The Biomechanical and Histological Effects of Diabetes on Tendon Healing: Experimental Study in Rats

Abstract

The aim of this study was to investigate the biomechanical and histological perspectives of healing of Achilles tendon in diabetic rats and compare the results with non-diabetic subjects. Fifty four adult Wistar Albino rats weighing 300-350 g were used throughout the study. Six animals were excluded from the study and replaced. Rats were randomly assigned to either the experimental or the control group comprised of 24 rats in each. Diabetes was induced in experimental group with streptozotocin. 3 days after the induction of diabetes, both Achilles tendons were transected 5 mm proximal to their insertions to the calcaneal bone and repaired by using 6/0 polypropylene sutures with modified Kessler method. At weeks 2, 4 and 6, eight rats from each group were euthanized. Left Achilles tendons including the repair site were prepared for histological evaluation and right legs were prepared for mechanical testing. When compared to control group, diabetic animals displayed a lower peak force for failure in each of the second, fourth and sixth week. The differences between the groups in each week were found to be significant in statistical assessments (p<0.05). Histologic assessment revealed that the diabetic animals had significantly less amount of fibroblast proliferation and lymphocyte infiltration compared to the control group. There is significant delay in tendon strength at the end of week 2, 4 and 6 postoperatively in the diabetic rats. Therefore diabetic individuals require specific postoperative follow up and rehabilitation procedures.

Tendinopathy in diabetes mellitus patients—Epidemiology, pathogenesis, and management

“…The number of inflammatory cells, blood vessels, and proliferating cells were lower; the deposition and structural organization of collagen fibers and proteoglycans were impaired and the expression of MMPs was dysregulated in diabetic animals compared with the nondiabetic animals after tendon injury (Appendix S3). Osteochondroid metaplasia was noticed in the diabetic group but not in the nondiabetic group as early as day 15 57 and week 6 58 after Achilles tendon transection and repair in rat models. The delayed healing responses have implications on the early and more frequent development of tendinopathy after microtrauma and the poor prognosis of tendinopathy in diabetic patients.…”

Patients With Diabetes Mellitus Have a Higher Risk of Tendon Retear After Arthroscopic Rotator Cuff Repair: A Meta-analysis

“… 1 Previous studies have shown the regenerative capability of tendons to be compromised in patients with diabetes because of less fibroblast proliferation and lymphocyte infiltration in healing tendons associated with tendon weakness. 1 , 3 , 6 An animal study indicated that DM impairs tendon-bone healing after rotator cuff repair. 2 Several clinical studies have further investigated the relationship between DM and retearing of the rotator cuff tendon.…”

Influence of diabetes on tissue healing in orthopaedic injuries

“…Disorders of healing are observed at the structural, biochemical and molecular level. Healing tendons in diabetic individuals exhibit worse biomechanical properties: reduced stiffness, reduced tensile stress, reduced maximum load, decreased Young's modulus . Young's modulus is also known as the elastic modulus and is defined as the quotient of stress (MPa) and strain (proportional deformation) in a material.…”

“…In the inflammatory phase of healing, significant reduction of neutrophil and macrophage infiltration at the lesion site was observed . In turn, the proliferative phase is characterized by decreased amounts of fibroblast and lymphocyte infiltration, therefore, cell proliferation is limited. There is also a decrease in vascularization in the early proliferative phase (evaluated on the 7th day after injury, unchanged on the 28th day) .…”

“…In turn, the proliferative phase is characterized by decreased amounts of fibroblast and lymphocyte infiltration, therefore, cell proliferation is limited. There is also a decrease in vascularization in the early proliferative phase (evaluated on the 7th day after injury, unchanged on the 28th day) . Another deviation in the healing process is the decrease of collagen type I, collagen type III and biglycan synthesis within 2 weeks of injury .…”