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Basic Research in Cardiology

, Volume 75, Issue 1, pp 244–252 | Cite as

Contracture type and fibrosis type of decreased myocardial distensibility. Different changes in elasticity of myocardium in hypoxia and hypertrophy

  • Ch. Holubarsch
Article

Summary

Resting length-tension relationships were measured in rat trabecular muscle strips under control (O2) and contracture (N2) conditions as well as in preparations of Goldblatt II (8-week stage) and control rats. For the evaluation of the diastolic elastic properties, diastolic stress at 1max, stress-strain relationships, the relation between tangent modulus\(\frac{{\Delta \sigma }}{{\Delta \varepsilon }}\) and stress σ, and the function ln stress σ=f (strain ɛ) were calculated and plotted. It was shown that the hypoxic contracture corresponds to the calcium-caffeine contracture—an experimental contracture model already investigated earlier. In contrast to these contracture-induced alterations, Goldblatt II hypertrophied myocardium corresponded to the fibrosis type. This type was already analyzed in an experimental model of myocardium-tendon tandem preparation. Additional investigations of hydroxyproline concentration of the same biological material showed in contrast to other studies that the collagen content may already be increased in this early stage of hypertrophy. Thus, altered distensibility of Goldblatt myocardium is certainly primarily due to increased connective tissue content.

Keywords

Hydroxyproline Muscle Strip Hypertrophied Myocardium Hydroxyproline Concentration Experimental Contracture 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Kontraktur- und Fibrosetyp bei verminderter myokardialer Dehnbarkeit. Unterschiedliche Veränderungen der Elastizität des Myokards bei Hypoxie und Hypertrophie

Zusammenfassung

Ruhe-Dehnungs-Beziehungen wurden an Hand von 8 Rattentrabekeln unter Kontroll- (O2) und Kontrakturbedingungen (N2) ebenso wie von Präparaten von 8 Goldblatt-Herzen der Ratte (8-Wochen-Stadium) ermittelt. Zur Beurteilung der diastolischen elastischen Eigenschaften wurde die diastolische Spannung bei 1max, “stress-strain”-Beziehungen, die Relation zwischen tangentiellem Elastizitätsmodul\(\frac{{\Delta \sigma }}{{\Delta \varepsilon }}\) und “stress” σ sowie die Funktion ln “stress” σ=f (strain ɛ) errechnet und dargestellt. — Es zeigte sich, daß die hypoxische Kontraktur bezüglich der elastischen Eigenschaften vollständig der Calcium-Coffein-Kontraktur entsprichteinem bereits früher von unserer Arbeitsgruppe untersuchten experimentellen Modell. Demgegenüber konnten auf der Grundlage der Elastizitätsberechnungen die Veränderungen bei der Goldblatt-Hypertrophie dem Fibrosetyp zugeordnet werden; auch dieser Typ der Elastizitätsänderung war in vorausgegangenen Experimenten an Tandempräparaten, bestehend aus Sehne und Myokard, bereits analysiert worden. Zusätzliche Hydroxyprolin-Bestimmungen an demselben Experimentiergut zeigten im Gegensatz zu früheren Befunden, daß der Kollagengehalt bereits im 8-Wochen-Stadium der Goldblatt-Hypertrophie gesteigert sein kann, und waren mit den mechanischen Parametern voll vereinbar.

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Copyright information

© Dr. Dietrich Steinkopff Verlag 1980

Authors and Affiliations

  • Ch. Holubarsch
    • 1
  1. 1.Physiologisches Institut IIUniversität TübingenTübingen

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