報告書番号

U97078

タイトル（和文）

実験小動物における５０Ｈｚ回転磁界の生殖への影響

タイトル（英文）

EFFECTS OF ROTATING 50HZ MAGNETIC FIELDS ON REPRODUCTION AND FETAL DEVELOPMENT IN SMALL LABORATORY ANIMALS

概要 （図表や脚注は「報告書全文」に掲載しております）

商用周波磁界の生殖，特に胎児の脂肪と奇形発生への影響を検討するため，ゴールデンハムスターを用いて器官形成期と交配前から妊娠期までの曝露実験を行った。器官形成期と交配前から妊娠期への第１回目の実験では０，７０ミューＴｒｍｓの５０Ｈｚ回転円磁界を，第２回目の交配前から妊娠期への実験では０，７，７０，３５０ミューＴｒｍｓの５０Ｈｚ回転円磁界を曝露した。器官形成期への曝露実験では，主に胎児の外表異常，内臓の異常発生に着目して検査したが２回の実験とも異常の発生■度に対照群と曝露群の差はみられなかった。交配前から妊娠期への曝露実験では，主に胚・胎児の死亡や胎児の奇形発生に着目して検査したが，これらの項目や発生■度に各曝露群と対照群との差はみられなかった。ゴールデンハムスターを用いての上記や受託研究でのラットの実験結果から，３５０ミューＴｒｍｓまでの５０Ｈｚ回転円磁界の曝露は，実験動物の胎児の死亡や外表・内臓骨格の奇形の発生■度に影響を与えないことが示された。

概要 （英文）

THE OBJECTIVE OF THIS STUDY WAS TO CLARIFY THE POSSIBLE HEALTH EFFECTS OF EXPOSURE TO POWER-FREQUENCY MAGNETIC FIELDS (MF) ON MATERNAL REPRODUCTIVE FUNCTIONS,EMBRYO AND/OR FETAL DEATH AND MALFORMATION,IN GOLDEN HAMSTERS. IN THE FIRST EXPERIMENT,PREGNANT HAMSTERS WERE EXPOSED TO 0 (SHAM) OF 70 MU TRMS CIRCULARLY POLARIZED 50-HZMF FROM 6 TO 13 DAY OF GESTATION. IN THE SECOND EXPERIMENT,MALE AND FEMALE HAMSTERS WERE EXPOSED TO 0 OR 70 MU TRMS IN THE FIRST RUN,AND TO 0,7,70,350 MU TRMS CIRCULARLY POLARIZED 50-HZ MF FIELDS FOR 6 WEEKS BEFORE MATING IN THE SECOND RUN. THEN,PREGNANT ANIMALS WERE CONTINUOUSLY EXPOSED TO MF DURING PREGNANCY. 1.FIRST EXPERIMENT:IN THE TWO RUNS,NO INTER-GROUP DIFFERENCES WERE OBSERVED IN THE BODY WEIGHT AND GENERAL HEALTH OF MATERNAL ANIMALS. DEATH RATES OF EMBRYOS AND FETUSES,NUMBERS OF VIABLE FETUSES,BODY WEIGHT AND SEX RATIO OF VIABLE FETUSES SHOWED NO DIFFERENCE BETWEEN THE GROUPS. EXTERNAL AND VISCERAL ABNORMALITIES IN EXPOSED FETUSES WERE NOT SIGNIFICANTLY DIFFERENT FROM THE SHAM GROUP. 2.SECOND EXPERMENT:MOST OF THE EXAMINED ENDPOINTS FOR THE MATERNAL ANIMALS DID NOT SHOW ANY SIGNIFICANT DIFFERENCES BETWEEN THE EXPOSED AND SHAM GROUP IN THE FIRST RUN. THE FERTILITY INDEX WAS VARIABLE IN THE TWO RUNS,BUT WAS WITHIN THE NORMAL RANGE FOR THIS SPECIES. ALL ENDPOINTS INDICATING FETUS DEVELOPMENT AND THE INCIDENCE OF MALFORMATION SHOWED NO STATISTICAL DIFFERENCES BETWEEN GROUPS IN BOTH THE FIRST AND SECOND RUN. BASED ON BOTH THESE RESULTS FROM REPLICATED EXPERIMENTS,AND RAT STUDIES (DATA NOT SHOWN),IT IS CONCLUDED THAT EXPOSURE TO POWER-FREQUENCY MAGNETICFIELDS AT UP TO 350 MU TRMS DURING SPERMATOGENESIS (6 WEEKS) AND FETALORGANOGENESIS DID NOT AFFECT REPRODUCTION AND FETAL TERATOGENESIS IN GOLDEN HAMSTERS.

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