We also firstly generated SD rats with Cre-LoxP-mediated conditional knockout of TREX1 (TREX1Cre+/-rats) and revealed that DNA fragments promoted proinflammatory cytokine release and T-cell activation in AIA rats when the DNA-metabolizing enzyme TREX1 was deleted, which is in line with in vitro studies showing that knockdown of TREX1 promoted the release of proinflammatory cytokines in RA-FLSs challenged with DNA fragments. The gene discussed is TREX1; the disease is rheumatoid arthritis.