Low radiation doses extend human life, Russian biologist says. Ionizing radiation affects genes, which are responsible for cell ageing.
      
      Billions of cells are exposed to natural ionizing radiation. Evolution should have created an effective means for protecting cells from small radiation doses. Thus, the fact that X-rays and gamma rays in low and medium doses extend life of various laboratory animals on 10-29% is not surprising.
      
      Small doses of radiation promote immunity and cell division, as well as initiate other mechanisms of cell defense. But another explanation exists. Russian biologist tends to think that exposure to radiation damages DNA molecules and causes formation of free radicals, which in their turn, lead to premature aging and death of cells. However, first cells that die are usually the most sensitive to stress and unable to repair their DNA. Death of these cells does no harm to the whole organism, because new healthy cells quickly replace dead ones. Perhaps, this is the way an organism reacts on low radiation does and on any other externally induced stress.
      
      Stress and radiation probably affect either some genes of tolerance to stress, responsible for DNA reparation and for increasing antioxidant protection, or apoptosis genes. Scientists already know some of said genes, which launch processes, slowing down ageing process.
      
      Source: Science News