Background: Paraoxonase 1 (PON1) is a protein found associated with high density lipoprotein (HDL), thought to prevent oxidative modification of low-density lipoprotein (LDL). This enzyme has been implicated in lowering the risk of cardiovascular disease. Anoxia-reoxygenation and oxidative stress are important elements in cardiovascular and cerebrovascular disease. However, the role of PON1 in anoxia-reoxygenation or anoxic injury is unclear. We hypothesize that PON1 prevents anoxia-reoxygenation injury. We set out to determine whether PON1 expression in Drosophila melanogaster protects against anoxia-reoxygenation (A-R) induced injury.
Methods: Wild type (WT) and transgenic PON1 flies were exposed to anoxia (100% Nitrogen) for different time intervals (from 1 to 24 hours). After the anoxic period, flies were placed in room air for reoxygenation. Activity and survival of flies was then recorded.
Results: Within 5 minutes of anoxia, all flies fell into a stupor state. After reoxygenation, survivor flies resumed activity with some delay. Interestingly, transgenic flies recovered from stupor later than WT. PON1 transgenic flies had a significant survival advantage after A-R stress compared with WT. The protection conferred by PON1 expression was present regardless of the age or dietary restriction. Furthermore, PON1 expression exclusively in CNS conferred protection.
Conclusion: Our results support the hypothesis that PON1 has a protective role in anoxia-reoxygenation injury, and its expression in the CNS is sufficient and necessary to provide a 100% survival protection.