胶原酶对人根面牙本质胶原蛋白降解作用的实验研究

目的：探讨胶原酶对脱矿后的人牙根面牙本质胶原蛋白的降解作用。方法：根面牙本质标本用pH5.0的乳酸37℃孵育脱矿。分别于第1、7、14、21和28天取孵育液，10000r/min，4℃离心，上清液作Ca^2 测定和羟脯胺酸分析。脱矿后的标本加入pH7.4的胶原酶溶液，37℃孵育7d。孵育液10000r/min、4℃离心，上清液作羟脯胺酸分析。结果：随着时间的延长，Ca^2 释放量逐渐增加，增加量有显著性差异（P＜0．05）；胶原蛋白的释放量随时间的延长而增加，但增加量无显著性差异。如胶原酶降解后，当Ca^2 少于80.01μmol/cm^2时，胶原蛋白释放量增加明显（P＜0．001）；以后虽然Ca^2 浓度增加，胶原蛋白的增加量无显著性差异。结论：胶原酶对根面牙本质胶原蛋白的降解作用与Ca^2 密切相关。保留龈损区的矿物质对于预防胶原纤维的降解、促进早期根面龋的再矿化是非常重要的。

A Study on the Rate of Collagenase in the Degradation of Human Root Dentin in vitro

Objective The purpose of this study was to evaluate the effect of degradation of human root dentin collagen treated with collagenase after demineralization. Methods The root dentin samples were demineralized by incubating with pH5.0 lactate acid at 370C.The incubation solutions were taken on days 1,7,14,21 and 28,and centrifuged 10 000r/min at 40C.The supernature solutions were analyzed for Ca2+ and hydroxyproline.The demineralized root samples were incubated with pH7.4 collagenase solution for 7 days at 370C.The incubation solutions were centrifuged 10 000r/min at 40C and analyzed for hydroxyproline. Results The release of Ca2+ increased and had significant differences at all observation periods within 28 days(p<0.05).There were no significant differences of the amount of degradable collagen during the nonenzymatic procedure(p>0.05).The amount of collagenase-degradable collagen was proportional to the calcium released until a plateau value at a calcium loss of about 80.01 umol/cm2 was reached. Conclusion The degradability of collagenase is in close association with calcium released. The retention of mineral is of relevance for lesion arrestment or remineralization of early root caries.