Effects of the interval between removal and freezing of muscle biopsies on muscle fibre size.
Measurements of cross-sectional fibre areas are often performed in routine histopathologic diagnosis in cases of suspected neuromuscular disease. The methodologic error in fibre area measurements in duplicate muscle biopsies is reported, however, to be high and an animal model was therefore designed in order to study the mechanisms underlying this. The cross-sectional fibre area in the right soleus muscle, cut into 5 pieces and frozen after different lengths of time, was compared with that in the left soleus, which was frozen at the in situ length. It was found that this area was 23 +/- 6% larger (P less than 0.001) than in the control muscle, when the muscle sample was frozen immediately after being taken, as a result of contraction of the specimen. However, when the interval between removal of the sample and freezing was 2 min or longer, the fibre size was similar to the control muscle, but the muscle samples were still contracted and the decrease in muscle fibre size at longer intervals were accordingly due to a decrease in muscle fibre volume. It is concluded that the interval between removal and freezing of the biopsy is of vital importance for the fibre size.
Larsson
L
L
Department of Clinical Neurophysiology, Karolinska Hospital, Stockholm, Sweden.
Skogsberg
C
C
D000818:Animals; D001706:Biopsy; D005615:Freezing; D066298:In Vitro Techniques; D008297:Male; D009132:Muscles / Q000033:anatomy & histology*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors