Despite numerous efforts to overcome
neuropathic pain, various pharmacological drugs often fail to meet the needs and have many side effects.
Muscovite is an
aluminosilicate mineral that has been reported to have an anti-inflammatory effect, but the efficacy of
muscovite for
neuropathic pain has not been investigated. Here, we assessed whether
muscovite nanoparticles can reduce the symptoms of
pain by controlling the inflammatory process observed in
neuropathic pain. The
analgesic effects of
muscovite nanoparticles were explored using partial sciatic nerve
ligation model of
neuropathic pain, in which one-third to one-half of the nerve trifurcation of the sciatic nerve was tightly tied to the dorsal side.
Muscovite nanoparticles (4 mg/100 μL) was given intramuscularly to evaluate its effects on
neuropathic pain (3 days per week for 4 weeks). The results showed that the
muscovite nanoparticle
injections significantly alleviated partial sciatic nerve
ligation-induced mechanical and cold
allodynia. In the spinal cord, the
muscovite nanoparticle
injections exhibited inhibitory effects on astrocyte and microglia activation and reduced the expression of pro-inflammatory
cytokines, such as interleukin-1β,
tumor necrosis factor-α, interleiukin-6 and
monocyte chemoattractant protein-1, which were upregulated in the partial sciatic nerve
ligation model. Moreover, the
muscovite nanoparticle
injections resulted in a decrease in
activating transcription factor 3, a neuronal injury marker, in the sciatic nerve. These results suggest that the
analgesic effects of
muscovite nanoparticle on partial sciatic nerve
ligation-induced
neuropathic pain may result from inhibiting activation of astrocytes and microglia as well as pro-inflammatory
cytokines. We propose that
muscovite nanoparticle is a potential anti-nociceptive candidate for
neuropathic pain. All experimental protocols in this study were approved by the Institutional Animal Ethics Committee (IACUC) at Dongguk University, South Korea (approval No. 2017-022-1) on September 28, 2017.