OBJECTIVEThe present study aimed to evaluate the analgesic and anti-inflammatory effects of far infrared-emitting ceramics (cFIRs) in a model of persistent inflammatory hyperalgesia and to elucidate the possible mechanisms of these effects.

METHODSMice were injected with complete Freund's adjuvant (CFA) and treated with cFIRs via placement on a pad impregnated with cFIRs on the bottom of the housing unit for different periods of time. Mice underwent mechanical hyperalgesia and edema assessments, and tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-10 levels were measured. Twenty-four hours after CFA injection and 30 min before cFIR treatment, mice were pretreated with a nonselective adenosinergic antagonist, caffeine, the selective adenosine receptor A antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX), the selective cannabinoid receptor type 1 antagonist, AM281, the selective cannabinoid receptor type 2 antagonist, AM630, or the nonselective opioid receptor antagonist, naloxone, and mechanical hyperalgesia was assessed.

RESULTScFIRs statistically (P < 0.05) decreased CFA-induced mechanical hyperalgesia ((82.86 ± 5.21)% in control group vs (56.67 ± 9.54)% in cFIR group) and edema ((1699.0 ± 77.8) μm in control group vs (988.7 ± 107.6) μm in cFIR group). cFIRs statistically (P < 0.05) reduced TNF-α ((0.478 ± 0.072) pg/mg of protein in control group vs (0.273 ± 0.055) pg/mg of protein in cFIR group) and IL-1β ((95.81 ± 3.95) pg/mg of protein in control group vs (80.61 ± 4.71) pg/mg of protein in cFIR group) levels and statistically (P < 0.05) increased IL-10 ((18.32 ± 0.78) pg/mg of protein in control group vs (25.89 ± 1.23) pg/mg of protein in cFIR group) levels in post-CFA-injected paws. Peripheral pre-administration of inhibitory neuroreceptor antagonists (caffeine, DPCPX, AM281, AM630 and naloxone) prevented the analgesic effects of cFIRs (P < 0.05).

CONCLUSIONThese data provide additional support for the use of cFIRs in the treatment of painful inflammatory conditions and contribute to our understanding of the neurobiological mechanisms of the therapeutic effects of cFIRs.

BACKGROUND: Venous ulcer represents the most advanced stage of chronic venous insufficiency. It is an important public health problem and has a significant impact on patients' quality of life due to chronic pain, inability to work, need for hospitalization and frequent outpatient follow-up. OBJECTIVE: We investigated the treatment benefits of far-infrared ceramic (cFIR), in a 90-day study of lower limb venous ulcers and looked at ulcer healing scores, quality of life, serum bio-markers of oxidative stress and antioxidant defense enzymes. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS: This is a randomized double-blind placebo-controlled study conducted in the Vascular Surgery Service of a hospital located in the northwest region of the State of Rio Grande do Sul, Brazil. We included patients with lower limb venous ulcers who were randomized to use either a bioceramics wrap or a placebo wrap for 90 days. MAIN OUTCOME MEASURES: The following evaluations were conducted at baseline and after 15, 30, 60 and 90 days: ulcer healing score, quality of life, and serum markers of oxidative stress and antioxidant enzyme activity. RESULTS: Patients (n = 24) with lower limb venous ulcers were randomized into two treatment groups. cFIR decreased the ulcer size on day 30 (P = 0.042) and 90 (P = 0.034) and the total ulcer healing scale scores on day 30 (P = 0.049) and 90 (P = 0.02) of the treatment, when compared to baseline. Additionally, cFIR improved tissue type (epithelial tissue) on day 60 (P = 0.022) when compared to baseline evaluation. CONCLUSION: cFIR clinically improved ulcer healing in patients with lower limb venous ulcers. TRIAL REGISTRATION RBR-8c7xzn on ReBEC.