Fubini B, Zanetti G, Altilia S, Tiozzo R, Lison D, Saffiotti U
Dipartimento di Chimica Inorganica, Chimica Fisica e Chimica dei Materiali, Facoltà di Farmacia, Università di Torino, via Pietro Giuria 7, 10125 Turin, Italy.
Chem Res Toxicol. 1999 Aug;12(8):737-45. doi: 10.1021/tx980261a.
A fibrogenic sample of cristobalite dust, CRIS (crystalline silica of mineral origin), was heated to 1300 degrees C (CRIS-1300) to relate induced physicochemical modifications to cytotoxicity. Heating did not affect dust micromorphology and crystallinity, except for limited sintering and decreased surface area of CRIS-1300. Thermal treatments deeply affected surface properties. Electron paramagnetic resonance showed surface radicals progressively annealed by heating, mostly disappearing at >/=800 degrees C. Surface hydrophilicity or hydrophobicity, evaluated with water vapor adsorption, still showed some hydrophilic patches in CRIS-800, but CRIS-1300 was fully hydrophobic. Heating modified the biological activity of cristobalite. Cytotoxicity, tested on proliferating cells of the mouse monocyte macrophage cell line J774, showed that CRIS was cytotoxic and CRIS-800 was still cytotoxic, but CRIS-1300 was substantially inert. Cytotoxicity of CRIS to the rat lung alveolar epithelial cell line, AE6, as measured by colony forming efficiency, was greatly reduced for CRIS-800 and eliminated for CRIS-1300. The rate of lactate dehydrogenase release by rat alveolar macrophages was lowered for CRIS-800, and release was completely inactivated for CRIS-1300. The absence of surface radicals and the onset of hydrophobicity may both account for the loss of cytotoxicity upon heating. Differences observed between CRIS-800 and CRIS-1300, both fully deprived of surface radicals, indicate that hydrophobicity is at least one of the surface properties determining the cytotoxic potential of a dust.
将方石英粉尘的致纤维化样本CRIS（矿物源结晶二氧化硅）加热至1300摄氏度（CRIS - 1300），以探究诱导产生的物理化学变化与细胞毒性之间的关系。加热并未影响粉尘的微观形态和结晶度，只是CRIS - 1300出现了有限的烧结现象且表面积减小。热处理对表面性质产生了深远影响。电子顺磁共振显示，加热使表面自由基逐渐退火，大部分自由基在≥800摄氏度时消失。通过水蒸气吸附评估的表面亲水性或疏水性表明，CRIS - 800仍有一些亲水区域，但CRIS - 1300完全疏水。加热改变了方石英的生物活性。在小鼠单核巨噬细胞系J774的增殖细胞上进行的细胞毒性测试表明，CRIS具有细胞毒性，CRIS - 800仍具有细胞毒性，但CRIS - 1300基本无活性。通过集落形成效率测定，CRIS对大鼠肺泡上皮细胞系AE6的细胞毒性在CRIS - 800时大幅降低，在CRIS - 1300时则完全消除。CRIS - 800使大鼠肺泡巨噬细胞的乳酸脱氢酶释放率降低，而CRIS - 1300则完全抑制了释放。表面自由基的缺失和疏水性的出现可能共同导致了加热后细胞毒性的丧失。在CRIS - 800和CRIS - 1300之间观察到的差异，二者均完全没有表面自由基，这表明疏水性至少是决定粉尘细胞毒性潜力的表面性质之一。
