報告書番号

U89036

タイトル（和文）

石炭灰と二酸化窒素の複合暴露による生体反応３．ゴールデンハムスター呼吸器の形態学的変化

タイトル（英文）

BIOLOGICAL EFFECTO OF COMBINED EXPOSURE TO COAL FLY ASH AND NITROGEN DIOXIDE 3.MORPHDOGICAL CHANGGES IN RESPIRATORYORGANS OF GOLES IN RESPIRATORY ORGANS OF GOLDEN HAMSTER

概要 （図表や脚注は「報告書全文」に掲載しております）

本研究は，石炭灰とガス状汚染物質である二酸化窒素（ＮＯ２）との複合暴露がゴールデンハムスターの呼吸器系組織に及ぼす形態学的変化を明らかにする目的で行い，以下の結果を得た。１．気道および肺胞上皮細胞の変化は主にＮＯ２によるもので，石炭灰とＮＯ２との複合暴露による相乗的な影響は認められなかった。２．肺胞マクロファージ（ＡＭ）への影響は暴露期間によって異なり，ＮＯ２が４ｐｐｍの場合の短期複合暴露では，ＡＭの肺胞内滞留時間が短縮するため，石炭灰の体外排出が促進された。しかし，暴露が長期に及ぶと，ＮＯ２暴露による気道の病理学的変化とＡＭの活性の低下が起こるため，ＡＭの集積形成が石炭灰単独暴露群に比べて，より早く起こることが推察された。３．しかし，ＮＯ２が０．４ｐｐｍの場合には，ＮＯ２によるＡＭと気道上皮細胞への影響はほとんどみられなかった。以上のゴールデンハムスターを用いた複合暴露実験の

概要 （英文）

MALE GOLDEN HAMSTERS WERE EXPOSED TO 2 MG/QUBE M OF COAL FLY ASH(FA)AND/OR NITROGEN DIOXIDE(NO2)TO INVESTIGATE THE MORPHOLOGICAL CHANGES IN RESPIRATORY ORGANS. LOSS OF CILIA AND HYPERTROPHY OF NON-CILIATED CELLS IN RESPIRATORY TRACTS OCCURRED IN THE NO2-EXPOSED GROUP (NO2-GROUP)AND COMBINED EXPOSURE TO BOTH FA AND NO2 GROP (NF-GROUP).THESE CHANGES BECAME SEVERER WITH INCREASING NO2 CONCENTRATION.WITH SHORT-TERM EXPOSURE TO 2 MG/QUBE M OF FA AND /OR 3.5 PPM OF NO2,THE NUMBERS OF ALVEOLAR MACROPHAGES (AMS) IN ALVEOLI INCREASED EXCEPT FOR THE CONTROL GROUP. THE DIAMETER OF AMS IN THE NO2-AND NF-GROUP WAS SMALLER THAN THAT OF AMS IN THE CONTROL AND FA-GROUP. THE RATIO OF PARTICLE-LADEN AMS TO TOTAL AMS IN THE NF-GROUP WAS LOWER THAN THAT IN THE FA-GROUP. THESE RESULTS SUGGEST THAT SHORT-TERM EXPOSURE TO FA AND 3.5PPMNO2 MIGHT ACCELERATE LUNG CLEARANCE OF INHALED FA PARTICLES. AFTER LONG-TERM EXPOSURE TO 4.0 PPM NO2 AND/OR FA,PARTICLE-LADEN AMS IN ALVEOLI CLUSTERED MORE FREQUENTLY IN THE NF-GROUP THAN IN THE FA-GROUP. THIS SUGGESTS THAT LONG-TERM EXPOSURE TO FA AND 4.0 PPM NO2 DAMAGED AMS AND AIRWAY EPITHELIAL CELLS,AND THAT PARTICLE-LADEN AMS ACCUMULATED MORE THANIN THE FA-GROUP. ON THE OTHER HAND,AFTER LONG-TERM EXPOSURE TO BOTH 0.4PPM OF NO2 AND 2 MG/QUBE M OF FA,RESPIRATORY TRACTS SHOWED FEW PATHOLOGICAL CHANGE AND ACCUMULATIONS OF AMS WERE NOT DIFFERENT FROM THOSE IN THE FA-GROUP. FROM THESE RESULTS,CURRENT AMBIENT LEVEL OF NO2 MAY NOT AFFECT THE MORPHOLOGICAL CHANGES DUE TO FA INHALATION.

報告者

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