Enwonwu C O, Ilupeju F, Warren R C
Center for Nutrition, Meharry Medical College, Nashville, Tenn.
Caries Res. 1994;28(2):99-105. doi: 10.1159/000261629.
Salivary glands and their secretions play key roles in the prevention of dental diseases. The antibacterial and physicochemical properties of saliva are compromised in chronic malnutrition. The present study has examined the possibility that some malnutrition-induced changes in salivary gland function are potentially capable of promoting growth and metabolic activities of pathogenic oral microorganisms. Compared to well-fed controls, rats fed a 3% protein diet for 18 days showed a significant reduction (p < 0.001) in the submandibular gland arginase (L-arginine amidinohydrolase, EC 3.5.3.1) activity. Associated with the latter finding was a marked increase (+85%) in the glandular level of free arginine, this basic amino acid accounting for 12.2% of the total essential amino acids as compared with a figure of only 4.6% for the controls. The total free amino acid pool in whole saliva was relatively unaffected by malnutrition, but the levels of the basic amino acids arginine and histidine were marginally increased. Many oral bacterial species, some of which are dominant plaque microorganisms, utilize the arginine deiminase (EC 3.5.3.6) pathway. Thus, increased availability of free arginine from salivary glands offers a plausible explanation for the frequently reported observation of differential overgrowth of several potentially pathogenic microorganisms including some mutants streptococci in protein-deficient laboratory animals and may well apply to similar findings in malnourished populations in Third World countries.
唾液腺及其分泌物在预防牙科疾病中起着关键作用。慢性营养不良会损害唾液的抗菌和物理化学特性。本研究探讨了营养不良引起的唾液腺功能某些变化可能促进口腔致病微生物生长和代谢活动的可能性。与喂养良好的对照组相比，喂食3%蛋白质饮食18天的大鼠下颌下腺精氨酸酶（L-精氨酸脒基水解酶，EC 3.5.3.1）活性显著降低（p < 0.001）。与后一发现相关的是游离精氨酸的腺体水平显著增加（+85%），这种碱性氨基酸占必需氨基酸总量的12.2%，而对照组仅为4.6%。全唾液中的总游离氨基酸池相对不受营养不良的影响，但碱性氨基酸精氨酸和组氨酸的水平略有增加。许多口腔细菌种类，其中一些是菌斑中的优势微生物，利用精氨酸脱亚氨酶（EC 3.5.3.6）途径。因此，唾液腺中游离精氨酸可用性的增加为经常报道的在蛋白质缺乏的实验动物中几种潜在致病微生物（包括一些突变链球菌）过度生长差异的观察结果提供了一个合理的解释，并且很可能适用于第三世界国家营养不良人群的类似发现。
