Bone healing in critically sized defects in rat calvaria, transplanted with chitosan alone, or associated with collagen and / or chondroitin sulfate:histological and histomorphometric pilot study

Background: Chitosan is a natural biopolymer that has gained a special interest in bone regeneration in recent years. Objective: The objective of this study is to show the bone formation obtained following a transplantation of sponges of chitosan alone, chitosan combined with chondroitin sulfate or chitosan combined with chondroitin sulfate and collagen, in rat critical calvarial bone defects. Material and Methods: 12 Wistar rats were divided into 4 groups of 3 rats each. Critically sized bone defects were made in calvaria, and grafted by sponges of:collagen / chitosan / chondroitin (group 1), chitosan (group 2), chitosan / chondroitin sulfate (group3). Bone defects of group 4 remained empty for control. The animals were sacrificed 12 weeks after the surgery. Results: Histological analysis showed the formation of lamellar bone in the chitosan group. In the chitosan / chondroitin sulfate group, formation of a less mature bone than that of the chitosan group was also observed. However, the least bone formation was observed in the collagen / chitosan / chondroitin sulfate group. Histological sections showed the presence of fibrous tissue. The results for this group are similar to the control group. In groups 2 and 3, the materials appear completely resorbed while in group 1 the resorption of the matrix was incomplete. Conclusion: Despite the size of the sample, this study has shown that chitosan alone or in combination with chondroitin sulfate promotes bone formation. On the other hand, the combination chitosan / chondroitin sulfate / collagen showed a negative result.