| Co-Investigator(Kenkyū-buntansha) |
HORIE Akio UOEH, School of Medicine, Dept. Pathol. Oncol., Professor, 医学部・第一病理学, 教授 (80122852)
TANAKA Isamu UOEH, Inst. Ind. Ecol. Sci., Dept. Environ. Health eng., Associate Professor, 産業生態科学研究所・労働衛生工学, 助教授 (00038035)
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| Research Abstract |
In furniture makers in Japan, various wood materials from Japan, North America and trpoical zone, have been used. No major single wood material has been specified through the interview survey in major furniture industries. Therefore, for the present animal experiment, beech was chosen, because in western countries wood dust from beech nas been considered to be one of the causal agents for nasal cancer in man and because in Jpapn beech was also used before 1960s'.
This study aims to see the carcinogenic effect of beech wood dust due to long term exposure by inhalation in rats. Fresh beech wood dust has been generated by a newly developed dust generator. 20 male Wister rats were exposed to beech wood dust for 6 horus a day, 5 days a week, for 6 months in the exposure chamber. On average, 15.1mg/m^3 of wood dust per day with 7.4 <micrn>m diameter of a particle of wood dust were exposed. Non-exposed 20 male Wister rats as a control group were fed in an adjacent chamber. One year after the exposure, exposed and non-exposed rats were decapitated and head including nasal cavity and sinus, lung, liver, kidney, spleen and pancreas were removed from each rat and examined pathologically under an optical microscope.
In the exposed rats, one malignant lymphoma in the spleen was observed. On the other hand, in the non-exposed rats, one hepatocellular carcinoma, one malignant lymphoma, one acinal cell adenoma in the pancreas have been found. No dysplasia was observed and no particles of wood dust was found in the lung among exposed rats. There was no remarkable differences in growth and weight of each organs removed between the exposed and non-exposed rats.
Although this experiment showed no carcinogenic effect among the exposed rats to beech wood dust, further experiment should be continued to clarify the carcinogenicity of wood dust.
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