title: Effects of heat stimulation via microwave applicator on cartilage matrix gene and HSP70 expression in the rabbit knee joint.
abstract: 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.
authors.affiliation: Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Tonomura
authors.forename: Kenji A
authors.initials: KA
authors.lastname: Takahashi
authors.forename: Osam
authors.initials: O
authors.lastname: Mazda
authors.forename: Yuji
authors.initials: Y
authors.lastname: Arai
authors.forename: Masaharu
authors.initials: M
authors.lastname: Shin-Ya
authors.forename: Atsuo
authors.initials: A
authors.lastname: Inoue
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Honjo
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hojo
authors.forename: Jiro
authors.initials: J
authors.lastname: Imanishi
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000818:Animals; D002356:Cartilage / Q000502:physiology*; D024043:Collagen Type II / Q000235:genetics; D005109:Extracellular Matrix / Q000502:physiology; D016326:Extracellular Matrix Proteins / Q000235:genetics; D015870:Gene Expression; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D006358:Hot Temperature; D007036:Hypothermia, Induced / Q000379:methods*; D008872:Microwaves / Q000627:therapeutic use*; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000628:therapy*; D011509:Proteoglycans / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits
chemical_list: D024043:Collagen Type II; D016326:Extracellular Matrix Proteins; D018840:HSP70 Heat-Shock Proteins; D011509:Proteoglycans; D012333:RNA, Messenger