[Protective effect of graphene heating film far-infrared hyperthermia against frostbite in mice].

Objectives: To investigate the protective effects of graphene heating film far-infrared (FIR) hyperthermia therapy against frostbite in mice and its impacts on microcirculation and coagulation function.

Methods: Seventy-six C57BL/6J mice were randomized into control, model, graphene-FIR, and carbon fiber-FIR groups. After 7-day FIR intervention (4 h/day), the mice were subjected to acute (4 ℃, 4 h) and intermittent (4 ℃, 4 h/day for 3 days) cold exposure and the changes in rectal temperature were monitored. In liquid nitrogen frostbite experiment, 24 ICR mice were divided into model, graphene-FIR, and carbon fiber-FIR groups, and after a 7-day FIR pretreatment (4 h/day), the liquid nitrogen frostbite models were established and apparent scores of the wounds were assessed on days 3 and 6 after modeling. In carrageenan-induced thrombosis experiment, 40 ICR mice were allocated to control, model, graphene-FIR, carbon fiber-FIR, and prazosin groups to test the effect of a 7-day FIR intervention on thrombosis induced by intraperitoneal carrageenan injection (2.5 mg/kg) by measuring thrombus length, blood perfusion, and serum biomarkers (6-keto-PGF1α, TXB2, t-PA, IL-6, IL-1β, TNF‑α) 24 h after the injection.

Results: The mice in graphene-FIR group showed significantly elevated rectal temperature in cold exposure tests. In mice with liquid nitrogen-induced frostbite, graphene-FIR treatment significantly reduced the wound scores and reduced frostbite area, producing better effects than carbon fiber. In mice with carrageenan-induced thrombosis, graphene-FIR treatment significantly decreased tail thrombosis length and thrombosis area, increased blood perfusion, lowered serum levels of TXB2, TNF-α and IL-6, and increased the levels of 6-keto-PGF1α and t-PA.

Conclusions: Graphene heating film FIR therapy can alleviate frostbite injury in mice by improving microcirculation, suppressing thrombosis and inflammatory responses, and reducing coagulation dysfunction.