Age-Induced Hair Greying: The Multiple Effects of Oxidative Stress

Hair greying, a sign of aging, resulted from oxidative stress affecting various mechanisms within hair follicles. Key factors included defects in melanocyte stem cells and follicular melanocyte death. Oxidative damage, accelerated by BCL-2 gene depletion, led to apoptosis and reduced melanocyte stem cell repopulation. Aging reduced the expression of anti-oxidant proteins like BCL-2 and TRP-2, weakening the follicle's defense system and increasing oxidative stress. This caused a significant drop in catalase activity, leading to hydrogen peroxide accumulation and melanocyte death. However, amelanotic melanocytes in the outer root sheath were less affected and survived longer. Understanding these processes could help develop therapies to prevent or reverse hair greying.