The typical naked mole¹ rat lives 25 to 30 years, during which it shows little decline in activity, bone health, reproductive capacity and cognitive² ability. What is the secret to this East African rodent³'s long, healthy life? Scientists from the United States and Israel found a clue. From infancy⁴ to old age, naked mole rats are blessed with large amounts of a protein essential for normal brain function.

"Naked mole rats have the highest level of a growth factor called NRG-1 in the cerebellum（小脑） . Its levels are sustained throughout their life, from development through adulthood," said Yael Edrey, doctoral student at The University of Texas Health Science Center San Antonio's Barshop Institute for Longevity⁵ and Aging Studies.

Comparison across 7 species

The Barshop Institute has the largest colony of naked mole rats in the U.S. -- 2,000 rodents⁶ scampering⁷ around a network of tubes and cages in humid conditions that mimic⁸ their natural underground habitat. Edrey is the lead author of research that compared lifelong NRG-1 levels across seven species of rodents, from mice and guinea pigs（豚鼠） to blind mole rats and Damaraland mole rats.

NRG-1 levels were monitored in naked mole rats at different ages ranging from 1 day to 26 years. The other six rodent species have maximum life spans of three to 19 years.

The cerebellum coordinates⁹ movements and maintains bodily equilibrium¹⁰（均衡，平静） . The research team hypothesized that long-lived species would maintain higher levels of NRG-1 in this region of the brain, with simultaneous healthy activity levels.

Among each of the species, the longest-lived members exhibited the highest lifelong levels of NRG-1. The naked mole rat had the most robust¹¹ and enduring supply. "In both mice and in humans, NRG-1 levels go down with age," Edrey said.