VARIATIONS IN CELLULAR PROLIFERATION AND MATRIX SYNTHESIS IN INTRASYNOVIAL AND EXTRASYNOVIAL TENDONS - AN IN-VITRO STUDY IN DOGS

Intrasynovial and extrasynovial flexor tendon grafts recently have bee n shown to have dissimilar patterns of cellular survival and host inte gration within the digital sheath. in an effort to determine if fundam ental differences exist between these two types of tendons, we investi gated the biochemical composition and cellular activity of intrasynovi al and extrasynovial tendon segments of 12 adult mongrel dogs in short -term explant culture in MCDB 105 and in DMEM media. Proteoglycan, col lagen and noncollagen protein synthesis and content and DNA synthesis were determined following culture in both media. Intrasynovial tendon segments cultured in MCDB 105 medium synthesized significantly less co llagen, noncollagen protein, and DNA and had similar amounts of proteo glycans compared to extrasynovial tendons. Comparison of intrasynovial and extrasynovial tendon segment responses in DMEM medium showed that intrasynovial tendons synthesized more proteoglycan, protein, and DNA than they did in MCDB 105. Extrasynovial tendons had similar rates of matrix component and DNA synthesis in both media. Findings that the s ynthesis of matrix components and DNA between intrasynovial flexor and extrasynovial peroneal tendon segments differ significantly indicate that intrasynovial flexor tendons may be specially adapted to the nutr itional milieu provided by an intrasynovial environment. These data ar e supported by the selective successful stimulation of fibrocartilagin ous segments within intrasynovial Flexor tendons in media favored for the culture of cartilaginous tissue.