Evaluation of neovascularization in murine osteoarthritis using micro-computed tomography

The study aimed to examine neovascularization in murine osteoarthritis (OA) using micro-computed tomography (μCT).

OA was induced in eighteen mice through intra-articular collagenase injection, designating the left hindlimbs as OA models and the right hindlimbs as controls. Mice were monitored for 4, 8, or 12 weeks post-induction. Hindlimbs underwent overnight tissue fixation and were then subjected to μCT scanning. Quantification of unnamed arterial branches spanned from the femoral artery's terminal branching point to 2.5 mm below the tibial plateau.

Baseline characteristics did not differ significantly between control and OA-induced groups (p > 0.05). Collagenase-treated limbs showed a significantly higher number of unnamed arterial branches compared to controls (11.6 vs. 7.5, p < 0.001), reflecting increased neovascularization. This elevation persisted across all post-induction time points, with no significant time-dependent trend (p = 0.09) or interaction between time and treatment group (p = 0.17). Spatial analysis revealed that neovessels were predominantly localized to peri-meniscal (61 %) and subchondral (29 %) regions.

Collagenase-induced OA in mice results in sustained and spatially patterned neovascularization, detectable using non-contrast μCT. These findings underscore the utility of μCT for tracking vascular remodeling in OA and highlight potential anatomical targets for angiogenesis-modulating therapies.