Optimal number of chemical extraction treatments for maintaining the biological properties of an allogeneic tendon

Abstract

The aim of this study was to explore the biological effects of the amount of chemical extraction treatments performed on an allogeneic tendon through histomorphology, biological mechanics testing, and an immunogenicity assay. Sixteen New Zealand rabbits (body weight 2.5-3.0 kg) were randomly divided into four groups: group A (chemical extraction once), group B (chemical extraction twice), group C (chemical extraction three times), and group D (blank control group), with four rabbits in each group. The Achilles tendons of each rabbit were separated and subjected to a chemical extraction process with Triton X-100 and sodium deoxycholate, followed by hematoxylin and eosin staining, electron microscopy observation, biomechanical testing, and mixed lymphocyte culture. There were no significant differences in the surface color and fiber bundles between groups A and B and the blank control group, whereas group C showed clear differences from the blank control group with a rough surface, loose fibers, and poor tension. There were no significant differences in the biomechanics among the four groups. The four groups showed significant differences in the lymphocyte conversion ratio, with reduced rates of lymphocyte conversion along with increasing treatment numbers. Two chemical extractions of the tendon allowed for retaining most of the integrity of the original tendon fiber while removing immunogenicity with good biological properties. These findings lay a foundation for application of this method to human tendons so as to provide a good tissue source for tendon transplantation.

Optical Microscopy and Electron Microscopy for the Morphological Evaluation of Tendons: A Mini Review

“…evaluated the arrangement of the tendon collagen in human peroneus longus muscle in SEM, and found that the collagen fibers were disoriented and appeared straight without helical coils in an older adult cadaver. Provenzano and Vanderby evaluated structural change between fetal and skeletally mature rats, while Chen et al . evaluated the influence of chemical extraction on allogenic tendons, with similar results being obtained via SEM and HE staining, showing collagen fibers that had a more disordered arrangement with fewer residual cells after repeated chemical extraction treatments.…”

“…Optical microscopy is mostly used to visualize collagen fibers and cells. To evaluate the influence of chemical extraction on allogenic tendons, Chen et al . stained tendon specimens with HE and observed the collagen fibers with disordered arrangement and fewer residual cells after repeated chemical extraction treatments (Fig.…”

“…In addition to the preparation methods, the contents and indexes of the morphological evaluation vary greatly by the purposes of the morphological studies of tendons, and different contents are observed and evaluated according to the study design. Some studies evaluate the morphology of tendons in vitro , mainly focusing on the structural changes to collagen fibers or collagen fibrils with the higher magnification of an electron microscope. Similarly, in some studies on allogenic tendon treatments, resident cells are investigated.…”