齲蝕誘発性高シュクロース食がラット顎下腺の分泌機能に及ぼす影響

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Rat submandibular glands (SMG) can discriminate the nature of the stimulus and secrete three types of protein in protein in response to varios agonists under different conditions. However, no information is available on the effects of cariogenic diets on salivary secretion by the SMG. Present studies were, thus, designed to determine whether special proteins secreted by the SMG in response to three types of agonists were involved in dental caries formation. Male Sprague-Dawley rats at 21 days of age were used in each group consisting of 5 to 10 animals. Cariogenic diets (Diet 2000 and Diet 2000 adjusted sucrose concentrations to 30%) were fed for 3,4 and 7 weeks from 21 days. MF powder chows were also fed for controls. Submandibular saliva was intra-orally collected by the cannulation method for 1 h. Octopamine (OCT), isoproterenol (IPR) and oxymetazoline (OXY) were used as sialogogues. The results were as follows : 1. Dental caries incidence in molar teeth of rats fed for 3 weeks was less than for those fed for 4 weeks and caries was more spread into dentine in rats fed for 7 weeks in both experimentals. 2. By cariogenic diets body weight of experimentals was substantially reduced for 3 to 7 weeks when compared to that of controls (it was reduced in turn in Diet 2000 (30%) and Diet 2000 groups). Wet weights of the SMG per body weight increased significantly in only 56% fed for 3 and 4 weeks, whereas no change was observed between experimentals fed for 7 weeks and controls. 3. Atrophy of granular convoluted tubule cells and acinar cells was observed in the SMG of rats fed for 4 weeks, but granules in granular convoluted tubule cells in one rat were completely disappeared or in another rat markedly accumulated in experimentals. 4. Volumes of saliva secreted and flow rates in response to three types of agonists in both experimentals increased significantly except a few cases. Protein concentration in saliva of both experimentals secreted in response to OCT and IPR was significantly reduced with a few exceptions. No change in saliva in response to OXY was observed. Total amounts of protein secreted in response to OCT increased significantly with Diet 2000 fed for 7 weeks. These of saliva in response to IPR also increased significantly in both experimentals fed for 3 weeks, whereas these were significantly reduced in both experimentals fed for 7 weeks. With only Diet 2000 fed for 7 weeks total amounts of protein secreted in response to OXY increased significantly. 5. Protease activity in saliva in response to OCT increased significantly in experimentals with Diet 2000 fed for 4 weeks, whereas that was significantly reduced in both experimentals fed for 7 weeks. Amounts of cystatin in saliva in response to IPR were significantly reduced in experimentals with Diet 2000 fed for 3 and 4 weeks. 6. The levels of triiodothyronine, aldosterone and cystatin in sera in experimentals with Diet 2000 increased significantly when compared to those of controls with MF. 7. Amounts of bands at pI 6.1 and pI 7.2 in both experimentals increased in isoelectric focusing electrophoresis (IEF) of saliva in response to OCT. Many quantitative changes of spots were observed in two dimensional electrophoresis (2-D) . In these cases, C-10,S-1 and N-1 spots in both experimentals clearly increased. Number of spots in IPR-stimulated saliva was less than that of OCT-stimulated saliva and most spots were included in OCT-stimulated saliva. Characteristic spots in OXY-stimulated saliva were observed but no great changes of other spots were observed among the three groups. 8. Albumins (M.W.67 kDa, pI 6.0〜7.1) and secretory IgA α-chain (M.W.35 kDa, pI 5.6) were identified by the westernblotting method. In addition, main spots of parotid saliva in response to pilocarpine in 2-D was amylase (M.W.60 kDa, pI 6.7〜7.1). 9. Differences in the adsorption capacity to HA were observed in salivary proteins between MF and Diet 2000 groups but adsorbed components were not iden
福岡歯科大学学会の論文
1995-06-30

齲蝕誘発性高シュクロース食がラット顎下腺の分泌機能に及ぼす影響

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