Contractile properties of rat skeletal muscles following storage at 4 degrees C

The purpose of this study was to assess the potential of preservation solut ions for protecting skeletal muscle function during storage at 4 degrees C. The soleus and the cutaneus trunci (CT) from the rat were stored for 2, 8 or 16 h at 4 degrees C in University of Wisconsin solution (UW), HTK-Bretsc hneider solution (HTK) or Krebs-Henseleit solution (KH). After storage, mus cles were stimulated electrically to analyse the isometric contractile prop erties, such as the maximum tetanic tension (P-0). Histological analysis wa s also performed. In separate experiments, the effect of the diffusion dist ance on muscle preservation was studied by bisecting the soleus. After 8 h of storage in UW or HTK, the contractile properties of the CT were similar to those of the control, whereas those of the soleus were reduced (P-0 valu es of 16% and 69% of control in UW and HTK respectively). At 16 h, the cont ractile properties of the CT (P-0 28%) were again better preserved than tho se of the soleus (P-0 9%). Muscle function deteriorated most after storage in KH (P-0 at 16 h : soleus, 3%; CT, 17%). The bisected soleus was equally well preserved as the CT (P-0 of bisected soleus at 8 h in UW and HTK: 86%) . The functional data corresponded well with the histological data, which s howed increasing muscle fibre derangement with increasing storage time. For both muscles and all solutions, the threshold stimulus current increased w ith increasing storage time (control, 0.1 mA; 16 h, 1.2 mA) and was strongl y correlated with the deterioration in contractile properties. It is conclu ded that, at 4 OC, muscle is preserved better in UW and HTK (intracellular- like solutions) than in KH (extracellular-like solution). The soleus and CT were best protected in HTK. The diffusion distance is a critical factor fo r successful preservation of muscle function at 4 degrees C. The reduced fu nction after 16 h of storage at 4 OC was caused by hypercontraction and nec rosis of about 25% of the muscle fibres, and by deterioration of the electr ical component of excitation-contraction coupling of the remaining fibres.