Wrinkled skin and hair loss are hallmarks of ageing. However, scientists reversed ageing-associated skin wrinkles and hair loss in a mouse model.
In a mouse model developed at the University of Alabama at Birmingham, Keshav Singh, Ph.D., and colleagues found when a change leading to mitochondrial dysfunction is induced; the mouse develops wrinkled skin and extensive, visible hair loss in a matter of weeks.
When the mitochondrial function is restored by turning off the gene responsible for mitochondrial dysfunction, the mouse returns to smooth skin and thick fur, indistinguishable from a healthy mouse of the same age.
Importantly, the mutation that triggers this is in a nuclear gene affecting mitochondrial function, the tiny organelles known as the powerhouses of the cells.
In humans, a decline in mitochondrial function is seen during ageing, and mitochondrial dysfunction can drive age-related diseases.
A depletion of the DNA in mitochondria is also implicated in human mitochondrial diseases, cardiovascular disease, diabetes, age-associated neurological disorders, and cancer.
The mutation in the mouse model is induced when the antibiotic doxycycline is added to the food or drinking water. This causes depletion of mitochondrial DNA because the enzyme to replicate the DNA becomes inactive.
In four weeks, the mice showed gray hair, reduced hair density, hair loss, slowed movements and lethargy, changes that are reminiscent of natural ageing.
Dramatically, this hair loss and wrinkled skin could be reversed by turning off the mutation.
Little change was seen in other organs when the mutation was induced, suggesting an important role for mitochondria in skin compared to other tissues.
The wrinkled skin showed changes similar to those seen in both intrinsic and extrinsic ageing -- intrinsic ageing is the natural process of ageing, and extrinsic ageing is the effect of external factors that influence ageing, such as skin wrinkles that develop from excess sun or long-term smoking.
Reversal of the mutation restored mitochondrial function, as well as the skin and hair pathology. This showed that mitochondria are reversible regulators of skin ageing and loss of hair, an observation that Singh calls "surprising."
The full findings are present in the journal - Cell Death and Disease.