Mechanisms For Metabolic Disorder Of Asymmetric Dimethylarginine In Human Umbilical Vein Endothelial Cells Induced By Formaldehyde

To observe the characters of asymmetric dimethylarginine (ADMA)metabolism and investigate possible mechanisms of Human Umbilical VeinEndothelial Cells (HUVEC-12) damaged by formaldehyde through evaluating thedegree of injuried from oxidative and crosslink.damage.Methods: HUVEC-12 were cultured in Dulbecco's Modified Eagle's Medium(DMEM) containing 10% fetal bovine serum (FBS) and 37℃, 5%CO₂ for 24 hours.Cells were treated with formaldehyde (concentration as 6.25, 12.5, 25, 50, 100, 200,400μmol·L^-1 respectively) for experimental groups and equivalence PBS for controlgroup. The degree of endothelial cells injury was evaluated by measurement of lactatedehydrogenase (LDH) release, content of malondialdehyde (MDA) in conditionedmedium; the activity of total superoxide dismutase (T-SOD) and endothelial nitricoxide synthase (eNOS), the content of glutathione (GSH) in cells were measured bykits respectively. The concentration of ADMA and the activity ofdimethylaminohydrolase (DDAHâ…¡) were assayed by high performance liquidchromatography (HPLC). The percent of DPC in cells were assayed by usingKCL-SDS method.Results:1. Treatment with formaldehyde at the higher level (50.00～400.00μmol·L^-1) for 24hours significantly increased the release of LDH in the conditioned medium(p＜0.05). On the contrary, formaldehyde at lower level (6.25～25.00μmol·L^-1)significantly decreased the release of LDH (P＜0.05).2. Formaldehyde (6.25～400.00μmol·L^-1) significantly increased the content of MDAin the conditioned medium (P＜0.05). The content of GSH and the activity of T-SOD in cells are significantly decreased at the higher lever(12.50～400.00μmol'L^-1) of formaldehyde (P＜0.05).3. Treatment with formaldehyde increased the concentration of ADMA in theconditioned medium and decreased the activity of DDAHâ…¡in the cells (P＜0.05).Formaldehyde at the lower lever significantly promoted activity of eNOS in cells(P＜0.05). At the higher lever (＞12.50μmol·L^-1) formaldehyde significantlyinhibited the activity of eNOS in cells (P＜0.05).4. Formaldehyde at the high lever significantly increased the rate of DNA-Proteincrosslink in cells (P＜0.05).Conclusions:1. Formaldehyde induced aggregation of ADMA in Human Umbilical VeinEndothelial Cells.2. Disorder metabolism of ADMA induced by formaldehyde may be related torestrain activity of DDAHâ…¡by oxidative damage and DNA-Protein crosslinks.