29-30 January, 2020 - Szeged, Hungary


Abstract details

Age-related degeneration in the motor endplates and axons of mice leaves the motoneuron soma unaffected


Zoltán Fekécs1, Krisztián Pajer1, Bernát Nógrádi2, Roland Patai2, László Siklós2, Antal Nógrádi1

1 Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Szeged, Hungary

2 Department of Biophysics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary

Growing evidence from animal models and patients suggests that aging affects motor end plates and thus the innervation of skeletal muscles. The cause and the time course of these degenerative processes are unknown, and they may involve less exercise associated with age and spontaneous degeneration of the end plates, or both. Here we show that there are minor degenerative changes in the motor axons and their terminals while sensory axons remain largely unaffected. Axonal degeneration is already detectable in some of the axons in both the ventral roots and peripheral nerves of 6 months old C57BL/6 mice. These changes were accompanied by an increased number of pathological motor end plates (as compared to 3 months old mice) involving various forms of degenerating end plates in the EDL and TA muscles. At later time points (12, 18 and 24 months) progressive changes are present in both the peripheral nerves and muscles. Motoneurons show no decrease in their numbers but axonal transport processes appear to be severely affected by aging. Tension recording from these muscles shows a slightly decreasing tetanic force produced by aging animals, while the number of motor units decreases more progressively. Calcium histochemistry displays differential changes in the motor end plates and in the motoneurons. These changes suggest that aging affects mainly the distal parts of the motor unit while the perikaryon remains preserved for long time. Funding: Economy Development and Innovation Operative Programme (GINOP 2.3.2-15-2016-00034)