Nicotine (CAS No. 54-11-5) and Isoflurane were purchased from Baxter Healthcare (Deerfield, IL, USA). Safranin-O (CAS no. 477-73-6) and fast green (CAS no. 2353-45-9) were obtained from Hengyuan Biotech (Shanghai, China). RIPA lysis buffer and BCA Protein Assay kit were purchased from Beyotime Institute of Biotechnology (Haimen, China). TRIzol reagent kits were obtained from Omega Bio-Tek (Doraville, GA, USA). Reverse transcription and quantitative PCR (qPCR) kits were purchased from TaKaRa Biotechnology Oligonucleotide primers for analyzed genes were synthesized by Sangon Biotech (Shanghai, China). The nucleus and cytoplasm extraction kit was purchased from Applygen Technologies Inc (Beijing, China). Pyruvate was purchased from Gibco (St. Louis, MO, USA). H3K9, H3K14, and IgG antibodies were obtained from Abcam (Cambridge, UK). DNA purification kit was purchased from Tiangen (Beijing, China). DMEM/F12 (1:1) and fetal bovine serum were supplied by Gibco. Polyclonal antibodies for Col2A1, ACAN, HDAC1, HDAC2, and Snail were purchased from Santa Cruz Biotechnology (Santa Cruz, CA, USA). si-Snail was purchased from Gene Pharma (Shanghai, China). Lipofectamine 2000 Reagent was obtained from Invitrogen (CA, USA). Penicillin was purchased from Harbin pharmaceutical Co. Ltd (Harbin, China). The remaining chemicals and