Effect of intrathecal exosomes derived from human amniotic fluid on neuropathic pain in mice / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of intrathecal exosomes derived from human amniotic fluid (hAF exo) on neuropathic pain induced by spared nerve injury (SNI) in mice.Methods:Eighteen clean-grade healthy male Kunming mice, aged 7-8 weeks, weighing 30-35 g, were divided into 3 groups ( n=6 each) using a random number table method: sham operation group (Sham group), SNI group, and SNI+ hAF exo group. Spared nerve injury was produced by exposing the sciatic nerve and its branches and ligation and transection of tibial nerve and common fibular nerve in anesthetized mice. Another three mice were selected to develop the model of neuropathic pain after anesthesia. PKH-26 labeled hAF exo 7 μl was intrathecally injected on days 1, 2 and 3 after developing the model. The mice were sacrificed at 10 h after the end of administration, and the uptake of hAF exo by the dorsal horn of the injured lumbar enlargement of the spinal cord was observed with the fluorescence microscope. On 1, 2 and 3 days after developing the model, 1 μg/μl hAF exo 7 μl was intrathecally injected in SNI+ hAF exo group, and PBS 7 μl was intrathecally injected in Sham group and SNI group. The mechanical paw withdrawal threshold (MPWT) was measured at 1 day before and 1, 3, 5 and 7 days after operation. And then the mice were sacrificed after measurement of the pain threshold at 7 days after developing the model, and the ipsilateral lumbar enlargement of the spinal cord was taken for determination of the expression of CD11b, interleukin-1beta (IL-1β) and IL-10 by Western blot. Results:The dorsal horn of the lumbar enlargement of the spinal cord on the injured side could absorb hAF exo with the fluorescence microscope. Compared with Sham group, the MPWT was significantly decreased at 3-7 days after developing the model, the expression of CD11b and IL-1β was up-regulated ( P<0.05), and no significant change was found in the expression of IL-10 in SNI group ( P>0.05). Compared with SNI group, the MPWT was significantly increased at 3-7 days after developing the model, the expression of CD11b and IL-1β was down-regulated, and the expression of IL-10 was up-regulated in SNI+ hAF exo group ( P<0.05). Conclusions:Intrathecal exosomes derived from human amniotic fluid can alleviate neuropathic pain in mice, and the mechanism may be related to mediation of the polarization of microglia from M1 type to M2 type and attenuation of neuroinflammation.