Resumo

Objectives: To evaluate vascular flow dynamics, clinical ischemia, and histopathological outcomes following intra-arterial injection of polynucleotide (PN) formulations with differing viscosities, compared with normal saline (NSS) and cross-linked hyaluronic acid (HA), using a rabbit central ear artery (CEA) model. Introduction: PN injectables are increasingly used in aesthetic medicine; however, their vascular safety profile following inadvertent intra-arterial injection remains poorly defined. Unlike cross-linked HA, PN lacks a specific reversal agent, making clarification of its intravascular behavior essential. Materials / method: This randomized controlled animal study included 25 rabbits allocated to 5 groups (5 rabbits or 10 ears per group), each receiving a 0.2 mL intra-arterial injection of NSS, Rejuran HB Plus (low-viscosity PN combined with non–cross-linked HA), Rejuran S (high-viscosity PN), Conjuran (higher-viscosity PN), or cross-linked HA into the CEA. Arterial flow dynamics (including retrograde flow and flow obstruction), the presence of visible emboli at 24 hours, clinical changes in the ear at day 7, and histopathological changes at day 7 were assessed. Results: Retrograde flow occurred with Rejuran HB Plus (80%), Conjuran (100%), and cross-linked HA (100%), but not with NSS or Rejuran S. Flow obstruction >5 minutes increased with viscosity: Rejuran S (20%), Rejuran HB Plus (40%), Conjuran (70%), and cross-linked HA (100%). No PN groups showed transparent emboli at 24 hours or clinical ischemia at day 7, whereas all cross-linked HA ears developed both. Histology of PN groups showed no vasculitis, vasculopathy, or inflammation, while cross-linked HA caused intravascular foreign material, inflammation, and cartilage necrosis. Conclusion: In this animal model, intra-arterial injection of PN formulations resulted in transient alterations in arterial flow dynamics without evidence of persistent embolization, tissue ischemia, or adverse histopathological changes, in contrast to cross-linked HA. These findings suggest a more favorable vascular safety profile for PN; however, clinicians should comply with key injection safety principles to avoid inadvertent intra-arterial injection.