Prenatal ethanol exposure alters ventricular myocyte contractile function in the offspring of rats: influence of maternal Mg2+ supplementation.
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| Abstract |
Fetal alcohol syndrome (FAS) is often associated with cardiac hypertrophy and impaired ventricular function in a manner similar to postnatal chronic alcohol ingestion. Chronic alcoholism has been shown to lead to hypomagnesemia, and dietary Mg2+ supplementation was shown to ameliorate ethanol- induced cardiovascular dysfunction such as hypertension. However, the role of gestational Mg2+ supplementation on FAS-related cardiac dysfunction is unknown. This study was conducted to examine the influence of gestational dietary Mg2+ supplementation on prenatal ethanol exposure-induced cardiac contractile response at the ventricular myocyte level. Timed-pregnancy female rats were fed from gestation day 2 with liquid diets containing 0.13 g/L Mg2+ supplemented with ethanol (36%) or additional Mg2+ (0.52 g/L), or both. The pups were maintained on standard rat chow through adulthood, and ventricular myocytes were isolated and stimulated to contract at 0.5 Hz. Mechanical properties were evaluated using an IonOptix soft-edge system, and intracellular Ca2+ transients were measured as changes in fura-2 fluorescence intensity (Delta FFI). Offspring from all groups displayed similar growth curves. Myocytes from the ethanol group exhibited reduced cell length, enhanced peak shortening (PS), and shortened time to 90% relengthening (TR90) associated with a normal Delta FFI and time to PS (TPS). Mg2+ reverted the prenatal ethanol-induced alteration in PS and maximal velocity of relengthening. However, it shortened TPS and TR90, and altered the Delta FFI, as well as Ca2+ decay rate by itself. Additionally, myocytes from the ethanol group exhibited impaired responsiveness to increased extracellular Ca2+ or stimulating frequency, which were restored by gestational Mg2+ supplementation. These data suggest that although gestational Mg2+ supplementation may be beneficial to certain cardiac contractile dysfunctions in offspring of alcoholic mothers, caution must be taken, as Mg2+ supplementation affects cell mechanics itself.
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| Authors | L E Wold, F L Norby, K K Hintz, P B Colligan, P N Epstein, J Ren |
| Journal | Cardiovascular toxicology (Cardiovasc Toxicol) Vol. 1 Issue 3 Pg. 215-24 ( 2001) ISSN: 1530-7905 [Print] United States |
| PMID | 12213974 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.) |
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