Intrathecal Delivery of Therapeutic Agents

Artesunate (MedChemExpress, HY-N0193, China) was dissolved in 10% dimethyl sulfoxide (DMSO, Sigma-Aldrich, D2650, United States) for i.t. injection. Recombinant CCL21 (Abcam, ab201361, United Kingdom), a neutralizing antibody against CCL21 (anti-CCL21, R&D Systems, AF457, United States) and a neutralizing antibody against TREM2 (anti-TREM2, R&D Systems, 1729-T2, United States), was dissolved in normal saline or 10% DMSO for i.t.; delivery and the doses of these reagents were chosen based on previous reports (Hu et al., 2018 (link); Wang et al., 2020a (link); Zhang et al., 2022 (link)). The intrathecal injection was performed under brief anesthesia of sevoflurane (induction, 3.0%; surgery, 1.5%; Maruishi Pharmaceutical Co., Ltd., Japan) and made between the levels of L₅ and L₆ using a 30-G needle (Donnelly et al., 2021 (link)); 5 μl of the reagent was given when the reflexive tail flick was observed.