The KEGG analysis showed that the downregulated genes at day 3 Cracr2b, Nr4a1, Fos, Jun, Vegfa were involved in the MAPK signalling pathway, Nr4a1, Fos, Jun were involved in the relaxin signalling pathway, chemical carcinogenesis-receptor activation, and rheumatoid arthritis. The gene discussed is FOS; the disease is rheumatoid arthritis.