Affiliations: Institut National de la Santé Et de la Recherche Médicale (INSERM) UMR-S-747, Université Paris 5, UFR Biomédicale, 45 Rue des Saints-Pères, 75006 Paris, France | Service de rééducation et de réadaptation de l'appareil locomoteur et des pathologies du rachis, Réseau Fédératif de Recherche sur le Handicap INSERM, Hôpital Cochin, Assistance Publique-Hôpitaux de Paris, Université Paris 5, 27 rue du faubourg Saint-Jacques, 75679 Paris, France
Note: [] Address for correspondence: Francois Rannou, MD, PhD, Service de rééducation et de réadaptation de l'appareil locomoteur et des pathologies du rachis, Hôpital Cochin, Assistance Publique-Hôpitaux de Paris, Université Paris 5, 27 rue du faubourg Saint Jacques, 75679 Paris, France. Tel.: +33 1 58 41 25 35; Fax: +33 1 58 41 25 45; E-mail: [email protected].
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.
