 2. Department of Parasitology, Guiyang Medical College, Guiyang 550004, China
Abstract:To learn the brain immunopathogenesis in mice infected with Toxoplasma gondii PRU strain with the cytokines in the tissue, 51 mice were grouped into the infected and the control. Thirty-three ICR mice were infected intraperitoneally with cysts, and 10 cysts in each, 18 mice were injected with PBS as control. Five mice from the infected and three from the control were sacrificed under anesthesia on 5 d, 10 d, 15 d, 20 d, 30 d, and 90 d post-infection (p.i.), and the brain tissues were collected for hematoxylin-eosin (HE) staining and RNA extraction followed by examination of IFN-γ, IL-4, IL-6, and TNF-α with real-time PCR. The rest of the tissues were subjected to ELISA for the cytokines detection. Comparing with the control, IFN-γ in the infected mice began to rise on 5 d, decreased to the lowest on 10 d, and then began to raise again p.i. TNF-α began to decrease obviously from 10 d to 15 d p.i, and reached its highest level on 30 d p.i. IL-6 increased on 5 d p.i, and then decreased to the lowest on 10 d p.i, then rose slightly and reached the highest on 30 d p.i. No remarkable alteration of IL-4 was noted. ICR mice infected with T. gondii PRU strain presented an obviously down-regulated expression of IFN-γ, IL-6 and TNF-α from 10 d to 15 d p.i, which might help the parasites survive from the host immune challenge. Additionally, the timing phase of cytokines expression may be responsible for the cyst formation and latent T. gondii infection.
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