Biorheology - Volume 43, issue 3-4

Authors: Kopakkala-Tani, Milla | Leskinen, Jarkko J. | Karjalainen, Hannu M. | Karjalainen, Tero | Hynynen, Kullervo | Töyräs, Juha | Jurvelin, Jukka S. | Lammi, Mikko J.

Article Type: Research Article

Abstract: Mechanical forces can stimulate the production of extracellular matrix molecules. We tested the efficacy of ultrasound to increase proteoglycan synthesis in bovine primary chondrocytes. The ultrasound-induced temperature rise was measured and its contribution to the synthesis was investigated using bare heat stimulus. Chondrocytes from five cellular isolations were exposed in triplicate to ultrasound (1 MHz, duty cycle 20%, pulse repetition frequency 1 kHz) at average intensity of 580 mW/cm2 for 10 minutes daily for 1–5 days. Temperature evolution was recorded during the sonication and corresponding temperature history was created using a controllable water bath. This exposure profile was used …in 10-minute-long heat treatments of chondrocytes. Heat shock protein 70 (Hsp70) levels after one-time treatment to ultrasound and heat was analyzed by Western blotting, and proteoglycan synthesis was evaluated by 35 S-sulfate incorporation. Ultrasound treatment did not induce Hsp70, while heat treatment caused a slight heat stress response. Proteoglycan synthesis was increased approximately 2-fold after 3–4 daily ultrasound stimulations, and remained at that level until day 5 in responsive cell isolates. However, chondrocytes from one donor cell isolation out of five remained non-responsive. Heat treatment alone did not increase proteoglycan synthesis. In conclusion, our study confirms that pulsed ultrasound stimulation can induce proteoglycan synthesis in chondrocytes. Show more

Keywords: Ultrasound treatment, heat, proteoglycans, chondrocyte

Citation: Biorheology, vol. 43, no. 3-4, pp. 271-282, 2006

Authors: Sivan, S. | Neidlinger-Wilke, C. | Würtz, K. | Maroudas, A. | Urban, J.P.G.

Article Type: Research Article

Abstract: The intervertebral discs are large cartilaginous structures situated between the vertebral bodies, occupying around one third of the length of the spinal column. They act as the joints of the spine and carry mechanical load arising from body weight and muscle activity. Loads change with every alteration of posture and activity and the discs thus undergo a diurnal loading pattern with high loads on the discs during the day's activity and low loads on it at night during rest. As the disc is an osmotic system, around 25% of the disc's fluid is expressed and re-imbibed during each diurnal cycle …with consequent changes in the osmotic environment of the disc cells. Here, present information on the effect of osmotic changes in disc cell metabolism is reviewed; results indicate that prevailing osmolarity is a powerful regulator of disc cell activity. Show more

Citation: Biorheology, vol. 43, no. 3-4, pp. 283-291, 2006

Authors: Marques, Mara Rúbia | Hajjar, Denise | Oliveira Crema, Virgínia | Kimura, Edna Teruko | Santos, Marinilce Fagundes

Article Type: Research Article

Abstract: We have previously shown that a mandibular propulsive appliance (MPA) stimulates cell proliferation and the synthesis of growth factors in the rat condylar cartilage. The aim of this study was to evaluate the effects of a MPA in the distribution of the integrin subunits α1 and α2 in this cartilage. Twenty eight days-old male Wistar rats were divided into treated (T) and age-matched control groups (C). Treated rats wore the appliance during 3, 5, 7, 9, 11, 15, 20, 30 and 35 days. The condyles were fixed, decalcified and paraffin-embedded. The distribution of α1 and α2 was studied by immunohistochemistry. …Alpha1 distribution was uniform along the cartilage, increasing in 48 days-old rats (C20). Treated animals anticipated this increase to the age of 36 days (T9). The number of α2-positive cells was increased in C9 in the anterior condylar region, in C9 and C20 in the middle region and showed no differences in the posterior region. The MPA apparently abolished all variations, leading to a single increase at T30 in all regions. These results suggest that integrins containing the α1 and α2 subunits are modulated by forces promoted by the MPA, participating of the biological response to this therapy. Show more

Keywords: Functional orthopedics, condyle, alpha1, alpha2, integrin

Citation: Biorheology, vol. 43, no. 3-4, pp. 293-302, 2006

Authors: Benallaoua, Mourad | Richette, Pascal | François, Mathias | Tsagris, Lydia | Revel, Michel | Corvol, Maité | Poiraudeau, Serge | Savouret, Jean-François | Rannou, François

Article Type: Research Article

Abstract: Proteoglycan production is one of the major extracellular matrix components implicated in the dynamic process of intervertebral disc degeneration. Mechanical stress is an important modulator of the degeneration, but the underlying molecular mechanism at the proteoglycan level remains unclear. The aim of this work was to study the regulation of proteoglycan production by cyclic tensile stretch applied to intervertebral disc annulus fibrosus cells. Matrix metalloproteinases do not seem to be implicated in the regulation of proteoglycan production. By contrast, nitrite oxide production is induced by cyclic tensile stretch, in a time, intensity, and frequency dependant manner. Using a non-specific nitric …oxide synthases inhibitor [NG -methyl-L-arginine (L-NMA)], we suppress totally the inhibition of proteoglycan production induced by cyclic tensile stretch suggesting the implication of nitric oxide synthases in the observed phenomenon. Introducing the transcriptional inhibitor 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole or a more specific inhibitor of nitric oxide synthases II [N-iminoethyl-L-lysine (L-NIL)] did not affect the decreased proteoglycan production, which suggests a post-translational regulation. In contrast, N-omega nitro-L-arginine (L-NNA) a more specific inhibitor of NOS I and III abrogated the cyclic tensile stretch-dependant inhibition of proteoglycan production. These results suggest that cyclic tensile stretch regulates proteoglycan production through a post-translational mechanism involving nitrite oxide. This result could be of interest in the development of local therapeutic strategies aimed at controlling intervertebral disc degeneration. Show more

Keywords: Intervertebral disc, mechanical stretch, annulus fibrosus, proteoglycan, chondrocyte, nitrite oxide

Citation: Biorheology, vol. 43, no. 3-4, pp. 303-310, 2006

Authors: Hajjar, Denise | Santos, Marinilce F. | Kimura, Edna Teruko

Article Type: Research Article

Abstract: Functional orthopedic appliances correct dental malocclusion partially by exerting indirect mechanical stimulus on the condylar cartilage, modulating growth and the adaptation of orofacial structures. However, the exact nature of the biological responses to this therapy is not well understood. Insulin-like growth factors I and II (IGF-I and II) are important local factors during growth and differentiation in the condylar cartilage [D. Hajjar, M.F. Santos and E.T. Kimura, Propulsive appliance stimulates the synthesis of insulin-like growth factors I and II in the mandibular condylar cartilage of young rats, Arch. Oral Biol. 48 (2003), 635–642]. The bioefficacy of IGFs at the cellular …level is modulated by IGF binding proteins (IGFBP). The aim of this study was to verify the mRNA and protein expression of IGFBP-3, IGFBP-4, IGFBP-5 and IGFBP-6 in the condylar cartilage of young male Wistar rats that used a mandibular propulsive appliance for 3, 9, 15, 20, 30 or 35 days. For this purpose, sagittal sections of decalcified and paraffin-embedded condyles were submitted to immunohistochemistry and the condylar cartilage to RT–PCR. The control group showed a gradual increase in the protein expression of all IGFBPs, except IGFBP-4. Following use of the appliance, IGFBP-3 and IGFBP-6 expression decreased in the early stage of the treatment. At 20 days of treatment there was a decline in the IGFs and IGFBP-3, IGFBP-4 and IGFBP-5 expression and at 30 days there was a peak in the IGFs and all IGFBPs expression except for IGFBP-3 where the peak was observed in the control animals. The expression patterns of all IGFBPs in the condylar cartilage were similar. The modulation of IGFBP-3, -4, -5 and -6 expression in the condylar cartilage in response to the propulsive appliance suggests that those peptides are involved in the mandibular adaptation during this therapy. Show more

Keywords: Insulin-like growth factor binding protein, mechanical stress, mandibular condyle, cartilage, functional orthopedics

Citation: Biorheology, vol. 43, no. 3-4, pp. 311-321, 2006

Authors: Yao, Hai | Gu, Wei Yong

Article Type: Research Article

Abstract: A 3D finite element model for charged hydrated soft tissues containing charged/uncharged solutes was developed based on the multi-phasic mechano-electrochemical mixture theory (Lai et al., J. Biomech. Eng. 113 (1991), 245–258; Gu et al., J. Biomech. Eng. 120 (1998), 169–180). This model was applied to analyze the mechanical, chemical and electrical signals within the human intervertebral disc during an unconfined compressive stress relaxation test. The effects of tissue composition [e.g., water content and fixed charge density (FCD)] on the physical signals and the transport rate of fluid, ions and nutrients were investigated. The numerical simulation showed that, during disc compression, …the fluid pressurization was more pronounced at the center (nucleus) region of the disc while the effective (von Mises) stress was higher at the outer (annulus) region. Parametric analyses revealed that the decrease in initial tissue water content (0.7–0.8) increased the peak stress and relaxation time due to the reduction of permeability, causing greater fluid pressurization effect. The electrical signals within the disc were more sensitive to FCD than tissue porosity, and mechanical loading affected the large solute (e.g., growth factor) transport significantly, but not for small solute (e.g., glucose). Moreover, this study confirmed that the interstitial fluid pressurization plays an important role in the load support mechanism of IVD by sharing more than 40% of the total load during disc compression. This study is important for understanding disc biomechanics, disc nutrition and disc mechanobiology. Show more

Keywords: Intervertebral disc, triphasic theory, finite element method, solute transport, soft tissue mechanics

Citation: Biorheology, vol. 43, no. 3-4, pp. 323-335, 2006

Authors: Chen, M.-Y. | Jeng, L. | Sun, Y.-L. | Zhao, C.-F. | Zobitz, M.E. | Moran, S.L. | Amadio, P.C. | An, K.-N.

Article Type: Research Article

Abstract: Knowledge of the adaptation of the soft tissue to mechanical factors and biomolecules would be essential to better understand the mechanism of tendon injury and to improve the outcome of tendon repair. The responses to these factors could be different for the distinct types of cells in the tendon: cells from the tendon sheath, fibroblasts from the epitenon surface, or fibroblasts from the internal endotenon. In this study, we examined the mechanical and histological characteristics of the rate of contraction of the collagen gel seeded with epitenon and endotenon fibroblasts. The rate of contraction and the mechanical property of the …contracted construct depend on the gel concentration and also the treatment of TGF-β1 . Show more

Keywords: Gel concentration, TGF-β, fibroblast, tendon, cell culture, biomechanics

Citation: Biorheology, vol. 43, no. 3-4, pp. 337-345, 2006

Authors: Kato, Yukio | Nakamura, Shigeo | Nishimura, Masahiro

Article Type: Research Article

Abstract: Hyaluronan (HA) has viscoelastic, anti-inflammatory and protective actions in joint tissues, and is being widely used for treatment of OA and RA patients. However, the mechanisms underlying the pharmacological action of HA on OA and RA have not been fully understood. In this article, we review the molecular weight-dependent, anti-inflammatory actions of HA preparations – produced in Japan – in joint tissues, and show that the molecular weight of HA, but not its concentration, is crucial for maintenance of cartilage elasticity.

Keywords: Hyaluronan, aggrecan, cartilage, OA, RA, elasticity

Citation: Biorheology, vol. 43, no. 3-4, pp. 347-354, 2006

Authors: Archer, Charles W. | Buxton, Paul | Hall, Brian K. | Francis-West, Philippa

Article Type: Research Article

Abstract: This article has been retracted. The original article can be found on: http://dev.biologists.org/cgi/reprint/130/19/4729.

Citation: Biorheology, vol. 43, no. 3-4, pp. 355-370, 2006

Authors: Huselstein, C. | de Isla, N. | Kolopp-Sarda, M.N. | Kerdjoudj, H. | Muller, S. | Stoltz, J.F.

Article Type: Research Article

Abstract: The cartilage is a hydrated connective tissue in joints that withstands and distributes mechanical forces. The chondrocytes utilize mechanical signals to regulate their metabolic activity through complex biological and biophysical interactions with the extracellular matrix (ECM). The aim of this work was to study the influence of mechanical stress on cells behavior cultured in 3D biosystems (alginate and alginate supplemented with hyaluronate). After mechanical stimulation, cell viability and cell death process were the main studied parameters. Our results indicated that viability and cell cycle progression were inhibited under mechanical stimulation, as far as the extracellular matrix was not yet synthesized. …In contrast, on day 21, the mechanical stimulation had positive effect on these parameters. Show more

Keywords: Chondrocyte, alginate hydrogel, cell viability, mechanical stimulation, extracellular matrix

Citation: Biorheology, vol. 43, no. 3-4, pp. 371-375, 2006