Fig. 5

Effects of glycyrrhizin on the systemic inflammatory response and neuroinflammation following surgery. a Glycyrrhizin (10, 20, or 40 mg/kg, once) were administered i.p. 30 min before and 12 h after surgery, and the serum HMGB1 concentration was measured using ELISA on postoperative day 1 (n = 6 rats per group). The serum b IL-1β and c IL-6 concentrations were measured using ELISAs on postoperative day 1 (n = 6 rats per group). d Two modes of glycyrrhizin injections (2 doses: − 30 min, + 12 h; 5 doses: − 30 min, + 12 h, + 24 h, + 48 h, and + 72 h) were administered, and the serum HMGB1 levels were measured using ELISA on postoperative day 3 (n = 6 rats per group). e Inset of the glycyrrhizin treatment regimen and pharmacological analysis protocol. f Representative immunoblots and corresponding densitometry analysis of HMGB1 protein levels in the dHPC on postoperative day 3 (n = 6 rats per group). g Representative confocal images of immunohistochemical staining for HGMB1⁺ cells in the dHPC on postoperative day 3 captured with a 10 × objective. The concentration of h IL-1β and i IL-6 in the dHPC were measured using ELISAs on postoperative day 1 (n = 6 rats per group). j Representative confocal images of immunohistochemical staining for Iba1⁺ cells in the dHPC captured with a 10 × objective (left panel) and quantitative analysis on postoperative day 3 (n = 6 rats per group, right panel). k Sholl quantitative analysis of microglial process complexity. l Total process lengths and m cell body area of microglia were analyzed using FIJI software (n = 96 microglial cells from 4 rats per group). GLY: glycyrrhizin, C: control, S: surgery. Data are presented as means ± SEM and statistical analyzed by a Student’s t test (a, d) or a one-way ANOVA followed by a Tukey’s test (b, c, f, h, i, j, k, l, and m). *p < 0.05, **p < 0.01, and ***p < 0.001 compared with Control-saline; ^#p < 0.05, ^##p < 0.01, and ^###p < 0.001 compared with Surgery-saline