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Figure 4.. In vivo acute toxicity results of mice after intraperitoneal injection of different Mg content scaffold extract. Extract MEM solutions were prepared by soaking PT, PT5M, PT10M, and PT15M samples in MEM at 37°C for 72 hours. (A) The percentage of live and dead mice 1 hour after intraperitoneal injection of extract MEM. For those mice that survived or dead, corresponding to the scaffold extract they were injected, we grouped them into four groups which were PT/alive (PT/A), PT5M/alive (PT5M/A), PT10M/alive (PT5M/A), and PT15M/dead (PT5M/D) groups. (B) The weight change of live mice 72 hours after intraperitoneal injection of extract MEM. (C) Mg and Ca ion concentrations in serum 1 hour after intraperitoneal injection of extract MEM. Scale bars: 200 μm. (D) H&E staining of heart, and Mg indicator fluorescent staining of heart, liver, and lung. Black arrows indicate loosened cardiac tissues, and white arrows indicate enrichment sites of Mg ions in tissues. (E) The mass ratios of Mg and Ca in different organs at 1 hour after intraperitoneal injection of extract MEM. Data are expressed as the mean ± SD (n = 10-12, 5-6 male and 5-6 female). ^*P < 0.05, ^**P < 0.01, ^***P < 0.001 (one-way analysis of variance followed by Tukey’s post hoc test). “A” stands for alive mice, and “D” means dead mice. Ca: calcium; H&E: haematoxylin and eosin; MEM: serum-free minimum essential medium; Mg: magnesium; PT: poly(lactic-co-glycolic acid)/beta-tricalcium phosphate porous composite scaffolds; PT5M: poly(lactic-co-glycolic acid)/beta-tricalcium phosphate/5 wt% Mg porous composite scaffolds; PT10M: poly(lactic-co-glycolic acid)/beta-tricalcium phosphate/10 wt% Mg porous composite scaffolds; PT15M: poly(lactic-co-glycolic acid)/beta-tricalcium phosphate/15 wt% Mg porous composite scaffolds.