Monday, October 8, 2012

Toxic Dioxin

Since its use by the US military to raze the Vietnamese forests and grasslands, Agent Orange has wreaked horrific damage to the Vietnamese people. Cancers, disabilities and birth defects all bear witness to its effects. Now a study looking 
into the effects of dioxins on gene expression has revealed that even three generations after exposure, diseases and problems caused by dioxin will be present in rats.

Today dioxins are found as industrial by-products, given off by waste incinerators and other processes. To investigate effects of its exposure, pregnant rats were administered TCDD, a dioxin component of Agent Orange. This dose was low for lab rats but higher than humans would experience in the environment, as well as for a different time period and method of dose delivery. The team found that subsequent generations, all the way to the original rats' "great grandchildren", had problems such as prostate cancer, ovarian diseases and kidney disease.

The way dioxins do this is by changing which genes are turned on and off. The DNA sequences are the same, but whether they are expressed or not changes (the study of inherited changes in gene expression is called epigenetics). While the findings are not directly applicable to humans, it demonstrates that the environment of our ancestors can be responsible for diseases and disorders today.

Photo credit: iStockphoto/Dmitry Oshchepkov

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