There are 5 distinct aspects to this study. (i) Two histological stains for
collagen were compared against each other for the first time, namely Herovici's technique and picrosirius-polarization. (ii) Skin samples from
embalmed cadaveric tissue from human cadavers were compared against
samples taken from surgical patients. (iii) Skin samples were studied from
different regions of the body to assess if dermal structure correlates with
scarring potential. (iv) Skin samples were sectioned in a plane parallel to the
epidermis to gain further insight into dermal structure. (v) A novel basement
membrane stain was produced.
Type I and type III collagen are important structural constituents of dermis
and play a crucial role in wound healing. Only two traditional histological
methods are thought to differentiate between them, so avoiding the need for
antibodies. These were compared against each other for the first time in
order to establish differences in image quality and discrimination between
Type I and type III collagen. Neither technique requires antibodies, however
picrosirius requires polarisation microscopy.
to result in a clearer, consistently reproducible collagen staining pattern than
the picrosirius method and more importantly did not require elaborate
apparatus to analyze. Additionally other cellular elements were visible.
Skin samples for research are often obtained from surgical excision. This
clearly limits which tissues are available for comparative study to those areas operated on. Studying samples from embalmed medical school cadavers
has the great advantage of studying areas of the body not routinely available
from common surgical procedures. It was therefore desirable to assess
whether embalmed cadaveric tissues exhibited different properties by virtue
of their age and the embalming process compared to fresh surgical
specimens, in order to give confidence that studies utilising the former would
be equally valid. To test this, 58 skin samples from embalmed medical
school cadavers were compared to skin samples from 38 fresh operative
specimens. The levels of tissue preservation and processing artefacts were
similar in both groups. Embalmed medical school cadavers clearly offer an
opportunity to study tissue areas not routinely available during surgery. This
is the first time such a comparison has been made.
Many things will affect the final appearance of the scar, but the single most
important determinant is the body region affected. The most common areas
for unfavourable scarring, specifically keloid or hypertrophic scarring have
been shown to be the ear, deltoid and sternal areas. To test the hypothesis
that there is no difference in histological structure of skin that correlates to
body region, comparative histology was undertaken exploring the regional
variations of skin characteristics in 58 cadaveric samples. Closely
comparable samples were taken from the deltoid (9), abdomen (13), sternum
(10), post-auricular (5), earlobe (12) and eyelid (9). Epidermal thickness,
epidermal appendage density and collagen fibre orientation were examined
and qualitative structural differences were assessed for each region Skin samples were then grouped by both topographical location of the body
and scarring potential. Skin samples exhibited qualitative and quantifiable
regional variations in the characteristics studied. Epidermal thickness and
appendage counts did not correlate with scarring potential. Both however
were statistically significantly higher in skin sampled from the head compared
to the trunk. Bundles of collagen fibres in the reticular dermis were grouped
according to their orientation in relation to the coronal plane; either parallel,
oblique or perpendicular. The ratio of oblique to parallel fibres was
statistically significantly higher in body areas with poorer scarring prognosis.
This corresponds to a more disorganised arrangement of collagen fibres in
these areas.
Further qualitative understanding of dermal collagen fibres came from
perpendicular to conventional histological samples. This new method stained basement membranes purple, cytoplasm was stained greenish-brown and nuclei dark brown. Collagen fibres were either thin and blue or thick and green. This
method was compared to PAS staining and although required more
preparative steps allows greater identification of other cellular structures.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/5711 |
| Date | January 2010 |
| Creators | Asaad, Kamil |
| Contributors | Naylor, Ian |
| Publisher | University of Bradford, School of Life Sciences |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, MPhil |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
Page generated in 0.0021 seconds