Quantitative changes in mitochondria of spinal ganglion neurons in aged rabbits

Abstract

Within the context of our research on the age-related structural changes in spinal ganglia, we studied the mitochondria of the neuronal perikaryon in the spinal ganglia of 12-, 42-, and 79-month-old rabbits. Both the volume of the perikaryon and the total mitochondrial mass within the perikaryon increased significantly passing from young adult to old animals. Hence, there is no net loss of mitochondria in these neurons with age. Since, however, the volume of the perikaryon increased by more than 63% while the total mitochondrial mass within the perikaryon increased by only 18%, the mean percentage of perikaryal volume occupied by mitochondria decreased with age. This decrease is only in very minor part a consequence of lipofuscin accumulation, so that the ratio between the total mitochondrial mass and the functionally active volume of cytoplasm decreased with age. Possible causes of this decrease are discussed briefly. Moreover, while the mitochondrial structure did not change, mitochondrial size increased with age. Finally, in each of the three age groups both the mean percentage volume of mitochondria and the mean mitochondrial size were very similar in large light and in small dark neurons.

Age-related quantitative changes in mitochondria of satellite cell sheaths enveloping spinal ganglion neurons in the rabbit

“…Comparison of the present data on mitochondria in satellite cell sheaths with those from the nerve cell bodies of the same ganglia [12] showed the following. The mean percentage of cytoplasmic volume occupied by mitochondria was greater in nerve cell bodies than satellite cell sheaths.…”

“…This suggests that the mitochondrial changes observed in neurons [12] and their associated satellite cells (present paper) of spinal ganglia do not lead to significant neuronal loss. This suggestion is consistent with observation of no reduction [5,10,16] or only a small reduction [1] in the number of spinal ganglion neurons with advancing age.…”

“…rently thought to play in the ageing process (for reviews see [4,9,15,17,25,26]), we have previously quantitatively investigated age-related changes in mitochondria of rabbit spinal ganglion neurons [12]. We now continue this research by studying the age-related changes in the mitochondria of the satellite cell sheaths that envelope these neurons.…”

Oxidative Stress‐Induced Depolymerization of Microtubules and Alteration of Mitochondrial Mass in Human Cells

“…This is one of the most prominent clinical hallmarks in mitochondrial diseases such as chronic progressive external ophthalmoplegia (CPEO) and myoclonic epilepsy and ragged‐red fiber (MERRF) syndromes. Morphologic features of giant mitochondria were observed in nerve and muscle tissues of elderly subjects and patients with mitochondrial disorders 1,2. Moreover, giant mitochondria also appeared in mtDNA‐depleted ρ 0 cells,3 and mtDNA depletion caused a reduction in the amount of mitochondrial inner membranes 4.…”

Mitochondria in Perineuronal Satellite Cell Sheaths of Rabbit Spinal Ganglia: Quantitative Changes during Life

“…In view of the central role attributed to mitochondria in the aging process [for reviews, see Miquel et al, 1980;Wallace, 1992;Kadenbach et al, 1995;Ozawa, 1995;Cortopassi and Wong, 1999;Walter et al, 1999], we have quantitatively investigated age-related changes in mitochondria of spinal ganglion neurons in the rabbit [Ledda et al, 2001;Martinelli et al, 2006]. In spinal ganglia, each nerve cell body is usually enveloped by its own satellite cell sheath (SCS), thus constituting a structural and probably also a metabolic unit [for reviews, see Pannese, 1981Pannese, , 1994.…”