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In This Article

  • Summary
  • Abstract
  • Introduction
  • Protocol
  • Representative Results
  • Discussion
  • Acknowledgements
  • Materials
  • References
  • Reprints and Permissions

Summary

The protocol describes the use of wire myography to evaluate the transmural isometric tension of mesenteric arteries isolated from mice, with special consideration of the modulation by factors released from endothelial cells and perivascular adipose tissues.

Abstract

Altered vascular tone responsiveness to pathophysiological stimuli contributes to the development of a wide range of cardiovascular and metabolic diseases. Endothelial dysfunction represents a major culprit for the reduced vasodilatation and enhanced vasoconstriction of arteries. Adipose (fat) tissues surrounding the arteries play important roles in the regulation of endothelium-dependent relaxation and/or contraction of the vascular smooth muscle cells. The cross-talks between the endothelium and perivascular adipose tissues can be assessed ex vivo using mounted blood vessels by a wire myography system. However, optimal settings should be established for arteries derived from animals of different species, ages, genetic backgrounds and/or pathophysiological conditions.

Introduction

Dilatations and constrictions of arteries are achieved by relaxations and contractions, respectively, of their vascular smooth muscle cells. Changes in vascular responsiveness of small arteries contribute to the homeostatic regulation of arterial blood pressure by autonomic nerves and hormones present in the blood (e.g., catecholamines, angiotensin II, serotonin, vasopressin). At the local level, the vascular responses of smooth muscle cells are modulated by signals from both the endothelial cells of the intima and the adipose tissue surrounding the arteries (Figure 1).

The endothelium is not only a passive bar....

Protocol

All animals used for the following study were provided by the Laboratory Animal Unit of the Faculty of Medicine, The University of Hong Kong. Ethical approval was obtained from the departmental Committee on Use of Laboratory Animals for Teaching and Research (CULATR, no.: 4085-16).

1. Preparations

  1. Preparation of drugs
    1. Store drugs appropriately as stated in the Material Safety Data Sheet (MSDS) immediately after receiving them. Dissolve the drugs in powd.......

Representative Results

Examination of the length/tension relationships to obtain the normalization factor k

The amount of stretch applied to a vessel segment influences the extent of the actin-myosin interaction and hence the maximal active force developed. Thus, for every type of blood vessel, determining the amount of stretch needed for maximal active force is required for proper myography studies. Here, normalization of t.......

Discussion

Apart from the endothelial cells, signals derived from PVAT play an important role in the regulation of smooth muscle tone reactivity30. Healthy PVAT releases NO and anti-inflammatory adiponectin to exert an anti-contractile effect on arteries, which is lost under pathological conditions such as obesity and metabolic syndrome31,32. In disease states, PVAT contributes to the development of endothelial dysfunction and other cardiovascular ab.......

Acknowledgements

This work was financially support by the grants from Research Grant Council of Hong Kong [17124718 and 17121714], Hong Kong Health and Medical Research Fund [13142651 and 13142641], Collaborative Research Fund of Hong Kong [C7055-14G], and the National Basic Research Program of China [973 Program 2015CB553603].

....

Materials

NameCompanyCatalog NumberComments
AcetylcholineSigma-AldrichA6625Stock concentration: 10-1 M
Working concentration: 10-10 to 10-5 M
L-NAME (Nω-nitro-L-arginine methyl ester)Sigma-AldrichN5751Stock concentration: 3 x 10-2 M
Working concentration: 10-4 M
PhenylephrineSigma-AldrichP6126Stock concentration: 10-2 M
Working concentration: 10-10 to 10-5 M
U46619 (9,11-dideoxy-9α,11αmethanoepoxy prostaglandin F2α)EnzoBML-PG023-0001Stock concentration: 10-5 M
Working concentration: 1-3 x 10-8 M
Multiwire myographDanish MyoTechnology (DMT)620M
PowerLab 4/26ADInstrumentsML848
Labchart7ADInstruments-
Adipo-SIRT1 wild type miceLaboratory Animal Unit, The University of Hong KongCULATR NO.: 4085-16
Silicon-coated Petri dishesDanish MyoTechnology (DMT)
Tungsten wiresDanish MyoTechnology (DMT)300331
Surgical tools

References

  1. Furchgott, R. F., Zawadzki, J. V. The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. Nature. 288 (5789), 373-376 (1980).
  2. Furchgott, R. F., Vanhoutte, P. M.

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Vascular ToneMesenteric ArteriesPerivascular Adipose TissuesIsometric ConditionVascular ResponsivenessAdipose Tissue DysfunctionHypertensionCardiovascular ComplicationsMyographNormalizationPassive StretchWall TensionActive ForcePotassium Chloride

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