Plasticity of skeletal muscle studied by stereology

english

2004

volume 23, issue 3

Muscle, Skeletal    Anatomy And Histology   Blood Supply    Transplantation    Myosin Heavy Chains   Muscle Fibers, Fast-Twitch    Muscle Fibers, Slow-Twitch   Muscle Fibers   Cytology    Rats, Wistar   Electric Stimulation   Bupivacaine    Sarcomeres    Cadherins    Microscopy, Confocal 

Društvo za stereologijo in kvantitativno analizo slike
(Obvezni izvod spletne publikacije)

The present contribution provides an overview of stereological methods appliedin the skeletal muscle research at the Institute of Anatomy of the Medical Faculty in Ljubljana. Interested in skeletal muscle plasticity we studied three different topics: (i) expression of myosin heavy chain isoforms in slow and fast muscles under experimental conditions, (ii) frequency of satellite cells in young and old human and rat muscles and (iii) capillary supply of rat fast and slow muscles. We analysed the expression of myosin heavy chain isoforms within slow rat soleus and fast extensor digitorum longusmuscles after (i) homotopic and heterotopic transplantation of both muscles, (ii) low frequency electrical stimulation of the fast muscle and (iii) transposition of the fast nerve to the slow muscle. The models applied were able to turn the fast muscle into a completely slow muscle, but not vice versa. One of the indicators for the regenerative potential of skeletal muscles is its satellite cell pool. The estimated parameters, number of satellite cells per unit fibre length, corrected to the reference sarcomere length (Nsc/Lfib) and number of satellite cells per number of nuclei (myonuclei and satellite cell nuclei) (Nsc/Nnucl) indicated that the frequencyof M-cadherin stained satellite cells declines in healthy old human and rat muscles compared to young muscles. To access differences in capillary densities among slow and fast muscles and slow and fast muscle fibres, we haveintroduced Slicer and Fakir methods, and tested them on predominantly slowand fast rat muscles. Discussing three different topics that require different approach, the present paper reflects the three decades of the development of stereological methods: 2D analysis by simple point counting in the 70's, the disector in the 80's and virtual spatial probes in the 90's. In all methods the interactive computer assisted approach was utilised.

16.09.2009