title: Caspase 3 silencing inhibits biomechanical overload-induced intervertebral disk degeneration.
abstract: Intervertebral disk (IVD) degeneration causes debilitating low back pain in much of the worldwide population. No efficient treatment exists because of an unclear pathogenesis. One characteristic event early in such degeneration is the apoptosis of nucleus pulposus (NP) cells embedded in IVDs. Excessive biomechanical loading may also be a major etiology of IVD degeneration. The present study used in vitro and in vivo models of compressive loading to elucidate the underlying mechanism of IVD degeneration. In addition, we investigated whether the inhibition of apoptosis is a potential clinical therapeutic strategy for the treatment of IVD degeneration induced by biomechanical stress. A TUNEL assay showed that NP cell-agarose three-dimensional composite cultures subjected to uniaxial, unconfined, static, compressive loading exhibited a time-dependent increase in apoptosis. Western blot analysis revealed the up-regulation of several extracellular matrix-degrading enzymes and down-regulation of tissue inhibitor of metalloproteinase 1. These responses to compressive loading were all significantly inhibited by caspase 3 siRNA. In the in vivo model of compressive loading-induced IVD degeneration, a single local injection of caspase 3 siRNA significantly inhibited IVD degeneration by magnetic resonance imaging, histological findings, IHC, and TUNEL assay. The present study suggests that caspase 3 siRNA attenuates overload-induced IVD degeneration by inhibiting NP cell apoptosis and the expression of matrix-degrading enzymes.
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Yamada
authors.affiliation: Department of Advanced Medicine for Spine and Spinal Cord Disorders, Hokkaido University Graduate School of Medicine, Hokkaido, Japan. Electronic address: hidekisudo@yahoo.co.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Sudo
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Iwasaki
authors.affiliation: Division of Advanced Interdisciplinary Science, Faculty of Advance Life Science, Hokkaido University, Hokkaido, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Sasaki
authors.affiliation: Division of Infection and Immunity, Hokkaido University Research Center for Zoonosis Control, Sapporo, Hokkaido, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Higashi
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kameda
authors.affiliation: Department of Advanced Medicine for Spine and Spinal Cord Disorders, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Ito
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Takahata
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Kuniyoshi
authors.initials: K
authors.lastname: Abumi
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Minami
authors.affiliation: Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Hokkaido, Japan.
authors.forename: Norimasa
authors.initials: N
authors.lastname: Iwasaki
mesh_terms: D000818:Animals; D017209:Apoptosis; D001696:Biomechanical Phenomena; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D015536:Down-Regulation; D005109:Extracellular Matrix / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D020868:Gene Silencing; D006801:Humans; D007403:Intervertebral Disc / Q000378:metabolism / Q000473:pathology; D055959:Intervertebral Disc Degeneration / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D008954:Models, Biological; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000378:metabolism; D011817:Rabbits; D015398:Signal Transduction; D015854:Up-Regulation; D016474:Weight-Bearing
chemical_list: D034741:RNA, Small Interfering; D053148:Caspase 3