報告書番号

U89018

タイトル（和文）

石炭灰と二酸化窒素の複合影響による生体反応 -Ⅱ 肺の代謝活性への影響-

タイトル（英文）

Biological effects of combined exposure to coal fly ash and nitrogen dioxide -II. Effects on metabolic activities in the lung-

概要 （図表や脚注は「報告書全文」に掲載しております）

石炭灰（FA）の健康影響評価を目的に、実験動物に対する二酸化窒素（NO2）との複合吸入実験を実施している。FA単独の長期暴露や、FAとNO2の複合暴露に於ける肺の生化学的な変化を明らかにする目的で、対照・NO2単独・FA単独・複合暴露の4群を設け、2 mg/m3のFAに、4または0.4 ppmのNO2をそれぞれ90・180日間、ゴールデンハムスターに複合暴露した。その結果、FA単独群では暴露60日目以降に抗酸化活性の低下がみられ、180日目に過酸化脂質が増加した。複合暴露群では暴露の初期にはNO2主体の影響が現れたが、長期暴露後には石炭灰主体の影響がみられ、経時的変化にふたつの相が認められた。また、NO2濃度が4 ppmの場合には、両単独暴露群と有意差のある変化が抗酸化活性の一部に認められたものの、0.4 ppmの場合には暴露期間を通して両単独群と統計的に有意差のある変化はなく、FAとNO2の複合した影響は認められなかった。

概要 （英文）

Golden hamsters were exposed to 2 mg/m3 of coal fly ash (FA) and/or 4 ppm nitrogen dioxide (NO2) for 90 days or 2 mg/m3 FA and/or 0.4 ppm NO2 for 180 days to clarify the biochemical changes in the lungs. Changes in amounts of lipid peroxide (TBA value) and antioxidative factor (NPSH), antioxidative enzyme activities (GPx, G6PDH), energy-generating enzyme activities (PK, SCR), collagen content (HOP) and collagen metabolizing enzyme activity (PZP) were examined. In 4 ppm NO2 alone-exposed group, TBA value increased at the early phase of exposure and then decreased to corresponding control level. In 0.4 ppm NO2 alone-exposed group, the value increased only at 180 days after the exposure. Amount of NPSH in the 4 ppm NO2 exposed group kept higher value compared to the control group throughout the exposure. Specific activities of G6PDH, GPx, PK, SCR and PZP increased at the beginning of the exposure but decreased to control level at 60-day. In the 0.4 ppm NO2 group, NPSH increased at 180-day of exposure, but other metabolic activities showed little change throughout the exposure. The obtained results were similar to those reported by other investigators using other small laboratory animals. In FA alone exposed group, no changes were observed until 60-day of exposure, but both TBA value and the amount of NPSH increased at 180-day. G6PDH activity elevated from the beginning to the end of exposure period. PK activity in FA exposed group was the same as the control group. SCR and PZP activities decreased after 90-day exposure and GPx activity decreased markedly after 60-day exposure. Combined exposure group showed two different phases along with the exposure time course. At the initial 30-day of exposure, changes were similar to those occurred in NO2 alone-exposed group. Changes after 60-day of exposure were similar to those obtained in FA alone-exposed group. FA alone exposed group showed some changes related to lipid peroxidation. Low concentration, long term FA exposure should be conducted to clarify the mechanism of lipid peroxidation in the exposed lung.

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