The nose as a sentinel of exposure to air pollutants single cell gel electrophoresis (SCGE) assay in nasal cells of adults exposed to three different atmospheric conditions in southwest metropolitan mexico city (SWMMC)

The Single Cell Gal Electrophoresis (SCGE) Assay (Exp Cell Res 175:184, 1988, Singh NP et al)detects DNA strand breaks that can be used as a biomarker of oxidant exposure and as an indicator of the carcinogenicity and mutagenicity of a substance. Exposure to a polluted urban atmosphere induces DNA nasal SSBś (EHP 104:160, 1996,Calderón-Garcidueñas L.,et al).The SCGE assay using fresh nasal cells was done in three groups of healthy, well-nourished,non-smoking SWMMC adult residents (#51), with either> 10h or< 6h daily outdoor exposures, in three Fall 1996 dates:October 15, November 5 & 13,with different pollutant concentrations in the days previous to the nasal biopsies. October 15th.,corresponded to an environrental emergency; November 5th.,to an "average" polluted period and the November 13th. sampling was done 42h after the beginning of a large fire in the Northern part of MMC that consumed 13 million liters of gasoline in 36h. The maximal nasal DMA damage (SSBś) was recorded October 15th, after high 03 concentration exposures: 4.919 ppm 03 in the week previous to the nasal biopsies with a maximal 03 peak of 0.238 ppm, p=0.0007. Moreover, adults with<6h outdoor exposures had<DNA damage than those with>10h, p=0.012 for October 15th and p= 0.001 for November 5th.However, for November 13th.,the DNA nasal damage was equally severe for all subjects,regardless of their outdoor exposures. This severe nasal damage in downwind Southwest Mexico City residents could be atributec to the inhalation of the gasoline fire fumes. The SCGE assay using fresh nasal respiratory epithelium is an excellent biomarker if oxidant exposure in adults exposed to atmospheric pollutants.