Caries Res. 2017;51(6):576-581. doi: 10.1159/000479896. Epub 2017 Oct 13.
The enzymatic degradation of dentin organic matrix occurs via both the action of matrix metalloproteinases (MMPs) and cysteine cathepsins (CCs). Zinc can prevent collagen hydrolysis by MMPs. However, its effect on the activity of dentin-bound CCs is not known. The aim of this study was to investigate the effect of zinc on matrix-bound cathepsin K and MMP activity in dentin. Completely demineralized dentin beams were divided into test groups (n = 9) and incubated at 37°C in an incubation media (1 mL) containing ZnCl2 of 0.02 (physiological level, control), 0.2, 0.5, 1, 5, 10, 20, 30, or 40 mM. The dry mass changes of the beams were determined, and incubation media were analyzed for cathepsin K- and MMP-specific collagen degradation end products - CTX (C-terminal cross-linked telopeptide of type I collagen) and ICTP (cross-linked carboxy-terminal telopeptide of type I collagen) - at 1, 3, and 7 days of incubation. The mass loss of the beams decreased when the zinc level in the incubation media was ≥5 mM (p < 0.05). The release of liberated collagen degradation telopeptides decreased in accordance with the decrease in the mass loss rates of the beams. Cathepsin K-induced dentin collagen degradation can be strongly inhibited by zinc. Zinc levels of ≥5 mM can be considered as a reliable threshold for the stabilization of dentin matrices.
牙本质有机基质的酶降解既通过基质金属蛋白酶（MMPs）的作用，也通过半胱氨酸组织蛋白酶（CCs）的作用发生。锌可以防止 MMP 对胶原蛋白的水解。然而，其对牙本质结合 CCs 活性的影响尚不清楚。本研究旨在探讨锌对牙本质基质结合组织蛋白酶 K 和 MMP 活性的影响。完全脱矿的牙本质梁被分为实验组（n=9），并在 37°C 的孵育介质（1 mL）中孵育，其中含有 0.02（生理水平，对照）、0.2、0.5、1、5、10、20、30 或 40 mM 的 ZnCl2。测定梁的干质量变化，并在孵育 1、3 和 7 天时分析孵育介质中组织蛋白酶 K 和 MMP 特异性胶原蛋白降解终产物 - CTX（I 型胶原 C 端交联肽）和 ICTP（I 型胶原交联羧基末端肽）- 。当孵育介质中的锌水平≥5 mM 时（p<0.05），梁的质量损失减少。释放的游离胶原蛋白降解末端肽的减少与梁质量损失率的降低一致。锌可以强烈抑制组织蛋白酶 K 诱导的牙本质胶原蛋白降解。锌水平≥5 mM 可被认为是稳定牙本质基质的可靠阈值。
