Platelet lysate-silk fibroin injectable hydrogel as a potential biofunctional and biomechanical platform for canine intervertebral disc repair.

Intervertebral disc degeneration (IVDD) in dogs remains a major clinical problem that requires regenerative strategies capable of restoring both biological activity and mechanical stability. This study developed and evaluated an injectable platelet lysate-silk fibroin (PL-TSF) hydrogel designed as a dual-functional platform for disc repair. Biofunctional and biomechanical performances were examined using canine chondrocyte culture and nucleotomized spinal segments. The PL-TSF hydrogel provided a controlled trophic microenvironment that enhanced chondrocyte proliferation and induced early upregulation of anabolic markers (SOX9, ACAN, COL2A1), while concurrently suppressing catabolic (MMP13) and inflammatory (IL1B) responses compared with controls. In contrast, direct platelet lysate exposure triggered an acute anabolic burst that was accompanied by elevated catabolic signaling. Biomechanically, the hydrogel enhanced viscoelastic damping and partially restored axial stiffness, indicating improved load-distribution capability after discectomy. These results demonstrate the dual biofunctional and biomechanical advantages of the PL-TSF hydrogel, providing controlled trophic stimulation and transient mechanical reinforcement that address both cellular regeneration and structural stabilization in intervertebral disc repair. This highlights its potential as a minimally invasive regenerative therapy for canine IVDD.