Tape Stripping Repetitions Reduce the Stratum Corneum Inversely
in Yucatan Miniature Swine
Horlen K.P.1, Brown L. 1, Hanks B.C.1, Wicks J.2, Liu J.1, Bouchard G.F.1
1
Sinclair Research Center, LLC;
2
Alizee Pathology, LLC
ABSTRACT
MATERIALS & METHODS (CONTINUED)
RESULTS (CONTINUED)
Miniature swine are a recognized predictive model for human drug candidate
dermatopharmacology studies. Tape stripping is a simple and effective method for
removing the stratum corneum (SC) and is commonly employed during in vivo
studies investigating the percutaneous penetration and disposition of topically
applied candidate drugs. The objective of this study was to assess the remaining
thickness of the SC following 0, 10, 20, 30, 40, and 50 repetitions of tape. Animals
were young adult, male Yucatan miniature swine weighing 33-36kg (N=3).
Animals were maintained under general anesthesia for the entire duration of the
procedures. Following clipping of the pelage over the dorsal lumbar and thoracic
areas, 6 sites, approximately 5cm by 5cm, were demarcated and skin was
stripped using U-Line 1.8mm clear acrylic adhesive tape applied with uniform, firm
pressure. Following tape applications, the center of the each test area was punch
biopsied (8mm) and samples fixed in 10% neutral buffered formalin. Samples
were processed, stained by H&E, and read under light microscopy. The results
showed an inverse pattern to the number of tape stripping repetitions. Fifty
passes were required to remove nearly all SC. These data demonstrate that
removal of the SC from skin is directly dependent stripping technique, and that up
to 50 repetitions might be necessary for adequate and consistent removal.
Six sites, approximately 5cm x 5cm were demarcated. Sites were spread equally
between the cranial and caudal test area margin and were equidistant from dorsal
midline. Sites were randomly assigned to one of six treatment groups to include 0,
10, 20, 30, 40, or 50 repetitions of tape stripping. The tape used was U-Line
1.8mm thick, 5cm wide clear acrylic adhesive tape (Pleasant Prairie, WI). Tape
was applied with firm, uniform pressure then rapidly removed with a single quick
action. The procedure was immediately repeated for each test site for the
determined number of repetitions.
Table 1 shows the number of layers of SC that remained for each treatment area
for each animal. The results showed an inverse relationship to the number to tape
stripping repetitions and the number of layers of SC remaining. Fifty passes
removed nearly all SC. Figure 1 shows that inconsistent removal of the SC was
observed across test sites. No immediately detectable underlying changes of the
epidermis or dermis were observed.
Following tape stripping, an 8mm full thickness skin punch biopsy was collected
from the center of each test area. Samples were fixed in 10% neutral buffered
formalin. Samples were then processed, sectioned at 5 μm, stained with H&E and
evaluated by light microscopy.
Animals were humanely euthanized by an intravenous overdose of sodium
pentobarbital following tape stripping procedures and prior to recovery from
anesthesia.
Figure 1. Photomicrograph of H&E skin sections (40X). The arrows point to areas
with scores of around 3, and the arrowheads point to areas with a score of 0 for
the left image and a score of 1 for the right image . Infoldings were considered at
least partially due to fixation artifact.
RESULTS
INTRODUCTION
The SC consists of nonviable cornified cells embedded in a lipid-rich intercellular
domain. Tape stripping is a useful method for removing the stratum corneum and
is commonly used in dermatological and pharmaceutical studies. Common
applications of tape stripping include: investigating percutaneous penetration and
disposition of topical applied drug, measuring the SC mass and thickness, and
disrupting of the skin barrier. (Choi MJ. 2004) The SC of a young adult Yucatan
male miniature swine averages 20-40 microns at the dorsal lumbar area (SRC
internal data, 2010) and consists of 11-15 layers of epidermis.
Table 1. Tape Stripping Sites & Stratum Corneum Present
Animal
2479
MATERIALS & METHODS
All research procedures were approved by the Sinclair Research Center LLC
Institutional Animal Care and Use Committee.
Three young adult, male, Yucatan miniature swine weighing 33-36kg were
selected for this study. Animals were anesthetized by administration of isoflurane
up to 5% in oxygen via nasal mask and then maintained under general anesthesia
by continued administration of isoflurane. Vital functions were routinely monitored
for the duration of the procedure to ensure animals remained in an acceptable
plane of anesthesia. Animals were placed in sternal recumbency and the pelage
over the dorsal lumbar and thoracic area from the wing of the ileum to the caudal
scapula was clipped and aseptically prepared.
2603
2609
No. of Treatments
SC Present
0
4
10
4
DISCUSSION
20
3
30
2-3
40
1-2
50
0-1
0
4
10
3-4
These data demonstrate that removal of the SC from skin is directly dependent
upon repetitions of the stripping procedure. Although 50 repetitions removed
nearly all SC consistent results could not be achieved within the individual test site
on each animal. The lack of continuous removal across the surface was likely a
result of normal undulations of the skin surface making exposure of the SC to the
tape inconsistent. The type and size of tape, pressure at application and removal,
and anatomical variances between sites and animals can all be important factors.
20
2-4
30
2
40
0-1
50
0-3
0
4
10
3-4
20
1-2
30
1-3
40
1-2
50
0
0 = No SC Present; 1 = 1-3 Layers;
2 = 4-6 Layers; 3 = 6-10 Layers;
4 = Full Layer (11-15 Layers)
REFERENCES
1. E Choi MJ, Zhai H, Maibach HI. Tape Stripping Method and Stratum Corneum.
In Dermatotoxicology. Ed. Zhai H, Maibach HI. 6th ed. Pgs. 533-548. 2004
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