Long-term outcomes of monascin - a novel dual peroxisome proliferator-activated receptor γ/nuclear factor-erythroid 2 related factor-2 agonist in experimental intracerebral hemorrhage

Abstract

Background: Hematoma is the chief culprit in brain injury following intracranial cerebral hemorrhage (ICH). Noninvasive hematoma clearance could be an option to prevent and alleviate early brain injury after ICH. Peroxisome proliferator-activated receptor γ (PPAR-γ) and nuclear factor-erythroid 2 related factor-2 (Nrf2) facilitate removal of hematoma in ICH. Monascin acts as the natural Nrf2 activator with PPAR-γ agonist, and the long-term effects of monascin following ICH have not been elucidated.

Methods: ICH in rats was induced by stereotactic, intrastriatal injection of type IV collagenase. Monascin was administered twice daily by gastric perfusion for 14 days after ICH induction. Long-term neurological scores (T maze, Garcia scales, rotor rod test, and Morris water maze), hematoma volume, as well as iron overload around hematoma and brain atrophy were evaluated at 7, 14, and 28 days after ICH.

Results: The results showed that monascin improved long-term neurological deficits, spatial memory performance, learning ability, and brain shrinkage after ICH. Monascin also reduced hematoma volume at 7 days and iron content at 7 and 14 days after ICH.

Conclusion: PPAR γ and Nrf2 play a crucial role in hematoma clearance after ICH in rat. As a dual agonist of PPAR γ and Nrf2, monascin improved long-term outcomes by facilitating hematoma clearance, and by attenuating iron overload and brain atrophy after experimental ICH.

Keywords: dual receptor agonist; hematoma clearance; intracerebral hemorrhage; monascin; peroxisome proliferator-activated receptor γ/nuclear factor-erythroid 2 related factor-2.

Figure 1.

The T-maze consisted of a gray wooden startbox flanked on either side by a wooden choice chamber. The left compartment was painted white and the right side was black. One-way doors made of clear plastic permitted entry into the choice chambers and prevented retracing. The lids of all chambers were made of clear plastic and the floors of hardware cloth.

Figure 2.

Morris water maze test was applied in all groups from 25 to 28 days after ICH (n = 6/group). (a) Visualization of the swimming track and heat map. (b) Mean latency to escape onto the platform. (c) Mean swimming distances before escaping onto the platform. and (d) Mean platform searching times within the target quadrant. *p < 0.05 versus sham, #p < 0.05 versus ICH+vehicle, 2-way ANOVA, mean ± SD, analysis by repeated measures ANOVA. ANOVA, analysis of variance; ICH, intracranial cerebral hemorrhage; SD, standard deviation.

Figure 3.

Hemorrhage slices (a) and hemoglobin levels (b) at 7, 14, and 28 days after ICH. To better illustrate the levels of hemoglobin compared with the sham (hematoma is zero), data are showed as a ratio (the preset value of the sham was 1). One-way ANOVA followed by Tukey tests were used. *p < 0.05 versus Sham, #p < 0.05 versus ICH+Vehicle. ANOVA, analysis of variance; ICH, intracranial cerebral hemorrhage.

Figure 4.

(a) Iron staining and (b) iron contents assays at 7, 14, and 28 days after ICH induction. *p < 0.05 versus Sham, #p < 0.05 versus ICH+Vehicle, n = 6/group, One-way ANOVA, Tukey’s multiple comparison test, mean ± SD. ANOVA, analysis of variance; ICH, intracranial cerebral hemorrhage; SD, standard deviation.

Figure 5.

(a) Hematoxylin-eosin staining and (b) brain weight differences between the left and right hemisphere at 7, 14, and 28 days after surgery. *p < 0.05 versus Sham, #p < 0.05 versus ICH+Vehicle, n = 6/group, One-way ANOVA, Tukey’s multiple comparison test, mean ± SD; values were calculated by subtracting weight of the right from the left hemisphere. ANOVA, analysis of variance; ICH, intracranial cerebral hemorrhage; SD, standard deviation.