COLLABORATIVE WORK TO EVALUATE TOXICITY ON MALE REPRODUCTIVE ORGANS BY REPEATED DOSE STUDIES IN RATS : 23)A COMPARATIVE 2-AND 4-WEEK REPEATED ORAL DOSE TESTICULAR TOXICITY STUDY OF BORICACID IN RATS
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概要
- 論文の詳細を見る
To assess the validity and limitations of 2-week repeated daily dosing to detect toxic effects on male reproductive organs in rodents, a comparative 2- and 4-week oral repeated dosing study of boric acid, a known testicular toxicant, was given to 6- or 8-week-old Crj:Wistar rats at daily levels of 0, l25, 250 and 500 mg/kg. The ages of the rats were selected so that they were all sacrificed at 10 weeks of age. The testes and epididymides were weighed at necropsy; histopathological specimens were prep(ared in a routine manner and stained with H&E or PAS-H. In addition, the sperm number and motility rates were evaluated. There were no boric acid-induced effects on reproductive organ weights and on gross behavior/appearance in any groups in either the 2- or 4-week studies. The sperm number and motility rate were not decreased in any group after 2 weeks, while both decreased in the 250 and 500 mg/kg groups after 4 weeks. Histopathologically, as evidence of toxicity at the early stage of boric acid exposure, retention of step l9 spermatids of stages IX - XI was observed in the testes of almost all rats treated with 500 mg/kg after both 2 weeks and 4 weeks. Degenerative/necrotic germ cells and multinucleated giant cell formation were observed in 2 weeks, though to a lesser extent than in 4 weeks. On stage analysis of germinal cells in 2 weeks, spermatogonia and spermatids of stage VII were found to be decreased, and pachytene spermatocytes of stage X were increased. In conclusion, the results indicate that if the selection of doses is appropriate, testicular toxicity of boric acid can be detected even after only 2 weeks of repeated daily oral treatment.
- 日本トキシコロジー学会の論文
- 2000-10-25
著者
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Nakao Maiko
Research Center Kyorin Pharmaceutical Co. Ltd.
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Nakao Maiko
杏林製薬研究センター
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Kudo Satoshi
Research Center, Kyorin Pharmaceutical Co., Ltd.
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Kudo Satoshi
Research Center Kyorin Pharmaceutical Co. Ltd.
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TANASE Hirofumi
Research Center, Kyorin Pharmaceutical Co., Ltd.
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MIYATA Yuki
Research Center, Kyorin Pharmaceutical Co., Ltd.
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YAMASAKI Masakazu
Research Center, Kyorin Pharmaceutical Co., Ltd.
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TSURU Kiyoyuki
Research Center, Kyorin Pharmaceutical Co., Ltd.
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IMAI Shigeru
Research Center, Kyorin Pharmaceutical Co., Ltd.
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Miyata Yuki
Res. Center Kyorin Pharmaceutical Co. Ltd.
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Miyata Yuki
Research Center Kyorin Pharmaceutical Co. Ltd.
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Tanase Hirofumi
Research Center Kyorin Pharmaceutical Co. Ltd.
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Yamasaki Masakazu
Research Center Kyorin Pharmaceutical Co. Ltd.
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Imai Shigeru
Research Center Kyorin Pharmaceutical Co. Ltd.
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Tsuru Kiyoyuki
Research Center Kyorin Pharmaceutical Co. Ltd.
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Tsuru Kiyoyuki
Kyorin Pharmaceutical Co. Ltd. Research Center
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Kudo Satoshi
Res. Center Kyorin Pharmaceutical Co. Ltd.
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Tanase Hisao
Research Center Kyorin Pharmaceutical Co. Ltd.
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