Effects of potential therapeutic agents on copper accumulations in gill of Crassostrea virginica

Copper is an essential trace element for most organisms, but when present in excess, copper can have toxic effects due to its ability to generate free radical and oxidative stress. Bivalves, such as the Eastern Oyster Crassostrea virginica, are filter feeders that accumulate heavy metals and other pollutants from their environment. Copper is a major pollutant in Jamaica Bay and other aquatic areas. Previously it was determined that C. virginica seed, transplanted from an oyster farm to Jamaica Bay, readily accumulated copper and other pollutants into their tissues. My project studied the uptake of copper into oyster gill tissue and the effects of potential copper-blocking therapeutic agents. I used Atomic Absorption Spectrometry analysis to demonstrate that two potential agents, diltiazem, a therapeutic calcium channel blocker and p-aminosalicyclic acid, a therapeutic anti-inflammatory agent, were effective in blocking copper accumulations into oyster gill. In other experiments I showed that lanthanum, another calcium channel blocker, was unable to reduce copper accumulations in oyster gill tissue. I also used DMAB-rhodanine histochemistry staining technique for copper to confirm that copper was entering gill cells. This staining technique further demonstrated that Diltiazem was able to greatly reduce the cellular uptake of copper. The accumulation of copper into the gill and the toxic effects of copper on gill mitochondria could be of physiological significance to the growth and long-term health of oysters and other marine animals living in a copper polluted environment. Identifying agents and mechanisms which reduce copper accumulation and protect mitochondria is beneficial for understanding and therapeutic treatment of copper toxicity in humans.