Free radicals help tissue regeneration
The regeneration process requires reactive oxygen species
LifeSciencesToday based on the materials of the University of Manchester: The secrets of a tadpole's tail and the implications for human healing
Studying the regeneration process on the example of amputated tadpole tails, scientists at the University of Manchester have made an amazing discovery that can have a serious impact on the further development of regenerative medicine.
Unlike mammals, including humans, frogs and salamanders have amazing regenerative abilities. So, to grow a new tail to replace the lost one, the tadpole needs only one week. Professor Enrique Amaya and his group have been studying the regeneration process for several years in the hope of eventually using the information obtained to increase the regenerative abilities of the human body.
In an earlier study, Professor Amaya's group identified genes that are activated during tail regeneration. As it turned out, these several genes are involved in metabolism and, in particular, are associated with the formation of reactive oxygen species (ROS) – molecules with extremely high reactivity containing oxygen in their composition. This was an unexpected discovery, since ROS are traditionally considered substances that damage proteins and nucleic acids, that is, they have a negative effect on the cell.
The scientists decided to continue studying this unusual phenomenon, and the results of their new study are published in the journal Nature Cell Biology (Love et al., Amputation-induced reactive oxygen species are required for successful Xenopus tadpole tail regeneration).
When studying the role of reactive oxygen species in the process of tail regeneration, they evaluated the presence of H 2 O 2 (hydrogen peroxide, widespread in cells), using fluorescent imaging in their experiments. Using this method, they were able to establish that the levels of H 2 O 2 noticeably increase immediately after the amputation of the tail and remain elevated throughout the regeneration process, lasting several days.
"We were very surprised by such high levels of reactive oxygen species. Traditionally, it is believed that ROS negatively affect the state of cells, but in this case they seemed to have a positive effect," Professor Amaya comments on the results of the study.
To assess how important the presence of reactive oxygen species is for the regeneration process, scientists limited their formation by two different methods. The first was the use of chemicals, including antioxidants; the second was the removal of genes responsible for the production of ROS. In both cases, the regeneration process was suppressed, and the tail was not restored.
"The decrease in ROS levels was accompanied by suppression of tissue growth and regeneration. Our study shows that reactive oxygen species are important for initiating and maintaining a regenerative response. In addition, the formation of ROS is important for the activation of Wnt signaling, which is involved in almost all studied regeneration systems, including those found in the human body. Considering how often we are told that antioxidants are good for health, it is amazing that they have such a negative effect on tissue repair," Professor Amaya continues.
Professor Amaya's research was published just a few days after the article by Nobel Prize winner and one of the discoverers of the DNA structure James Watson, who believes that antioxidants can be harmful in the late stages of cancer.
"It is very interesting that recently two papers have been published suggesting that antioxidants may not always be useful. Our data and the results obtained by others lead to a radical change in the understanding of the relative benefits and negative effects of oxidants and antioxidants on human health, as well as to the recognition that oxidants, such as ROS, can really play one or another important and useful role in healing and regeneration," Professor Amaya commented on recent discoveries..
His group plans to continue studying the role of reactive oxygen species in the healing and regeneration processes at a deeper level. Scientists hope to find out whether it is possible to enhance the regenerative abilities of the human body by manipulating ROS levels.
Portal "Eternal youth" http://vechnayamolodost.ru23.01.2013