title: Light and low-frequency pulsatile hydrostatic pressure enhances extracellular matrix formation by bone marrow mesenchymal cells: an in-vitro study with special reference to cartilage repair.
abstract: Ovine bone marrow mesenchymal cells (BMMCs) were seeded on to non-woven filamentous plasma-treated polyester scaffolds and cultured in a chondrogenic medium for 4 weeks. Thereafter a pulsatile hydrostatic pressure (PHP) was applied to these cell-scaffolds constructs at an amplitude of 0.1 MPa and frequency of 0.25 Hz, for 30 min a day, over a period of 10 days. Samples (n = 6) were removed 24 h after PHP stimulation at days 1, 4, 7, and 10 for biochemical analysis. Similar analyses were conducted, at the same time points, on control samples that were not subjected to a PHP. The results showed that the glycosaminoglycan (GAG) content did not significantly increase until after the application of a PHP for 7 days. The GAG content was 1.5 and 2.7 times higher in the PHP group than in the control group at days 7 and 10 respectively (p<0.01). The deoxyribonucleic acid (DNA) content was 1.5 times greater in the PHP group than in the control group at day 10 (p<0.01). GAG synthesis amounts, expressed as the total GAG contents per microgram of DNA, were 1.6 and 1.8 times higher in the PHP group than in the control group at days 7 and 10 respectively (p<0.01). The total collagen content in the medium did not change until after PHP application for 10 days, when it was 1.9 times higher than the control (p < 0.05). The results suggest that a light PHP applied at a low frequency has a cumulative stimulatory effect on the BMMCs' metabolic activities including cell proliferation and synthesis of the extracellular matrix.
authors.affiliation: Bioengineering Division, Academic Unit of Musculoskeletal Disease, University of Leeds, Leeds, UK. z.j.luo@leeds.ac.uk
authors.forename: Z-J
authors.initials: ZJ
authors.lastname: Luo
authors.forename: B B
authors.initials: BB
authors.lastname: Seedhom
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology / Q000528:radiation effects; D002454:Cell Differentiation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000502:physiology* / Q000528:radiation effects; D020219:Chondrogenesis / Q000502:physiology / Q000528:radiation effects; D005109:Extracellular Matrix / Q000502:physiology* / Q000528:radiation effects; D050724:Fractures, Cartilage / Q000503:physiopathology / Q000601:surgery; D008027:Light; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology* / Q000528:radiation effects; D011312:Pressure; D012756:Sheep