Relationship between telomere length and early glutathione levels in the erythrocytes of zebra finches

Telomeres are repetitive DNA sequences at the end of chromosomes that protect them from degradation. They have been the focus of intense research because short telomeres would predict accelerated ageing and reduced longevity in vertebrates. Oxidative stress is considered a physiological driver of the telomere shortening and, consequently, short lifespan. Among molecules fighting against oxidative stress, glutathione is involved in many antioxidant pathways. Literature supports that oxidative stress may trigger a compensatory “hormetic” response increasing glutathione levels and telomere length. Here we tested the link between total glutathione concentration and telomere length in captive birds (zebra finches; Taeniopygia guttata). Total glutathione levels were experimentally decreased during birds’ growth using a specific inhibitor of glutathione synthesis (buthionine sulfoximine; BSO). We monitored the birds’ reproductive performance in an outdoor aviary during the first months of life and their almost nine-year longevity. We predicted that if glutathione protects telomeres from oxidative stress-induced telomere attrition, a positive correlation between telomere length and glutathione concentration in erythrocytes of control individuals should emerge. Similarly, we predicted that since BSO-treated zebra finches endured higher oxidative stress than controls, they should have also developed shorter telomeres in their erythrocytes and reduced longevity and reproductive outcomes. The current dataset allows testing these predictions.