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Type: Artigo de periódico
Title: Low-intensity Ultrasound Increases Fak, Erk-1/2, And Irs-1 Expression Of Intact Rat Bones In A Noncumulative Manner.
Author: de Gusmão, Carlos Vinícius Buarque
Pauli, José Rodrigo
Saad, Mario José Abdalla
Alves, José Marcos
Belangero, William Dias
Abstract: Low-intensity pulsed ultrasound stimulation (LIPUS) reportedly increases osteogenesis in fracture models but fails in intact bone, suggesting LIPUS does not act on mechanotransduction and growth factor pathways of intact bone. We asked whether daily 20-minute LIPUS applied to intact tibias would act on bone proteins involved in mechanotransduction (focal adhesion kinase [FAK], and extracellular signal-regulated kinase-1/2 [ERK-1/2]), and growth factor signaling (insulin receptor substrate-1 [IRS-1]) pathways at 7, 14, and 21 days of treatment. Immunoblotting was performed to detect FAK, ERK-1/2, and IRS-1 expression and activation from the stimulated intact tibias at 7, 14, and 21 days of daily 20-minute LIPUS. LIPUS increased FAK expression (at 7 days), ERK-1/2 (at 14 days), and IRS-1 (at 7 days), but expression decreased 7 days later, indicating a noncumulative effect of LIPUS. As only FAK expression was detected at 21 days, these observations suggest LIPUS influences nuclear reactions that may be modulated by a major cellular mechanism preferentially inhibiting IRS-1 expression and not FAK expression. Increased ERK-1/2 expression at 14 days suggests the differing mechanisms for promoting ERK-1/2, FAK, and IRS-1 syntheses. IRS-1 expression behaved similarly to FAK expression; therefore, LIPUS may modulate growth factor pathways. LIPUS increased sustained FAK and ERK-1/2 activation, but not IRS-1, suggesting sustained ERK-1/2 activation is not the result of mechanically induced growth factor activation. LIPUS acts on mechanotransduction and growth factor pathways in intact bone in a noncumulative manner. Clinical relevance These data suggest LIPUS applied to intact bone acts on proteins involved in osteogenesis.
Subject: Animals
Extracellular Signal-regulated Map Kinases
Focal Adhesion Protein-tyrosine Kinases
Insulin Receptor Substrate Proteins
Mechanotransduction, Cellular
Mitogen-activated Protein Kinase 1
Mitogen-activated Protein Kinase 3
Rats, Inbred Strains
Ultrasonic Therapy
Citation: Clinical Orthopaedics And Related Research. v. 468, n. 4, p. 1149-56, 2010-Apr.
Rights: fechado
Identifier DOI: 10.1007/s11999-009-1146-6
Date Issue: 2010
Appears in Collections:Unicamp - Artigos e Outros Documentos

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