Objective        To determine the effects of tumor necrosis factor-α (TNF-α) on the biological behaviors of cultured fibroblasts and its relevant nuclear factor-κB (NF-κB).       Methods       Mouse embryonic fibroblasts (MEF) were cultured and treated with TNF-α or TNF-α plus pyrrolidine dithiocarbamate (PDTC) respectively. Cell proliferation were analyzed by CCK-8 method and flow cytometry. The levels of IκBα in the cytoplasm were examined with Western blotting and immunofluorescence staining. The secretion of SDF-1α was measured through ELISA.       Results        TNF-α promoted the proliferation of MEF in a concentration-dependent manner

the result of CCK-8 showed that the absorbance in TNF-α group was significantly higher than that in TNF+PDTC group and control group（P0.05). Immunofluorescence staining showed that IκBα was mainly distributed in the cytoplasm

and fluorescent intensity of IκBα in the TNF-α group was decreased significantly when compared with control and the TNF-α+PDTC group. Western blotting indicated that the expression of IκB both in the TNF-α and TNF-α+ PDTC group was dropped to a minimum value in 30 min after treatment (3 070.0±39.0 vs 1 421.7±75.3

3 212.2±57.5 vs 1 468.2±45.8

P0.05)

then gradually increased and restored to near normal level around 4 h. The expression of IκB in TNF-α+PDTC group was significantly higher than that of TNF-α group (3 112.3±89.7 vs 2 610.4±26.9

P0.05). The secretion of SDF-1α in MEF was decreased upon the treatment of TNF-α (15.9±1.6 vs 12.7±0.6

P0.05)

TNF-α+PDTC group excerted opposite effect (23.5±3.2 vs 15.0±1.2

21.6±0.4 vs 12.7±0.6

P0.05) and improved SDF-1α secretion.        Conclusion      TNF-α influences the proliferation and secreting function of mouse embryonic fibroblasts through activating NF-κB pathway.