CD206+ M2-like macrophages protect against intervertebral disc degeneration partially by targeting R-spondin-2.

OBJECTIVE: This study aimed to explore the specific function of M2 macrophages in intervertebral disc degeneration (IDD). METHODS: Intervertebral disc (IVD) samples from normal (n = 4) and IDD (n = 6) patients were collected, and the expression of M2-polarized macrophage marker, CD206, was investigated using immunohistochemical staining. Nucleus pulposus cells (NPCs) in a TNF-α environment were obtained, and a mouse caudal IVD puncture model was established. Mice with Rheb deletions, specifically in the myeloid lineage, were generated and subjected to surgery-induced IDD. IDD-induced damage and cell apoptosis were measured using histological scoring, X-ray imaging, immunohistochemical staining, and TdT-mediated dUTP nick end labeling (TUNEL) assay. Finally, mice and NPCs were treated with R-spondin-2 (Rspo2) or anti-Rspo2 to investigate the role of Rspo2 in IDD. RESULTS: Accumulation of CD206 in human and mouse IDD tissues was detected. Rheb deletion in the myeloid lineage (RheBcKO) increased the number of CD206+ M2-like macrophages (mean difference 18.6% [15.7-21.6%], P < 0.001), decreased cell apoptosis (mean difference -15.6% [-8.9 to 22.2%], P = 0.001) and attenuated the IDD process in the mouse IDD model. NPCs treated with Rspo2 displayed increased extracellular matrix catabolism and apoptosis; co-culture with a conditioned medium derived from RheBcKO mice inhibited these changes. Anti-Rspo2 treatment in the mouse caudal IVD puncture model exerted protective effects against IDD. CONCLUSIONS: Promoting CD206+ M2-like macrophages could reduce Rspo2 secretion, thereby alleviating experimental IDD. Rheb deletion may help M2-polarized macrophages accumulate and attenuate experimental IDD partially by inhibiting Rspo2 production. Hence, M2-polarized macrophages and Rspo2 may serve as therapeutic targets for IDD.

[Studies on chemical constituents of Clinopodium chinense].

Twenty-eight compounds were isolated and purified from Clinopodium chinense by Sephedax LH-20, ODS, MCI and preparative HPLC. Their structures were identified as apigenin (1), apigenin-7-O-ß-D-glucopyranoside (2), apigenin-7-O-ß-D-glucuronopyranoside (3), thellungianol (4), apigenin-7-O-ß-D-rutinoside (5), luteolin (6), luteolin-4'-O-ß-D-glucopyranoside (7), apigenin-7-O-ß-D-pyranglycuronate butyl ester (8), luteolin-7-O-ß-D-rutinoside (9), luteolin-7-O-ß-D-noehesperidoside (10), acacetin (11), acacetin-7-O-ß-D-glucuronopyranoside (12), buddleoside (13), naringenin (14), pruning (15), nairutin (16), isosakuranetin (17), isosakuranin (18), didymin (19), hesperidin (20), kaempferol (21), quercetin (22), kaempferol-3-O-α-L-rahmnoside (23), p-hydroxycinnamic acid (24), caffeic acid (25), cis-3-[2-[1-(3,4-dihydroxy-phenyl)-1 -hydroxymethyl]-1,3-ben-zodioxol-5-yl]-(E)-2-propenoic acid (26), mesaconic acid (27), gentisic acid 5-O-ß-D-(6'-salicylyl)-glucopyranoside (28). Among them, compounds 7, 9-10, 12, 23, 26-28 were isolated from the Clinopodium for the first time. The protective effects of compounds 1-6, 8-17 and 19 against H2O2-induced H9c2 cardiomyocyte injury were tested, compounds 15 exhibited significantly protective effects. Compared with the cell viability of (62.12±6.18)% in the model, pruning exhibited viabilities of (84.25±7.36)% at 25.0 mg•L⁻¹, respectively, using quercetin as a positive control [cell viability of (84.55±8.26)%, 20 mg•L⁻¹].