Abstract
Background:
The growth plate is important in new bone developing; therefore, its injury may cause closing the plate in premature period and effect on growth of the bone. This injury can lead to deformity of the skeleton, if not treated correctly and not monitored for a long time.

Aim:
This study was aimed to evaluate radiographically the role of autogenous cartilage grafts impregnated with Magnesium Oxide Nanoparticles (MgONPs) in growth plate regeneration and in preventing the bone bridge formation at the growth plate defect.

Methods:
Ten adult rabbits were divided into two groups: a control group and an MgO group. A 2 mm section of the proximal tibia's growth plate was surgically removed from all rabbits. In the control group, the gap was filled with an autogenous ear cartilage graft soaked in normal saline. While in the MgO group, the gap was filled with an autogenous graft soaked in a 50 μg/ml MgONPs solution.

Results:
Post-surgery, both groups showed immediate lameness. However, lameness resolved in the MgO group after 3 days in compared to the control. The radiographic results in 7, 14, 21, and 28 days after surgery showed early growth plate closure in the control group, without limb shortening or angular deformity. In contrast, the MgO group exhibited a small periosteal reaction around the growth plate gap, with no evidence of bone bridge formation.

Conclusion:
Local application of MgONPs to a growth plate defect may postpone bone bridge formation, potentially preventing bone growth disorders. This finding highlights a promising strategy for managing growth plate injuries.

Key words: Growth plate; Magnesium oxide nanoparticles; Rabbit; Radiography.