TNF and rheumatoid arthritis: To further verify the expression of LOXL1 in rheumatoid arthritis synovium, we used TNF-α to stimulate human osteosarcoma synovial cells for 48 h, extracted total protein and total mRNA, and detected the expression of LOXL1, INOS, COX2, and IL-6 in them through RT-qPCR and western blot.