Lekholm U, Wallenius K
Odontol Revy. 1976;27(1):11-8.
Though previous experiments with fat-soluble carcinogens have demonstrated a protective effect of the saliva against chemically induced oral cancer it is not known if this also holds true for water-soluble carcinogenic agents. In vitro experiments indicate that the water-soluble 4NQO (4-nitrochinoline N-oxide) easily penetrates a layer of saliva similar with that normally present on the oral mucous membranes. It is possible that this quality, on intraoral applications of 4NQO, could eliminate the protective barrier of saliva. The protective effect of the saliva was examined in the present investigation. Xerostomia was induced in 15 rats and 4NQO was applied to the palate 3 times a week. After 4.7 months, on an average, palatal cancer appeared in all rats. In comparable investigations the result was 7 months with rats treated in an identical manner except for their salivary secretion remaining intact. This time difference represents approximately 33% of the time necessary for the development of oral cancer in normal rats by means of 4NQO. It was concluded, that a protective effect of the saliva exists whether the oral mucous membranes are attacked by water--or fat-soluble carcinogens.
尽管先前对脂溶性致癌物的实验已证明唾液对化学诱导的口腔癌具有保护作用，但对于水溶性致癌剂而言，情况是否如此尚不清楚。体外实验表明，水溶性的4NQO（4-硝基喹啉-N-氧化物）能够轻易穿透一层类似于正常存在于口腔黏膜上的唾液层。在口腔内应用4NQO时，这种特性有可能消除唾液的保护屏障。本研究对唾液的保护作用进行了检测。给15只大鼠造成口干症，每周3次将4NQO涂抹于腭部。平均4.7个月后，所有大鼠均出现腭部癌症。在可比研究中，除唾液分泌保持正常外，以相同方式处理的大鼠出现腭部癌症的时间为7个月。这一时间差异约占正常大鼠通过4NQO诱发口腔癌所需时间的33%。得出的结论是，无论口腔黏膜受到水溶性还是脂溶性致癌物的攻击，唾液均具有保护作用。
