Mice Lacking One Muscle Enzyme Get No Boost From Exercise
Graded Preliminary — experiments in mice with a gene removed from muscle over 20 months, plus muscle samples from 38 men; the treatments have not been tested in people.
Animal study. Findings may not carry over to people, which is why the grade is capped at Preliminary.
- Design
- Animal study
- Participants
- 38
- Duration
- 20 months
- Funding
- National Health and Medical Research Council of Australia
Mice without the muscle enzyme NOX4 gained nothing from exercise training and declined faster with age.
Working muscles produce reactive oxygen molecules. An enzyme called NOX4 makes such molecules, and in doing so it switches on a protective program in the cell, run by a master switch called NFE2L2. Old mice and older men had less NOX4 protein in their muscles. When mice lacked the enzyme only in muscle, their bodies declined much faster with age.
The mice ate a normal diet for 20 months. Without muscle NOX4 they became frailer and gained more fat. They had higher inflammation markers in the blood, responded poorly to insulin and developed an inflamed fatty liver. In 12-month-old mice, exercise training raised NOX4 back to the level of young animals. Without NOX4, the training gains did not appear. Restoring NOX4 with a virus, or giving sulforaphane for four weeks, corrected much of the damage. Sulforaphane is a plant compound that turns on the protective program. Liver scarring did not improve.
The human side rests on muscle samples from 18 men aged 65 to 71 and 20 young men. In the older men, the protective program was less active. Whether sulforaphane helps older people was not tested: the treatments were tried only in mice.
Disclaimer: Research summaries are provided for informational purposes only and do not constitute medical advice. Always consult a qualified healthcare professional before making changes to your health routine.