〔Abstract〕 Objective To explore the expressions of TSP-1 in the gingiva tissues of rat periodontitis model, and to verify the effect of TSP-1 on the expressions of interleukin-6(IL-6) and cyclooxygenase-2(COX-2) in primary cultured human periodontal ligament fibroblasts(hPDLFs). Methods 12 female SD rats were randomized into 2 groups, periodontitis group(ligature induced,n=6), control group(left unligated,n=6). Western blot was used to detect the protein level of TSP-1, and qRT-PCR was used to detect the mRNA level of TSP-1, IL-6 and COX-2 in the gingiva tissues in each group. After primary culturing hPDLFs with tissue block method, recombinant adenovirus(Ad-TSP-1-GFP) carrying TSP-1 gene was constructed and cells were transfected with no-load adenovirus(Ad-GFP) as a negative control, or add recombinant tsp-1 protein(rtsp-1) to the supernatant of hPDLFs culture. Il-6 expression level of hPDLFs was detected by ELISA. The expression of COX-2 in hPDLFs was detected by Western blot. mRNA expression levels of IL-6 and COX-2 were detected by qRT-PCR. Results Compared to the normal group, TSP-1 expressions in gingiva tissues were markedly increased in periodontitis group, and mRNA levels of IL-6 and COX-2 were synchronously elevated. Compared with Ad-GFP group, the level of TSP-1 was significantly higher in Ad-TSP-1-GFP group, meantime, the expression of IL-6 and COX-2 at both protein and mRNA levels in Ad-TSP-1-GFP group were also promoted.The results were confirmed by adding rTSP-1 into cell culture, since the Western blot and qRT-PCR analyses revealved a prominent upregulation of IL-6 and COX-2 after being induced by rTSP-1. Conclusion TSP-1 can significantly upregulate the expressions of IL-6 and COX-2 in hPDLFs, and then aggravate the symptoms of periodontitis.