Mercury exposure is associated with increased risk of
cardiovascular disease and profound
cardiotoxicity. However, the correlation between Hg(2+)-mediated toxicity and alteration in cardiac
cytochrome P450s (Cyp) and their dependent
arachidonic acid metabolites has never been investigated. Therefore, we investigated the effect of acute
mercury toxicity on the expression of Cyp-epoxygenases and Cyp-ω-
hydroxylases and their associated
arachidonic acid metabolites in mice hearts. In addition, we examined the expression and activity of soluble
epoxide hydrolase (sEH) as a key player in
arachidonic acid metabolism pathway.
Mercury toxicity was induced by a single
intraperitoneal injection (IP) of 2.5 mg/kg of
mercuric chloride (HgCl₂). Our results showed that
mercury treatment caused a significant induction of the
cardiac hypertrophy markers,
atrial natriuretic peptide (
ANP) and
brain natriuretic peptide (BNP); in addition to
Cyp1a1, Cyp1b1, Cyp2b9, Cyp2b10, Cyp2b19,
Cyp2c29, Cyp2c38, Cyp4a10, Cyp4a12, Cyp4a14, Cyp4f13, Cyp4f15, Cyp4f16 and Cyp4f18 gene expression. Moreover, Hg(2+) significantly increased sEH
protein expression and activity levels in hearts of
mercury-treated mice, with a consequent decrease in 14,15-, and 11,12-epoxyeicosatrienoic
acids (EETs) levels. Whereas the formation of 14,15-, 11,12-, 8,9-dihydroxyeicosatrienoic
acids (DHETs) was significantly increased. In conclusion, acute Hg(2+) toxicity modulates the expression of several Cyp and sEH
enzymes with a consequent decrease in the cardioprotective EETs which could represent a novel mechanism by which
mercury causes progressive
cardiotoxicity. Furthermore, inhibiting sEH might represent a novel therapeutic approach to prevent Hg(2+)-induced
hypertrophy.