Comparative examination of subcutaneous tissue reaction to high molecular materials in medical use

2) Kawakami T_Umbruchvorlage 03.06.11 17:13 Seite 249
June 21, 2011 Eu Ro PEa n Jo u R n a l o f MEd IC a l RE SEa RCH 249
Eur J Med Res (2011) 16: 249-252 © I. Holzapfel Publishers 2011
Co MPa Ra t Iv E Ex a MIn a t Io n o f Su b Cu t a n Eo u S t ISSu E REa Ct Io n t o
HIg H Mo l ECu l a R Ma t ERIa l S In MEd ICa l u SE
1 2 3 2M. t omida , K. n akano , S. Matsuura , t . Kawakami
1d epartment of o ral Physiology, Matsumoto d ental u niversity School of d entistry, Shiojiri, Japan
2Hard t issue Pathology u nit, Matsumoto d ental u niversity Institute for o ral Science, Shiojiri, Japan
3d epartment of b iology, Matsumoto d ental u niversity School of d entistry, Shiojiri, Japan
Abstract PE, 0.79mm; and f E, 0.94mm. t he materials were
Polypropylene (PP), Polyethylene (PE) and polytetra- then disinfected by autoclave treatment.
fluoroethylene (f E) are high molecular materials in
medical use. t hey are also used as the negative control a n IMa l S
materials for ISo 10993-6 international standard
biological evaluation of medical devices. We examined tis- a total of 18 male 9-week-old ddY mice weighing
sue reactions to these materials embedded subcuta- about 35g (30-40g) each were purchased from Japan
neously in the dorsal area of male ddY mice. o ne Sl C Inc. (Hamamatsu, Japan). t he animals were kept
week and 12 weeks after embedding, the tissue sur- in plastic cages with a floor mat (Paper Clean: Peparlet
rounding the embedding site was removed and then Co., l td., Shizuoka, Japan) under controlled
air-condihistopathological examination was performed. o ur re- tioned room with water and solid diet (Picolab Rodent
sults demonstrate that the basic histopathological reac- d iet 20: Japan Sl C Inc., Hamamatsu, Japan) during
tion is the formation of fibrous capsule consisting of the experimental periods.
granulation tissue around the embedded materials. t he Matsumoto d ental u niversity Committee for
based on our results, we believe that the high molecu- a nimal Experimentation approved the study.
lar materials such as, PP, PE and f E, can be
considered for medical use as a biomaterials within the body. MEt Ho d S
Key words: t issue reaction; Histopathological evalua- Prior to the examination, inhalation anesthesia was
tion; High molecular material used with isoflurane (Isoflu: d ainippon Sumitomo
Pharma Co., o saka, Japan) and gas-air mixture (4.0%
In t Ro d u Ct Io n concentration). Immediately after the dorsal areas of
the mice were disinfected with 70% ethanol, the
incibecause high molecular polymer is used as a material sions were made, and the materials were injected
subin vivo, it should be evaluated for safety according to cutaneously into the connective tissues. t he skin
surISo standard 10993-6 [1, 2]. Polypropylene (PP), Poly- face at the incision sites was sutured using suture
ethylene (PE) and polytetrafluoroethylene (f E) are string. t he site was marked every 2 weeks until the
fihigh molecular materials in medical use, although the nal examination period at 12 weeks.
tissue reaction in a single material is not examined. a t 1 week and 12 weeks after the injection, 3 mice
t hey are also used as the negative control materials from each group were anaesthetized with isoflurane
for ISo 10993-6 international standard biological eval- and gas-air mixture, and the tissues surrounding the
uation of medical devices. In the present investigation, injection sites were excised. t he excised tissues were
we examine the local effects after implantation of the immediately fixed in 4% paraformaldehyde/0.5M
above-mentioned materials. t he data led us to believe phosphate buffered solution, embedded in paraffin,
that many researchers can know the tissue reactions to and sections prepared.
these biomaterials itself. t his means next step of de- t he tissue sections were stained with hematoxylin
veloping new biomaterials. and eosin and examined by light microscopy for
histopathological changes. We followed the
InternaMa t ERIa l S a n d MEt Ho d S tional o rganization for Standardization (ISo )
guidelines for evaluating the local effects of injection mate-Ma t ERIa l S
rials [2].
t he materials to be examined include 1)
Polypropylene (PP: Prime Polypro; Prime Polymer Co., l td., RESu l t S
t okyo), 2) Polyethylene (PE: HI-ZEx , Prime Polymer Po l YPRo PYl En E: PP
Co., l td., t okyo) and 3) Polytetrafluoroethylene (f E:
t eflonRt f E; d u Pont-Mitsui f luorochemicals Co., Histopathological examination of the Polypropylene
l td., t okyo), in discoids 6mm in diameter. Materials group, 1-week-specimens, showed granulation tissue
were prepared in the following thickness: PP, 0.54mm; proliferation around the embedded material (f ig. 1,2) Kawakami T_Umbruchvorlage 03.06.11 17:13 Seite 250
250 Eu Ro PEa n Jo u Rn a l o f MEd ICa l RESEa RCH June 21, 2011
Fig. 1. PP-1: g ranulation tissue formation surrounding the material PP. (PP, 1-wk-specimen, x100); PP-12: g ranulation tissue
with some necrotic tissue foci and inflammatory cell infiltration. (PP, 12-wk-specimen, x100); PE-1: Proliferation of scattered
granulation tissue around the embedded material PE. (PE, 1-wk-specimen, x100); PE-12: t he granulation tissue changed to
fibrous tissue. (PE, 12-wk-specime, x100); f E-1: t hin layered fibrous capsule tissue around the material f E. (f E, 1-wk-specimen,
x100); f E-12: t hin fibrous layered tissue. (f E, 12-wk-specimen, x100). M: Embedded material.
PP-1). t he material attached to the surface area of the flammatory cell infiltration in the tissue; thus, the
tisgranulation tissue was stained well by eosin, showing sue began to change to fibrous tissue.
necrotic changes. Just under the region, inflammatory
cell-rich granulation tissue was observed. t he enlarged Po l YEt HYl En E: PE
view showed there were some inflammatory cells and
a few fibroblasts in the surface eosin-stained region. In 1-week specimens, proliferation of scattered
granua fter 12 weeks, a thin fibrous tissue capsule tissue lation tissue was observed around the embedded
materwas formed (f ig.1, PP-12). t here was almost no in- ial (f ig. 1, PE-1). In the scattered granulation tissues,2) Kawakami T_Umbruchvorlage 03.06.11 17:13 Seite 251
June 21, 2011 Eu Ro PEa n Jo u Rn a l o f MEd ICa l RESEa RCH 251
there was some lymphocyte-rich inflammatory cell infil- medical use as biomaterials within the body. a s our
tration as well as capillaries showing hyperemia. t he study complied with the ISo ’s biological Evaluation
en larged view showed that there were some eosin uni- of Medical d evices Standard Part 12, we have
approformly-stained region, which suggested necrotic change. priately evaluated the histopathological safety of using
In 12-week specimen observations, the inflammato- PP, PE and f E subcutaneously.
ry cell infiltration had almost disappeared in the
prolifAcknowledgments: t he authors thank Professor d M Carlsonerated granulation tissues. t he granulation tissues
of Matsumoto d ental u niversity, for his critical reading ofchanged to fibrous tissues (f ig. 1, PE-12). a ttached
the manuscript.the surface of the determination edge of the
embedded material was a thin fibrous tissue layer, which
covered the scattered connective tissues. Some capillaries
REf EREn CESshowing hyperemia were observed in the tissues.
1. u pman PJ: ISo 10993-6: t est for local effects after
implantation. bo n EZone 2006; 5(1): 50-52.Po l Yt Et Ra f l u o Ro Et HYl En E ：f E
2. International o rganization for Standardization (ISo ):
biological Evaluation of Medical d evices –Part 1: Evalua-In histopathological observations of 1-week
specition and testing, ISo 10993-1:2003 (E). g eneva, Switzer-mens, we note that a thin layered fibrous capsule tissue
land. 2003.formed around the embedded material (f ig. 1, f E-1).
3. Rabah d M, beginl R, Zahran a and Corcos J. t issue
ret he fibrous capsule was slightly thick at the determi- actions of the rabit urinarybladder to cadaveric human
nation edge of the material. t he thin fibrous capsule fascia lata and polypropylene surgical mesh. Can J u rol
tissue had almost no inflammatory cell infiltrations. 2004; 11: 2344-2349.
In 12-week histopathological specimens, the fibrous 4. Esenyel CZ, d emirhan M, Kilicoglu o , a danir o , bilgic
tissue gradually changed to a thiner fibrous layered tis- b, g uzel o and o zsoy S. Evaluation of soft tissue
reactions to three nonabsorbable suture materials in a rabbitsue (f ig. 1, f E-12). t he enlarged view showed more
model. a cta o rthop t raumatol t uc 2009; 43: 366-372.clearly the state of the fibrous tissue.
5. Saito t , t akemoto M, f ukuda a , Kuroda Y, f ujibayashi
S, n eo M, Honjoh d , Hiraide t , Kizuki t , Kokubo td ISCu SSIo n
and n akamura t . Effect of titania-based surface
modification of polyethylene terephthalate on bone-implant
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a ccording to the data, their safety has been con- nonporous polytetrafluoroethylene prosthesis in
combifirmed, although there are some associated inflamma- nation with polypropylene prosthetic abdominal wall
implants in prevention of peritoneal abhensions. J biomedtory reaction