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Effects of heat stimulation via microwave applicator on cartilage matrix gene and HSP70 expression in the rabbit knee joint
Author(s) -
Tonomura Hitoshi,
Takahashi Kenji A.,
Mazda Osam,
Arai Yuji,
ShinYa Masaharu,
Inoue Atsuo,
Honjo Kuniaki,
Hojo Tatsuya,
Imanishi Jiro,
Kubo Toshikazu
Publication year - 2008
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.20421
Subject(s) - hsp70 , stimulation , cartilage , extracellular matrix , gene expression , proteoglycan , heat shock protein , chemistry , in vivo , matrix (chemical analysis) , microbiology and biotechnology , messenger rna , anatomy , biology , endocrinology , biochemistry , gene , genetics , chromatography
The objective of this study was to investigate the effects of heat stimulation on the expression of extracellular matrix genes and heat‐shock protein 70 (HSP70) in rabbit articular cartilage in vivo. Heat stimulation was applied to the knee joints of Japanese white rabbits for 20 min using a microwave (MW) applicator (2.45‐GHz, 0–80 W). After 8–72 h, the articular cartilage was removed from the knee joints and proteins and total RNA were extracted. As controls, knee joints without heat stimulation were analyzed. The expression of HSP70 was confirmed by real‐time PCR and Western blotting. The expression of proteoglycan core protein (PG) and type II collagen (Col II) was quantified using real‐time PCR to assess cartilage matrix metabolism. Compared to controls, HSP70 expression was higher with more than 40 W of heat stimulation. The expression of PG and Col II mRNA was higher, with more than 20 W of heat stimulation and peaked with 40 W. When quercetin was used to inhibit the induction of HSP70 expression, PG mRNA expression did not increase. External MW application stimulated HSP70 expression in the articular cartilage in vivo. The expression of extracellular matrix genes was increased by appropriate heat stimulation. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:34–41, 2008