Recovery from immobilisation: responses of fast-twitch muscle fibres to spontaneous and intensive exercise in rat calf muscles  M Venojärvi, M Kvist, M Atalay, L Jozsa, H Kalimo  Pathophysiology  Volume 11, Issue 1, Pages 17-22 (July 2004) DOI: 10.1016/j.pathophys.2003.10.002

Fig. 1 Changes in relative bodyweights at different times. The mean weights of the experimental groups at Day 0 and at various sampling times were compared. For comparison between the control group and the immobilisation group, the mean weights at cast fixation (immobilisation) and removal (Day 0) were compared. The values represent percentual differences between the mean values at Day 0 and the sampling days. Pathophysiology 2004 11, 17-22DOI: (10.1016/j.pathophys.2003.10.002)

Fig. 2 Histological analyses of skeletal muscles after immobilisation and subsequent spontaneous and intensive exercise. Typical findings in hematoxylin and eosin staining: (A) two necrotic muscle fibres (#) of plantaris muscle at Day 0 in the IM group and (B) a necrotic muscle fibre (#) in plantaris muscle at 6 days after cast removal in the IM+AM group. Inflammatory cells (arrow) were observed at Day 6 in the IM+FM group: (C) between muscle fibres in tibialis anterior muscle and (D) in lateral gastrocnemious muscle. Magnification: 40×. Pathophysiology 2004 11, 17-22DOI: (10.1016/j.pathophys.2003.10.002)

Fig. 3 Histochemical analyses of skeletal muscle after immobilisation and subsequent spontaneous and intensive exercise. Examples of pathological findings: (A) Myofibril hypercontraction (open arrow) (IM+AM, Day 3). (B) Partial rupture in slow oxidative muscle fibre (open arrow) (IM+AM, Day 1). (C) Ruptures in slow oxidative muscle fibre (star) and fast glycolytic fibre (dollar) (IM+AM, Day 6). (D) In the middle, in the superior part hypercontraction (open arrow) and rupture and in the inferior part myofibril necrosis and debris (black arrow) (IM+AM, Day 3). Magnification: 40× for all panels. All images are from plantaris muscle. ATPase staining after preincubation, pH 4.6. Pathophysiology 2004 11, 17-22DOI: (10.1016/j.pathophys.2003.10.002)

Fig. 4 Immunohistochemical assay for MHC-d positive fibres after immobilisation and subsequent spontaneous and intensive exercise. No positive cells were present in any group. (A) MHC-d staining for m. plantaris (IM+AM, Day 6). (B) Positive control; the sample was taken from a mechanically injured m. soleus 7 days after the injury. MHC-d positive fibre (black arrow). Magnification: 10× for Panel A and 20× for Panel B. Pathophysiology 2004 11, 17-22DOI: (10.1016/j.pathophys.2003.10.002)

Fig. 5 β-Glucuronidase activity (β-GU) in tibialis anterior (A), lateral gastrocnemius (B) and plantaris (C) muscles after immobilisation and subsequent spontaneous and intensive exercise. Statistical analyses and values in logarithmic forms. # P>0.05 using Tukey’s post-hoc test after one way ANOVA. Pathophysiology 2004 11, 17-22DOI: (10.1016/j.pathophys.2003.10.002)