Quantification of microvasculature in the canine spinal cord
Article first published online: 8 FEB 2005
Copyright © 1981 Wiley-Liss, Inc.
The Anatomical Record
Volume 200, Issue 1, pages 103–113, May 1981
How to Cite
Ireland, W. P., Fletcher, T. F. and Bingham, C. (1981), Quantification of microvasculature in the canine spinal cord. Anat. Rec., 200: 103–113. doi: 10.1002/ar.1092000110
- Issue published online: 8 FEB 2005
- Article first published online: 8 FEB 2005
- Manuscript Accepted: 24 OCT 1980
- Manuscript Received: 30 SEP 1980
Capillary density and capillary orientation in canine spinal cords were estimated by calculating actual lengths, surfaces, and volumes of capillary segments in tissue sections. Transverse, sagittal, and frontal section planes were sampled from dorsal, ventral, and lateral funiculi and from dorsal and ventral gray horns of spinal segments C3, T6, and L3 from three dogs. Capillaries were defined as vessels less than 10 μm in diameter. Electron microscopy of 104 such vessels revealed no muscle coat but collagen fibrils between endothelium and astrocyte process in 68% of the white matter capillaries and 16% of those in gray matter. Capillary diameter was significantly different among regions in some cases, but consistent patterns of variation were not found. Capillary density was four to five times greater in gray matter than in white matter. Capillary density differed significantly among the same-size dogs, but within dogs, density was similar among segments and within gray matter and white matter regions. In 62% of the transverse sections, capillary orientation was significant but mean direction was variable. Significant capillary orientation was found in 89% of the sagittal and frontal sections, and the mean direction was always along the craniocaudal axis of the spinal cord. The craniocaudal orientation was significant in 96% of the white matter sections and 78% of the gray sections, and in 97% of the cervical and thoracic sections but only 73% of the lumbar sagittal and frontal sections.
Because capillary orientation is neither isotropic nor regular, unbiased, lowvariance estimates of capillary density cannot be expected without resorting to excessive sampling. An efficient method of quantifying spinal capillaries for comparative purposes by counting number of profiles per unit area is recommended.