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Vet Comp Orthop Traumatol 1999; 12(04): 166-172
DOI: 10.1055/s-0038-1632485
Original Research
Schattauer GmbH

Proteoglycan Composition and Biosynthesis in Superficial and Deep Digital Flexor Tendons of Standardbred Horses

L. Micklethwaite
1   From the Institute of Bone and Joint Research and Department of Surgery, University of Sydney at the Royal North Shore Hospital St. Leonards, NSW and Equine Performance Laboratory, University of Sydney, Rural Veterinary Centre, Camden, NSW, Australia
,
P. Ghosh
1   From the Institute of Bone and Joint Research and Department of Surgery, University of Sydney at the Royal North Shore Hospital St. Leonards, NSW and Equine Performance Laboratory, University of Sydney, Rural Veterinary Centre, Camden, NSW, Australia
,
C. B. Little
1   From the Institute of Bone and Joint Research and Department of Surgery, University of Sydney at the Royal North Shore Hospital St. Leonards, NSW and Equine Performance Laboratory, University of Sydney, Rural Veterinary Centre, Camden, NSW, Australia
,
D. R. Hodgson
1   From the Institute of Bone and Joint Research and Department of Surgery, University of Sydney at the Royal North Shore Hospital St. Leonards, NSW and Equine Performance Laboratory, University of Sydney, Rural Veterinary Centre, Camden, NSW, Australia
,
R. J. Rose
1   From the Institute of Bone and Joint Research and Department of Surgery, University of Sydney at the Royal North Shore Hospital St. Leonards, NSW and Equine Performance Laboratory, University of Sydney, Rural Veterinary Centre, Camden, NSW, Australia
› Author Affiliations
Further Information

Publication History

Received 18 March 1999

Accepted 17 April 1999

Publication Date:
08 February 2018 (online)

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Summary

Proteoglycan (PG) levels and their respective biosynthesis were determined in explant cultures taken from the mid-metacarpal (MMC) and metacarpophalangeal (MCP) regions of normal equine superficial and deep digital flexor tendons. Five standard-bred horses (2-5 years old) were used and explants dissected from the MMC and MCP regions of the superficial and deep digital flexor tendons. The explants (3 mm2) were cultured in Ham’s F12 media supplemented with 1% FBS. After 24 h, Na2S35SO4 was added and the culture continued for a further 48 h. The media was removed and the explants were lyophilized and weighed. The explants and media were then subject to papain digestion and the DNA and sulphated glycosaminoglycans (S-GAG) concentrations and incorporation of [35S] sulphate into PGs determined by established methods.

The MMC regions of the superficial and deep digital flexor tendons contained less PGs than the MCP regions and these were predominantly small. The MCP regions, not only contained higher concentrations of PGs, but these were of larger hydrodynamic size. The incorporation of [35S] sulphate into PGs was also higher in explants from the MCP region. These data indicate that in those regions of equine flexor tendon, subjected to both, compression and tension, PG content and biosynthesis is higher than in regions which only transmit tensional loads. These findings are consistent with the adaptive role of tenocytes to the nature and level of the mechanical stresses imposed upon them.

The proteoglycans (PGs) and DNA content and their biosynthesis were determined in cultures of expiants obtained from the mid-metacarpal (MMC) and metacarpophalangeal (MCP) regions of normal superficial and deep digital flexor tendons of five standard bred horses (2– years old). It was shown that the MMC region of the superficial and deep flexor tendon contained less PGs than the MCP regions. Moreover, the biosynthesis of PGs was enhanced in the MCP explants and the size of these molecules was larger than made by cells of the MMC region.

Keywords

Equine - proteoglycans - biosynthesis