Flexor tendon repair in vitro: A comparative histologic study of the rabbit, chicken, dog, and monkey

Abstract

Flexor tendon healing in four different animal species was explored in a tissue culture system. Ninety percent transverse lacerations were made in 88 tendon segments obtained from rabbits, chickens, dogs, and monkeys. The tendons were removed from culture and studied by light and electron microscopy at intervals of 3, 6, 9, and 12 weeks. A characteristic sequence of repair including epitenon thickening, cellular differentiation, cell migration, and phagocytosis was seen in each of the repaired tendons. The endotenon cells of several animal tendons appeared to be synthesizing collagen. There was a consistent difference in the rate of healing between the four species. The rabbit tendons demonstrated nearly complete closure of the repair site by 12 weeks. A lesser response was seen in the chicken, followed by the dog and monkey. The differences in healing rate appeared to be due to the non-species-specific in vitro culture media. The in vitro flexor tendon culture system is particularly useful in studying the tendon repair responses of various species with the contributions of vascularity and synovial cells excluded.

What We Should Know Before Using Tissue Engineering Techniques to Repair Injured Tendons: A Developmental Biology Perspective

“…These cells migrate to the lesions and synthesize new matrix. 80,81 However, the molecular mechanism controlling these events, and whether fully differentiated replacement tendon forms at these sites, remains unclear. The use of molecular markers of tenocyte differentiation will help resolve this issue.…”

Twenty‐five years of tendon and ligament research

“…71 However, the scope of research greatly expanded as the process and stages of healing were described. Early work with flexor tendons in several animal models 72,73 and cell culture 74 helped identify the three phases of tendon healing: inflammation, fibroplasia, and remodeling. At the same time, the extent and role of intrinsic and extrinsic healing were investigated.…”

Tendon injury and repair – A perspective on the basic mechanisms of tendon disease and future clinical therapy

“…1). The extent of intrinsic and extrinsic compartment coordination in functional repair, and discord in degenerative processes, is still poorly understood [20][21][22][23][24].…”