Kamstrup O, Davis J M, Ellehauge A, Guldberg M
Rockwool International A/S, Hedehusene, Denmark.
Ann Occup Hyg. 1998 Apr;42(3):191-9. doi: 10.1016/s0003-4878(98)00019-2.
A summary is given of the biopersistence and pathology after inhalation by rats of two different Man-made Vitreous Fibres, MMVF21 (traditional stone wool) and MMVF34 (HT stone wool), and the results are discussed in relation to biopersistence measured after intra-tracheal instillation. The results are given from a short-term inhalation biopersistence study, a completed chronic inhalation study, and interim results from an on-going chronic inhalation study. In both the short-term and chronic studies, laboratory rats were exposed by nose-only inhalation to well-characterised fibre test atmospheres that had been selected to be largely rat respirable. The short-term inhalation study included groups exposed to aerosols targeted at 150 fibres longer than 20 microns per cm3. The exposure duration was 6 hours/day for 5 days, with subsequent post-exposure periods lasting up to 12 months. For lung burden analyses, interim sacrifices were performed at regular intervals. The ongoing chronic study comprises a group of rats exposed to the MMVF34 fibre at one exposure level of 30 mg/m3. The negative control group is filtered air. The exposure duration is 6 hours/day, 5 days/week for 2 years, with a subsequent post-exposure period lasting until approximately 20% survival in the test fibre group. Interim sacrifices are performed at months 3, 6, 12, 18 and 24 and biopersistence monitored for rats exposed for 3 and 12 months, with subsequent post-exposure periods lasting 6 months. Effectively the main protocol for the previously conducted chronic study was the same, except that there were 3 fibre exposure groups (3, 16 and 30 mg/m3) and no specific biopersistence satellite groups were included. For MMVF34, the inhalation tests of different duration show a similar biopersistence pattern, while the intra-tracheal test gives longer elimination half-times especially for long fibres. The MMVF34 fibre is considerably less biopersistent than the traditional MMVF21 fibre when comparing the calculated elimination half-times after short-term inhalation. When comparing the pathology after 3, 6, 12 and 18 months exposure, MMVF34 showed minor histopathological changes compared to MMVF21. The carcinogenicity and toxicity results of the chronic study with MMVF21 suggest that this fibre does not pose a significant health risk to humans and the current results with MMVF34 indicate that this fibre consequently should pose an even smaller risk, if any.
本文总结了大鼠吸入两种不同人造玻璃纤维（MMVF21，传统石棉；MMVF34，高温石棉）后的生物持久性和病理学情况，并结合气管内注入后的生物持久性测量结果进行了讨论。结果来自一项短期吸入生物持久性研究、一项已完成的慢性吸入研究以及一项正在进行的慢性吸入研究的中期结果。在短期和慢性研究中，实验大鼠均通过仅经鼻吸入的方式暴露于特征明确的纤维测试环境中，这些环境被选定为大鼠可吸入的。短期吸入研究包括暴露于每立方厘米含150根长度超过20微米纤维的气溶胶中的组。暴露持续时间为每天6小时，共5天，随后的暴露后观察期长达12个月。为进行肺负荷分析，定期进行中期处死。正在进行的慢性研究包括一组大鼠，以30毫克/立方米的一个暴露水平暴露于MMVF34纤维。阴性对照组为过滤空气。暴露持续时间为每天6小时，每周5天，共2年，随后的暴露后观察期持续至测试纤维组约20%的存活率。在第3、6、12、18和24个月进行中期处死，并对暴露3个月和12个月的大鼠监测生物持久性，随后的暴露后观察期持续6个月。实际上，之前进行的慢性研究的主要方案相同，只是有3个纤维暴露组（3、16和30毫克/立方米），且未包括特定的生物持久性卫星组。对于MMVF34，不同持续时间的吸入测试显示出相似的生物持久性模式，而气管内测试给出的消除半衰期更长，尤其是对于长纤维。在比较短期吸入后的计算消除半衰期时，MMVF34纤维的生物持久性明显低于传统的MMVF21纤维。在比较暴露3、6、12和18个月后的病理学情况时，与MMVF21相比MMVF34显示出轻微的组织病理学变化。MMVF21慢性研究中的致癌性和毒性结果表明，这种纤维对人类不构成重大健康风险，目前MMVF34的结果表明，如果有风险的话，这种纤维的风险应该更小。
