Post-operative effects on insulin resistance and specific tension of single skeletal muscle fibres

• Surgery and accidental trauma are associated with a transient period of insulin resistance, substrate catabolism and muscle weakness. In the present study, we evaluated the changes in the force-generating capacity of chemically skinned single muscle fibresfollowing abdominal surgery. Biopsies of the m. vastus lateralis were obtained in three patients 1 day before and 3 or 6 days after surgery. Part of the biopsy was frozen for histochemical analysis of the fibre cross-sectional area (FCSA) and myofibrillar protein content, and another part was used for single-fibre contractile measurements. All patients developed insulin resistance following surgery. The maximum velocity of unloaded shortening of single muscle fibres did not change following surgery. The FCSA did not decrease after surgery, as determined either from histochemical sections or from singlefibres measured at a fixed sarcomere length of 2.76+/-0.09 microm (mean+/-S.D.). Further, the force-generating capacity of the single fibres, measured as maximal Ca(2+)-activated force (P(0)) or as P(0) normalized to FCSA (specific tension), remained unchanged, as did the myofibrillar protein content of the muscle. In conclusion, the muscle weakness associated with post-operative insulin resistance is not related to a decreased specifictension or a loss of myofibrillar proteins. Other potential cellular mechanisms underlying post-operative weakness are discussed.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Physiology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Kirurgi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Surgery (hsv//eng)

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