Davis W L, Jacoby B H, Craig K R, Wagner G, Harrison J W
Department of Cell Biology, Baylor University Medical Center, Dallas, TX.
J Endod. 1991 Jul;17(7):316-8. doi: 10.1016/S0099-2399(06)81698-5.
Information regarding the presence of the free radical scavenging (inactivating, dismutating) enzyme superoxide dismutase in human dental pulp was sought. Free radicals, such as the superoxide anion radical (O2-) and the hydroxyl anion radical (OH.), are powerful biological oxidants produced by phagocytes during the normal tissue response to injury and infection. Also produced is hydrogen peroxide (H2O2), an aggressive oxygen species formed by the reaction of superoxide with itself, i.e., a dismutation in which one molecule of O2- is oxidized by the other. These three reactive oxygen intermediates serve as part of the normal host biological defense mechanism for the inactivation of microorganisms and the breakdown of their toxic products. Both normal and inflamed dental pulps were assayed for the presence of this enzyme. Superoxide dismutase activity was identified in the normal pulpal tissues. There was a slight decrease in activity with age. In the inflamed pulpal tissues, enzyme activity was markedly and significantly increased in comparison to that in the normal tissues. These observations indicate that human dental pulp possesses an endogenous defense mechanism designed to protect the tissue components (cells and matrix) from the toxic effects of the reactive oxygen intermediates. In this regard, the inflammatory response of this specialized and somewhat isolated (compartmentalized) tissue is not unlike that seen in other connective tissues.
本研究旨在探寻人类牙髓中是否存在自由基清除（灭活、歧化）酶超氧化物歧化酶。自由基，如超氧阴离子自由基（O2-）和羟基阴离子自由基（OH.），是吞噬细胞在正常组织对损伤和感染的反应过程中产生的强大生物氧化剂。同时还会产生过氧化氢（H2O2），它是超氧化物自身反应形成的一种活性氧，即一个O2-分子被另一个氧化的歧化反应产物。这三种活性氧中间体是正常宿主生物防御机制的一部分，用于使微生物失活并分解其有毒产物。对正常牙髓和炎症牙髓均检测了这种酶的存在情况。在正常牙髓组织中鉴定出了超氧化物歧化酶活性。随着年龄增长，活性略有下降。在炎症牙髓组织中，与正常组织相比，酶活性显著且明显升高。这些观察结果表明，人类牙髓具有一种内源性防御机制，旨在保护组织成分（细胞和基质）免受活性氧中间体的毒性影响。在这方面，这种特殊且有点孤立（分隔）的组织的炎症反应与其他结缔组织中的炎症反应并无不同。
