Stich H F, Stich W, Rosin M P, Vallejera M O
Int J Cancer. 1984 Dec 15;34(6):745-50. doi: 10.1002/ijc.2910340602.
The frequency of exfoliated cells with micronuclei in buccal swabs was used to estimate the protective effect of vitamin A, beta-carotene and canthaxanthin (4,4'-diketo-beta-carotene) on the buccal mucosa of betel (areca) nut/tobacco chewers. Micronuclei were scored on exfoliated cells taken by swabbing and stained with the Feulgen reaction and fast green. The betel (areca) nut/tobacco chewers served as their own controls. Prior to the administration of vitamin A and beta-carotene, the examined betel quid chewers had elevated frequencies of micronucleated buccal mucosa cells, averaging 4.03% +/- 1.24 SD (n = 26) and 3.43% +/- 1.22 SD (n = 25), respectively. The frequency of micronucleated buccal mucosa cells in non-chewers and non-smokers was 0.51% (n = 52). Following a 9-week ingestion of vitamin A (150,000 IU/week) and beta-carotene (180 mg/week in 6 capsules), the frequency of micronucleated cells decreased significantly (p less than 0.001) to 1.70% and 1.16%, respectively. No significant shift in the frequencies of micronucleated cells was observed following the intake of canthaxanthin (180 mg/week in 6 capsules) for 9 weeks or that of a placebo. The lack of protective activity of canthaxanthin, which is a good trapper of oxygen singlets but cannot be converted into vitamin A, suggests that vitamin A and beta-carotene exert their inhibitory effect on the formation of micronuclei by a mechanism not involving the scavenging of free radicals. The efficacy of beta-carotene as an inhibitor of micronucleated cell formation, the lack of toxicity, and its availability from a multitude of dietary sources should focus attention on this carotenoid as a promising chemopreventive agent.
用颊拭子中含微核的脱落细胞频率来评估维生素A、β-胡萝卜素和角黄素（4,4'-二酮-β-胡萝卜素）对嚼槟榔/烟草者颊黏膜的保护作用。微核在通过擦拭获取并用福尔根反应和固绿染色的脱落细胞上进行计数。嚼槟榔/烟草者以自身作为对照。在给予维生素A和β-胡萝卜素之前，所检查的嚼槟榔者颊黏膜细胞微核频率升高，分别平均为4.03%±1.24标准差（n = 26）和3.43%±1.22标准差（n = 25）。非咀嚼者和非吸烟者颊黏膜细胞微核频率为0.51%（n = 52）。在摄入维生素A（150,000国际单位/周）和β-胡萝卜素（180毫克/周，分6粒胶囊服用）9周后，微核细胞频率显著降低（p＜0.001），分别降至1.70%和1.16%。在摄入角黄素（180毫克/周，分6粒胶囊服用）9周或服用安慰剂后，未观察到微核细胞频率有显著变化。角黄素是单线态氧的良好捕获剂但不能转化为维生素A，其缺乏保护活性表明维生素A和β-胡萝卜素通过不涉及清除自由基的机制对微核形成发挥抑制作用。β-胡萝卜素作为微核细胞形成抑制剂的功效、无毒性以及可从多种饮食来源获取，应使人们将注意力集中在这种类胡萝卜素上，将其视为一种有前景的化学预防剂。
