TNF and periodontitis: Cytokines such as IL-1β and TNFα have been reported to play destructive roles on soft tissue and bone resorption.32 Our study showed that the transcription of IL-1βand TNF-α were upregulated in gingival and spleen cell and tissues in the presence of P. gingivalis with ligation, which agrees with published data associating periodontitis with increases of IL-1β and TNF-α,32 essential to mediate the pathogenesis of tissue destruction and bone loss.