Neuropathic pain responds poorly to
drug treatments, and partial relief is achieved in only about half of the patients.
Puerarin, the main constituent of Puerariae Lobatae Radix, has been used extensively in China to treat
hypertension and
tumor. The current study examined the effects of
puerarin on
neuropathic pain using two most commonly used animal models: chronic constriction injury (CCI) and
diabetic neuropathy. We found that consecutive intrathecal administration of
puerarin (4-100 nM) for 7 days inhibited the mechanical and thermal nociceptive response induced by CCI and diabetes without interfering with the normal
pain response. Meanwhile, in both models
puerarin inhibited the activation of microglia and astroglia in the spinal dorsal horn.
Puerarin also reduced the upregulated levels of nuclear factor-κB (NF-κB) and other proinflammatory
cytokines, such as
IL-6, IL-1β, and TNF-α, in the spinal cord. In summary,
puerarin alleviated CCI- and diabetes-induced
neuropathic pain, and its effectiveness might be due to the inhibition of
neuroinflammation in the spinal cord. The anti-
inflammation effect of
puerarin might be related to the suppression of spinal NF-κB activation and/or
cytokines upregulation. We conclude that
puerarin has a significant effect on alleviating
neuropathic pain and thus may serve as a therapeutic approach for
neuropathic pain.