1. The purpose of this study was to assess the potential of various preservation solutions, originally designed for solid organs, to protect muscle function during cold storage. 2. The soleus (SOL) and the cutaneous trunci (CT) muscle from the rat were isolated and stored for 2, 4 or 8 h at 10°C. The solutions used, listed in order from an intracellular to an extracellular-like composition, were: University of Wisconsin (vw), EuroCollins (EC), HTK-Bretschneider (HTK), reversed St. Thomas' Hospital ( STZ) and Krebs-Henseleit (KH). After cold storage, the muscles were tested by direct electrical stimulation to obtain the maximum twitch tension (Pt) and the maximum tetanus tension (Po). Subsequently, the muscles were prepared for morphological analysis. 3. In general, storage at 10°C caused a gradual decrease of Pt and PO with time. After 8 h of storage in the extracellular-like solutions KH and STz, the PO was about 50% (SOL) and 35% (CT) of control.Eight hours of storage in intracellular-like solutions resulted in a PO of 50% of control for HTK, in a PO of 40% (SOL) and 67% (CT) for UW, but in a Po of 5% (SOL) and 26% (CT) for EC. These findings corresponded well with the morphological observations. 4.It is concluded that the effects of 10°C storage on skeletal muscle function are not predominantly determined by the intra-or extracellular-like composition of the solutions used. Both U W and HTK were most effective (P0>50% of control) in preserving muscle function.

Histidine-tryptophan-ketoglutarate (HTK) preserves rat muscle function during cold storage. We examined the effect of HTK perfusion on preservation of microvascular function during 4 h of warm ischemia and subsequent reperfusion (I/R) in the rat cremaster muscle. Leukocyte-endothelium interactions, capillary perfusion, and arteriole diameters were quantified prior to HTK-perfusion and/or ischemia, and at 0, 1, and 2 h after restoration of blood flow. In all groups, the number of rolling leukocytes increased with time, whereas I/R induced a slight increase in leukocyte adhesion. After ischemia, capillary perfusion rapidly recovered to about 50% and returned to near normal (90%) after 2 h. HTK at 22 degrees C did not affect the assessed microcirculation variables, whereas HTK at 4 degrees C reduced leukocyte rolling, but not adhesion. Therefore, microvascular function of HTK-perfused muscles was not better preserved during warm I/R than that of nonperfused muscles. Contrary to other preservation solutions, HTK perfusion in itself was not detrimental to the microcirculation.

A B S T R A C TThe purpose of this study was to assess the potential of preservation solutions for protecting skeletal muscle function during storage at 4 mC. The soleus and the cutaneus trunci (CT) from the rat were stored for 2, 8 or 16 h at 4 mC in University of Wisconsin solution (UW), HTK-Bretschneider solution (HTK) or Krebs-Henseleit solution (KH). After storage, muscles were stimulated electrically to analyse the isometric contractile properties, such as the maximum tetanic tension (P 0 ). Histological analysis was also performed. In separate experiments, the effect of the diffusion distance 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 values of 16 % and 69 % of control in UW and HTK respectively). At 16 h, the contractile properties of the CT (P 0 28 %) were again better preserved than those 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 showed increasing muscle fibre derangement with increasing storage time. For both muscles and all solutions, the threshold stimulus current increased with increasing storage time (control, 0.1 mA ; 16 h, 1.2 mA) and was strongly correlated with the deterioration in contractile properties. It is concluded that, at 4 mC, 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 for successful preservation of muscle function at 4 mC. The reduced function after 16 h of storage at 4 mC was caused by hypercontraction and necrosis of about 25 % of the muscle fibres, and by deterioration of the electrical component of excitation-contraction coupling of the remaining fibres. ! , maximum tetanic tension ; P t , maximum twitch tension ; 1\2RT, time from P t to half-maximum twitch tension ; TPT, time to P t ; dP\dt, maximum rate of tension development of a twitch ; UW, University of Wisconsin solution. Correspondence : Dr E. P. A. van der Heijden.functional outcome of any such reconstruction is, however, at best suboptimal, since missing tissues in the recipient area can only seldom be replaced by identical tissue. Additionally, morbidity of the site from which free flaps are taken can be quite substantial [2]. In the last decade, reconstructive surgeons have started