Abstract: BACKGROUND ＆ AIM: To study the DNA damage effect of formaldehyde to mouse testicular cell in vivo and in vitro. MATERIAL AND METHODS: Mice testicular cell was exposed to 6 ,30 ,60 ,120 μmol/L dose of formaldehye in vitro, and to 0.2 ,2, 20 mg/kg dose of formaldehyde five days by intraperitoneal injection.The single cell gel electrophoresis was used to detect the DNA damage. RESULTS :In vitro the DNA migration in group of 6 μmol/L dose obviously showed the significant damage to testicular cell DNA.30 μmol/L group have the most pronounced. But the damaging effect when dose increased, DNA migration decreased by contraries . In the highest dose group (120 μmol/L) there was no significance effect comparing to the concurrent negative control (P>0.05).In vivo the 0.2 and 2 mg/kg groups had the statisticsignificance against the concurrent control (P<0.01 ),especially the 0.2 mg/kg group . CONCLUSION: Formaldehyde is genotoxic to mouse testicular cell . DNA strand break is the primary DNA damage in low dose.

Key words: single cell gel electrophoresis, formaldehyde, DNA damage, spermary