Senescent Changes in the Kidney of the Yellow Mud Turtle Kinosternon flavescens

Abstract

Current literature suggests that reptiles do not undergo senescence. This study addresses age-related changes that occur in the kidneys of reptiles and compares them to senescent changes in mammalian kidneys. Kidney sections from a wild population of turtles ranging in age from 6 to 35 years were examined histologically by light and electron microscope. Kidney tubules of the older turtles showed a statistically significant greater deposition of a pigment believed to be lipofuscin or ceroid than did young turtles. Glomeruli in the oldest turtles had significantly fewer glomerular arterioles, and a significant increase in connective tissue in the glomerular tuft. Electron microscope studies indicated that glomeruli became smooth and simplified with advanced age. Foot processes lost their regular arrangement and became wider. Pedicels became irregular or degenerate. Fine structures of reptilian kidney appeared to be simpler and more organized than mammal kidney, but age-related changes were similar.