Hydroxyapatite-chitosan composites derived from sea cucumbers and shrimp shells ameliorate femoral bone defects in an albino rat model

Background and Aim: A bone defect is defined as a critically sized autologous bone and a bone gap. Bone grafting is
one of the most commonly used surgical methods to enhance bone regeneration in orthopedic procedures. A composite of
collagen, hydroxyapatite (HA), and chitosan (Ch) is suitable as a bone matrix and stimulates ossification. This study aimed to evaluate the use of natural HA-Ch composites derived from sea cucumbers and shrimp shells and quantify the levels of cytokines, polymorphonuclear neutrophils (PMNs), serum liver enzymes, calcium, phosphate, and procollagen type 1 N-terminal propeptide (PINP) in albino rats with femoral bone defects.
Materials and Methods: A total of 48 albino rats with femoral bone defects were divided into 4 groups (n = 12 each): (C−) placebo, (C+) polyethylene glycol, (T1) HA, and (T2) HA–Ch groups. Each group was divided into two subgroups
(n = 6 each), with euthanization on 7- and 42-day post-treatment, respectively. Procollagen Type 1 N-terminal propeptide and the cytokines interleukin (IL)-4, IL-6, IL-10, and tumor necrosis factor-alpha were quantified using enzyme-linked immunosorbent assay. Flow cytometry was performed to evaluate PMNs. A clinical chemistry analyzer was used to measure the serum levels of liver enzymes, calcium, and phosphate.
Results: There was a significant decrease in the level of IL-6 on 7 days and in the level of IL-10 on 42 days in the HA-Ch group. The level of PMNs also decreased significantly on 7 and 42 days in the HA-Ch group. Regarding serum liver
enzymes, alkaline phosphatase (ALP) levels in the HA-Ch group increased significantly on 42 days. Calcium and phosphate levels increased significantly on 7 and 42 days in the HA and HA-Ch groups, and PINP levels increased significantly on 7 and 42 days in the HA-Ch group.
Conclusion: The HA-Ch composite derived from sea cucumbers and shrimp shells ameliorated femoral bone defects in
albino rats. The HA-Ch composite modulated the levels of IL-6, IL-10, PMNs, ALP, calcium, phosphate, and PINP on
7- and 42-day post-treatment.