Mitochondrial alterations in the spinal ganglion neurons in ageing rats.

An ultrastructural study of the mitochondria was performed in the 3-, 24-, and 32-month-old rats. Accumulation of "unusual" substances or structures was the most striking characteristic in senescent neuron mitochondria. Tubular or filamentous inclusions, modifications in matrix density, deposit of glycogen particles and electron-dense globules were observed. The various nature of these alterations and their different situation in the cristae or in the matrix, suggested that they could be the result of some specific oxidative metabolism dysfunctions associated with ageing.