A method for the ultrastructural preservation of tiny percutaneous needle biopsy material from skeletal muscle.

Skeletal muscle biopsies require transecting the muscle fibers resulting, in structural damage near the cut ends. Classically, the optimal ultrastructural preservation has been obtained by the use of relatively large biopsies in which the tissue fibers are restrained by ligating to a suitable retaining support prior to excision, and by examining regions at some distance from the cut ends. However, these methods require invasive surgical procedures. In the present study, we present and substantiate an alternative approach that allows for the excellent ultrastructural preservation of needle biopsy samples, even the very small samples obtained through tiny percutaneous needle biopsy (TPNB). TPNB represents an advantage, relative to standard muscle biopsy techniques and to other needle biopsies currently in use, as in addition to not requiring a skin incision, it leaves no scars in the muscle and requires an extremely brief recovery period. It is most appropriate for obtaining repeated samples in horizontal studies, e.g., in order to follow changes with athletic training and/or aging in a single individual and for studies of sarcopenic muscles in elderly patients. Due to the small size of the sample, TPNB may present limited usefulness for classical pathology diagnostics. However, it offers the major advantage of allowing multiple samples within a single session and this may be useful under specific circumstances.

Effects of local vibrations on skeletal muscle trophism in elderly people: mechanical, cellular, and molecular events.

Several studies have examined the effects of vibrations on muscle mass and performance in young healthy people. We studied the effects of vibrations on muscles of elderly male and female volunteers (65-85 years of age) diagnosed with sarcopenia. We applied mechanical vibrations locally (local vibrational training) to the thigh muscles at 300 Hz for a period of 12 weeks, starting with a session of 15 min stimulation once a week and increasing to three sessions of 15 min per week. Treated muscles displayed enhanced maximal isometric strength and increased content of fast MyHC-2X myosin. Single muscle fiber analysis did not show any change in cross-sectional area or in specific tension. Analysis of transcriptional profiles by microarray revealed changes in gene expression after 12 weeks of local vibrational training. In particular, pathways related with energy metabolism, sarcomeric protein balance and oxidative stress response were affected. We conclude that vibration treatment is effective in counteracting the loss of muscular strength associated with sarcopenia and the mode of action of vibration is based on cellular and molecular changes which do not include increase in fiber or muscle size.