Avocado/soybean unsaponifiables administered at 300 mg/kg/day intraperitoneally significantly reduced mechanical allodynia percentage decrease from 51.45% to 30.20% (p=0.001), temperature asymmetry from 1.95°C to 0.75°C (p<0.001), and paw edema from 14.75% to 8.35% (p=0.004) in a rat CRPS-I model after 28 days.
Does early systemic administration of avocado/soybean unsaponifiables prevent the development of CRPS-I-like features in a rat model of tibial fracture and cast immobilization?
Early systemic administration of avocado/soybean unsaponifiables attenuates nociceptive, vascular, inflammatory, and oxidative disturbances in a rat model of CRPS-I.
Effect estimate: p=0.001, r=0.78 for mechanical allodynia; p<0.001, r=0.84 for temperature asymmetry; p=0.004, r=0.65 for edema
Absolute Event Rate: 30.2% vs 51.45%
p-value: p=<0.05
Background and Object: Complex Regional Pain Syndrome Type I (CRPS-I) is a debilitating condition often triggered by trauma, with early pathophysiology driven by neuroinflammation and oxidative stress. Avocado/soybean unsaponifiables (ASU) possess potent anti-inflammatory and antioxidant properties but have never been tested for CRPS-I prevention. This study investigated the preventive effects of early systemic administration of ASU on the development of CRPS-I-like features in a validated rat model of tibial fracture and cast immobilization. Methods: Twenty adult male Wistar rats were randomized into two groups (n = 10/group): a CRPS-I (Vehicle) group receiving daily intraperitoneal saline, and a CRPS-I+ASU group receiving daily ASU (300 mg/kg/day). The model was induced via a right tibial fracture followed by 28 days of cast immobilization. Treatment began immediately post-fracture. Behavioral outcomes (mechanical allodynia via von Frey, paw edema, temperature asymmetry) were assessed pre-fracture and on day 29. Subsequently, levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and oxidative stress markers (TAS, TOS, OSI) were measured in the ipsilateral hind paw tissue. Results: ASU treatment significantly attenuated the development of CRPS-I-like manifestations. Compared to the vehicle group, the ASU group exhibited a markedly lower median percentage decrease in mechanical withdrawal threshold (30.20% 22.56–37.01 vs. 51.45% 47.84–61.11, p = 0.001), reduced temperature asymmetry (0.75 °C 0.55–1.00 vs. 1.95 °C 1.80–2.33, p < 0.001), and less paw edema (8.35% 7.06–11.29 vs. 14.75% 12.66–19.20, p = 0.004). Biochemically, ASU treatment significantly suppressed tissue levels of IL-1β, IL-6, and TNF-α (all p < 0.001), enhanced total antioxidant status (TAS), and reduced total oxidant status (TOS) and the oxidative stress index (OSI) (all p < 0.001). Conclusions: Early systemic administration of ASU significantly prevents the development of nociceptive, vascular, inflammatory, and oxidative disturbances in a rat model of CRPS-I. These findings highlight ASU’s multimodal protective effects at the tissue level and position it as a promising candidate for early preventive intervention in post-traumatic CRPS-I.
Karasu et al. (2026) studied Adult male Wistar albino rats with tibial fracture and cast immobilization modeling complex regional pain syndrome type I (CRPS-I) (n=20). Avocado/soybean unsaponifiables (ASU) vs. Vehicle (0.9% saline intraperitoneally) was evaluated on Development of CRPS-I-like features assessed by mechanical withdrawal threshold decrease (%), temperature asymmetry (°C), paw edema (%) (p=0.001, r=0.78 for mechanical allodynia; p<0.001, r=0.84 for temperature asymmetry; p=0.004, r=0.65 for edema, p=<0.05). Avocado/soybean unsaponifiables administered at 300 mg/kg/day intraperitoneally significantly reduced mechanical allodynia percentage decrease from 51.45% to 30.20% (p=0.001), temperature asymmetry from 1.95°C to 0.75°C (p<0.001), and paw edema from 14.75% to 8.35% (p=0.004) in a rat CRPS-I model after 28 days.