Laboratory tests of in-patients seriously affected by photochemical smog developing in Osaka Prefecture in August 1971 revealed such abnormal findings as increased white blood cell (WBC) count, elevated leucoindex (the ratio of neutrophilic leucocytes to lymphocytes) and elevated serum alkaline phosphatase activity.
In connection with the foregoing findings there are reports in the literature regarding experimental animal exposed to ozone (O3) alone. The authors therefore exposed mice (JCL-ICR, _??_) to low concentrations of photochemical oxidants (Ox) for a short term to elucidate the effect of Ox under actual conditions. Oxidants were photochemically synthesized in a smog chamber by UV-irradiation of gases containing automobile exhaust gas, nitric oxide and propylene. The results obtained in this study were compared with those of exposure to O3 alone which is one of the main components of Ox. In addition, the influence of high temperature environment and exercise considered to enhance the effects of photochemical smog was alsoexamined as well as the effects of administration of neurotropic agents such as adrenaline, atropine and pilocarpine. The following results were obtained.
1) WBC count in mice was significantly increased after exposure to Ox at average concentration of 0.37 0.58 ppm and O3 at concentration of 3-5 ppm for 3 hours. In these mice exposed to O3, red blood cell count, total hemoglobin content and hematocrit value were also increased, but no change was observed in the mean corpuscular constants of red blood cells.
2) Leucoindex was significantly elevated after exposure to Ox at average concentration of 0.35 ppm and O3 at concentration of 2 ppm for 3 hours. A dose-effect relationship could be observed between leucoindex and gas concentration but not between WBC count and gas concentration. The finding that the lowest effective concentration of Ox was lower than that of O3 suggested that components other than O3 contained in Ox enhanced the effect of O3. Furthermore, leucoindex appeared to be a more sensitive indicator of the effects of Ox than WBC conunt, because there were a number of mice which showed only elevated leucoindex without any increase of WBC count.
3) Increase of leucocyte count and elevation of leucoindex after exposure to Ox were remarkably enhanced by administration of adrenaline prior to exposure but not by administration of atropine or pilocarpine. These findings suggested that the sensitivity to Ox might be influenced by disorders of the autonomic nervous system often observed in in-patients.
4) Increase of WBC count and elevation of leucoindex were not enhanced by exposure to Ox containing methylnitrate additionally.
5) WBC count decreased after compulsory exercise in a motor driven wheel or exposure to high temperature (35°C) environment. This is a change opposite to that when exposed to Ox and O3.Therefore, elevated WBC count as the indicator of effect of Ox and O3 could not be used for the elucidation of synergetic effect of exercise or high temperature.
6) Both the basic type and the magnesium activated type of alkaline phosphatase in the serum of mice exposed to Ox at average concentration of 0.34 ppm and O3 at concentration of 3 ppm for 3 hours showed decreased activities.
