Category
Basic
Description
Neuropathic pain is a chronic pain condition resulting from damage to the nervous system which does not respond to current pharmacological treatments. Previous research in rats has demonstrated that formalin injections can induce chronic pain states and molecular changes within the spinal cord comparable to those of the spinal nerve ligation (SNL), an established surgical model of neuropathic pain. This study aimed to determine whether a subcutaneous injection of 5% formalin is sufficient to induce chronic pain in mice, providing a simple and less invasive model to study chronic pain mechanisms. Mechanical pain sensitivity is assessed using the von Frey filament test, in which a series of calibrated filaments is applied in ascending order of force to the plantar surface of the paw, and the withdrawal threshold is recorded as an indicator of mechanical sensitivity. Mice receiving formalin exhibited a significantly lower withdrawal threshold compared to the vehicle-treated group, indicating heightened mechanical sensitivity and suggesting the development of chronic formalin-induced hyperalgesia. These findings suggest that a single subcutaneous injection of 5% formalin can provide a reproducible, less invasive method to study chronic pain in mice.
Quantifying Neuropathy with Von Frey Filaments in Mice: Novel Neuropathic Pain Animal Model
Basic
Neuropathic pain is a chronic pain condition resulting from damage to the nervous system which does not respond to current pharmacological treatments. Previous research in rats has demonstrated that formalin injections can induce chronic pain states and molecular changes within the spinal cord comparable to those of the spinal nerve ligation (SNL), an established surgical model of neuropathic pain. This study aimed to determine whether a subcutaneous injection of 5% formalin is sufficient to induce chronic pain in mice, providing a simple and less invasive model to study chronic pain mechanisms. Mechanical pain sensitivity is assessed using the von Frey filament test, in which a series of calibrated filaments is applied in ascending order of force to the plantar surface of the paw, and the withdrawal threshold is recorded as an indicator of mechanical sensitivity. Mice receiving formalin exhibited a significantly lower withdrawal threshold compared to the vehicle-treated group, indicating heightened mechanical sensitivity and suggesting the development of chronic formalin-induced hyperalgesia. These findings suggest that a single subcutaneous injection of 5% formalin can provide a reproducible, less invasive method to study chronic pain in mice.
