A comparison of the cutaneous microvascular properties of the Spontaneously Hypertensive rat and the Wistar-Kyoto rat

Marc S. Rendell, Mary F. Finnegan, Thomas Pisarri, James C. Healy, Anne Lind, Brian K. Milliken, David E. Finney, Robert F. Bonner

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The Spontaneously Hypertensive rat (SHR) and its non-hypertensive companion strain, the Wistar-Kyoto (WKY) rat, provide an excellent comparative model to permit study of the differential properties of cutaneous microvascular beds. We explored the possibility that chronically elevated vascular pressures in the SHR rat might affect the microvascular constitution of the skin. We measured skin blood flow at the back and at the paw of a group of 20-week-old WKY rats and a contrast group of SHR rats. We then performed skin biopsies at these two locations and used the NIH Image program to count and measure the size of capillaries, arterioles, and venules. We also determined microvascular density as percentage of total tissue area. At basal temperature, skin blood flow was similar in the two rat strains at both the back and paw. Heat induced vasodilatation resulted in a 50% increase in blood flow at the back, reaching the same level in the two rat groups. However, at the paw site, thermal stimulation resulted in significantly greater flow (39.3 ± 3.1 ml/100 gm tissue per min) in the SHR rats than the WKY rats (28.6 ± 1.9 ml/100 gm tissue per min, P <0.05). The ratio of systemic arterial pressure to skin blood flow was computed as an index of vascular resistance to flow. At basal temperature, this index was 50% greater for the SHR rats at both skin sites. At 44 °C, the resistance index decreased at both sites in both rat groups but was still ~ 50% higher at the back of the SHR than the WKY rats. In contrast, the resistance index at 44 °C at the paw site fell to the same level in both the SHR and WKY rats. There were twice as many capillaries at the back of the WKY rats than at the back of the SHR rats (9.2 ± 2.0 per mm 2 vs. 4.7 ± 1.2 per mm 2, P <0.05). Expressed as a percentage of total tissue area, the capillary density at the back in the WKY rats was 0.064 ± 0.010% as compared to 0.034 ± 0.008% in the SHR rats (P <0.05). There were five times more arterioles at the paw compared to the back in both rat groups with no significant difference between the groups. We measured the diameter of the lumen and the thickness of the wall of each arteriole and computed their ratio as an index of possible media hypertrophy. There were minimal differences seen in these parameters between the two rat groups at the back and paw sites. The venular density was significantly higher at the paw than at the back in both rat groups with no significant difference between them. Reduced capillary density at the back of the SHR rats may be a developmental adaptation to high blood pressure. Such a reduction in the pathways of blood flow may help account for increased flow resistance at that site, independent of arteriolar vasoconstriction.

Original languageEnglish
Pages (from-to)399-406
Number of pages8
JournalComparative biochemistry and physiology. Part A, Molecular & integrative physiology
Volume122
Issue number4
DOIs
StatePublished - Apr 1999

Fingerprint

Inbred WKY Rats
Inbred SHR Rats
Rats
Skin
Arterioles
Blood
Hot Temperature
Tissue
Temperature
Venules
Constitution and Bylaws
Vasoconstriction
Vasodilation
Vascular Resistance
Hypertrophy
Blood Vessels
Arterial Pressure

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Physiology

Cite this

A comparison of the cutaneous microvascular properties of the Spontaneously Hypertensive rat and the Wistar-Kyoto rat. / Rendell, Marc S.; Finnegan, Mary F.; Pisarri, Thomas; Healy, James C.; Lind, Anne; Milliken, Brian K.; Finney, David E.; Bonner, Robert F.

In: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology, Vol. 122, No. 4, 04.1999, p. 399-406.

Research output: Contribution to journalArticle

Rendell, Marc S. ; Finnegan, Mary F. ; Pisarri, Thomas ; Healy, James C. ; Lind, Anne ; Milliken, Brian K. ; Finney, David E. ; Bonner, Robert F. / A comparison of the cutaneous microvascular properties of the Spontaneously Hypertensive rat and the Wistar-Kyoto rat. In: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology. 1999 ; Vol. 122, No. 4. pp. 399-406.
@article{162e6aac91e545c3b4f11d6dfc2db65b,
title = "A comparison of the cutaneous microvascular properties of the Spontaneously Hypertensive rat and the Wistar-Kyoto rat",
abstract = "The Spontaneously Hypertensive rat (SHR) and its non-hypertensive companion strain, the Wistar-Kyoto (WKY) rat, provide an excellent comparative model to permit study of the differential properties of cutaneous microvascular beds. We explored the possibility that chronically elevated vascular pressures in the SHR rat might affect the microvascular constitution of the skin. We measured skin blood flow at the back and at the paw of a group of 20-week-old WKY rats and a contrast group of SHR rats. We then performed skin biopsies at these two locations and used the NIH Image program to count and measure the size of capillaries, arterioles, and venules. We also determined microvascular density as percentage of total tissue area. At basal temperature, skin blood flow was similar in the two rat strains at both the back and paw. Heat induced vasodilatation resulted in a 50{\%} increase in blood flow at the back, reaching the same level in the two rat groups. However, at the paw site, thermal stimulation resulted in significantly greater flow (39.3 ± 3.1 ml/100 gm tissue per min) in the SHR rats than the WKY rats (28.6 ± 1.9 ml/100 gm tissue per min, P <0.05). The ratio of systemic arterial pressure to skin blood flow was computed as an index of vascular resistance to flow. At basal temperature, this index was 50{\%} greater for the SHR rats at both skin sites. At 44 °C, the resistance index decreased at both sites in both rat groups but was still ~ 50{\%} higher at the back of the SHR than the WKY rats. In contrast, the resistance index at 44 °C at the paw site fell to the same level in both the SHR and WKY rats. There were twice as many capillaries at the back of the WKY rats than at the back of the SHR rats (9.2 ± 2.0 per mm 2 vs. 4.7 ± 1.2 per mm 2, P <0.05). Expressed as a percentage of total tissue area, the capillary density at the back in the WKY rats was 0.064 ± 0.010{\%} as compared to 0.034 ± 0.008{\%} in the SHR rats (P <0.05). There were five times more arterioles at the paw compared to the back in both rat groups with no significant difference between the groups. We measured the diameter of the lumen and the thickness of the wall of each arteriole and computed their ratio as an index of possible media hypertrophy. There were minimal differences seen in these parameters between the two rat groups at the back and paw sites. The venular density was significantly higher at the paw than at the back in both rat groups with no significant difference between them. Reduced capillary density at the back of the SHR rats may be a developmental adaptation to high blood pressure. Such a reduction in the pathways of blood flow may help account for increased flow resistance at that site, independent of arteriolar vasoconstriction.",
author = "Rendell, {Marc S.} and Finnegan, {Mary F.} and Thomas Pisarri and Healy, {James C.} and Anne Lind and Milliken, {Brian K.} and Finney, {David E.} and Bonner, {Robert F.}",
year = "1999",
month = "4",
doi = "10.1016/S1095-6433(99)00022-7",
language = "English",
volume = "122",
pages = "399--406",
journal = "Comparative Biochemistry and Physiology - A Physiology",
issn = "1095-6433",
publisher = "Elsevier Inc.",
number = "4",

}

TY - JOUR

T1 - A comparison of the cutaneous microvascular properties of the Spontaneously Hypertensive rat and the Wistar-Kyoto rat

AU - Rendell, Marc S.

AU - Finnegan, Mary F.

AU - Pisarri, Thomas

AU - Healy, James C.

AU - Lind, Anne

AU - Milliken, Brian K.

AU - Finney, David E.

AU - Bonner, Robert F.

PY - 1999/4

Y1 - 1999/4

N2 - The Spontaneously Hypertensive rat (SHR) and its non-hypertensive companion strain, the Wistar-Kyoto (WKY) rat, provide an excellent comparative model to permit study of the differential properties of cutaneous microvascular beds. We explored the possibility that chronically elevated vascular pressures in the SHR rat might affect the microvascular constitution of the skin. We measured skin blood flow at the back and at the paw of a group of 20-week-old WKY rats and a contrast group of SHR rats. We then performed skin biopsies at these two locations and used the NIH Image program to count and measure the size of capillaries, arterioles, and venules. We also determined microvascular density as percentage of total tissue area. At basal temperature, skin blood flow was similar in the two rat strains at both the back and paw. Heat induced vasodilatation resulted in a 50% increase in blood flow at the back, reaching the same level in the two rat groups. However, at the paw site, thermal stimulation resulted in significantly greater flow (39.3 ± 3.1 ml/100 gm tissue per min) in the SHR rats than the WKY rats (28.6 ± 1.9 ml/100 gm tissue per min, P <0.05). The ratio of systemic arterial pressure to skin blood flow was computed as an index of vascular resistance to flow. At basal temperature, this index was 50% greater for the SHR rats at both skin sites. At 44 °C, the resistance index decreased at both sites in both rat groups but was still ~ 50% higher at the back of the SHR than the WKY rats. In contrast, the resistance index at 44 °C at the paw site fell to the same level in both the SHR and WKY rats. There were twice as many capillaries at the back of the WKY rats than at the back of the SHR rats (9.2 ± 2.0 per mm 2 vs. 4.7 ± 1.2 per mm 2, P <0.05). Expressed as a percentage of total tissue area, the capillary density at the back in the WKY rats was 0.064 ± 0.010% as compared to 0.034 ± 0.008% in the SHR rats (P <0.05). There were five times more arterioles at the paw compared to the back in both rat groups with no significant difference between the groups. We measured the diameter of the lumen and the thickness of the wall of each arteriole and computed their ratio as an index of possible media hypertrophy. There were minimal differences seen in these parameters between the two rat groups at the back and paw sites. The venular density was significantly higher at the paw than at the back in both rat groups with no significant difference between them. Reduced capillary density at the back of the SHR rats may be a developmental adaptation to high blood pressure. Such a reduction in the pathways of blood flow may help account for increased flow resistance at that site, independent of arteriolar vasoconstriction.

AB - The Spontaneously Hypertensive rat (SHR) and its non-hypertensive companion strain, the Wistar-Kyoto (WKY) rat, provide an excellent comparative model to permit study of the differential properties of cutaneous microvascular beds. We explored the possibility that chronically elevated vascular pressures in the SHR rat might affect the microvascular constitution of the skin. We measured skin blood flow at the back and at the paw of a group of 20-week-old WKY rats and a contrast group of SHR rats. We then performed skin biopsies at these two locations and used the NIH Image program to count and measure the size of capillaries, arterioles, and venules. We also determined microvascular density as percentage of total tissue area. At basal temperature, skin blood flow was similar in the two rat strains at both the back and paw. Heat induced vasodilatation resulted in a 50% increase in blood flow at the back, reaching the same level in the two rat groups. However, at the paw site, thermal stimulation resulted in significantly greater flow (39.3 ± 3.1 ml/100 gm tissue per min) in the SHR rats than the WKY rats (28.6 ± 1.9 ml/100 gm tissue per min, P <0.05). The ratio of systemic arterial pressure to skin blood flow was computed as an index of vascular resistance to flow. At basal temperature, this index was 50% greater for the SHR rats at both skin sites. At 44 °C, the resistance index decreased at both sites in both rat groups but was still ~ 50% higher at the back of the SHR than the WKY rats. In contrast, the resistance index at 44 °C at the paw site fell to the same level in both the SHR and WKY rats. There were twice as many capillaries at the back of the WKY rats than at the back of the SHR rats (9.2 ± 2.0 per mm 2 vs. 4.7 ± 1.2 per mm 2, P <0.05). Expressed as a percentage of total tissue area, the capillary density at the back in the WKY rats was 0.064 ± 0.010% as compared to 0.034 ± 0.008% in the SHR rats (P <0.05). There were five times more arterioles at the paw compared to the back in both rat groups with no significant difference between the groups. We measured the diameter of the lumen and the thickness of the wall of each arteriole and computed their ratio as an index of possible media hypertrophy. There were minimal differences seen in these parameters between the two rat groups at the back and paw sites. The venular density was significantly higher at the paw than at the back in both rat groups with no significant difference between them. Reduced capillary density at the back of the SHR rats may be a developmental adaptation to high blood pressure. Such a reduction in the pathways of blood flow may help account for increased flow resistance at that site, independent of arteriolar vasoconstriction.

UR - http://www.scopus.com/inward/record.url?scp=0033067190&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033067190&partnerID=8YFLogxK

U2 - 10.1016/S1095-6433(99)00022-7

DO - 10.1016/S1095-6433(99)00022-7

M3 - Article

C2 - 10422258

AN - SCOPUS:0033067190

VL - 122

SP - 399

EP - 406

JO - Comparative Biochemistry and Physiology - A Physiology

JF - Comparative Biochemistry and Physiology - A Physiology

SN - 1095-6433

IS - 4

ER -