Marked by pain

Chronic pain can be marked in the DNA

The work was published in the open-access journal PlosOne. To model pain, scientists injured nerves in the tight of laboratory mice through surgery. The purpose of the study? To understand if the lesion remains in the DNA of cells as a mark.

The research showed that epigenetic marks can be found in the DNA of cells from brains of mice suffering from chronic pain. Epigenetics comprises the chemical marks in the DNA and associated proteins that are the product of signals and stimuli arising from different sources. In the same way as each cell is characterized by its genes (genetics), it is now clear that cells are also characterized by the chemical modifications in those genes (epigenetics). Even if epigenetics cannot change the sequence of genes in the DNA molecule, it can control the way genes are "read". In this experiment, peripheral nerve injury led to epigenetic alterations in the brains of the mice, at the level of DNA, as if to remind the animals of the lesion suffered 6 months before.

credits: Ana Costa
A new system for quantifying pain can
originate from the new observations.  
 It is not clear yet which consequences originate from the epigenetic marks in specific regions of the brain. To better understand the mechanism observed, scientists induced symptom relief, to some extent, by means of exposing the mice to modified cages (a procedure somehow similar to a series of physiotherapy sessions). The changes in the symptoms were associated with changes in the epigenetic marks of the DNA molecule in the brain cells. Scientists learnt that the marks in the DNA could be related by the levels of pain.

In the future, will this information be useful to those patients suffering from chronic pain, regardless of its cause? The authors of this study are optimistic about the future and believe that one day it will be possible to treat pain if the epigenetic marks in the DNA are modulated by clinicians. And even if the treatment of pain is far from reality, these new observations can start by serving another purpose: that of quantifying pain. Currently, assessing pain in complex due to subject to subject variability. However, establishing a more objective method of quantification could be beneficial for the correct diagnosis and treatment of various pathologies. This new study can be the basis for a new, epigenetics-based, quantification method for pain.