Anti-inflammatory Effect of Mesenchymal Stromal Cell Transplantation and Quercetin Treatment in a Rat Model of Experimental Cerebral Ischemia

Abstract

Here, we have investigated the synergistic effect of quercetin administration and transplantation of human umbilical cord mesenchymal stromal cells (HUMSCs) following middle cerebral artery occlusion in rat. Combining quercetin treatment with delayed transplantation of HUMSCs after local cerebral ischemia significantly (i) improved neurological functional recovery; (ii) reduced proinflammatory cytokines (interleukin(IL)-1β and IL-6), increased anti-inflammatory cytokines (IL-4, IL-10, and transforming growth factor-β1), and reduced ED-1 positive areas; (iii) inhibited cell apoptosis (caspase-3 expression); and (iv) improved the survival rate of HUMSCs in the injury site. Altogether, our results demonstrate that combined HUMSC transplantation and quercetin treatment is a potential strategy for reducing secondary damage and promoting functional recovery following cerebral ischemia.

Keywords: Apoptosis; Inflammation; Mesenchymal stromal cells; Quercetin; Stroke.

Fig. 1

Schedule for investigating the effect of HUMSCs and quercetin on neurological function in an animal model of ischemic stroke

Fig. 2

Morphology and identification of HUMSCs. HUMSC appearance in the primary (a) and fourth (b) passages. Immunophenotypic analysis of cultured HUMSCs (c). Osteogenic (d) and adipogenic (e) differentiation potential of HUMSCs. Scale bar shown in (a). a, b = 100 µm; c, d = 50 µm

Fig. 3

Functional evaluation after HUMSC transplantation. The HUMSCs + Qu-treated group shows improved functional recovery, as shown by the rotarod test (a) and mNSS score (b), compared with the HUMSCs or Qu groups alone. n = 6, *p < 0.05, **p < 0.01, compared with the same day saline group; ^# p < 0.05 compared between groups, n = 6

Fig. 4

HUMSCs and quercetin decreases infarct volume. a Brain sections stained with TTC to visualize the ischemic lesion at 28 days. b Quantitative analysis of the infarct volume. Data are expressed as mean ± SD. Scale bar = 10 mm, n = 4

Fig. 5

Very few CD11b-positive microglials were observed around the injury epicenter in both HUMSCs and HUMSCs + Qu group at 7 days post injury (a). Survival rate of HUMSCs. b, c Quantitative analysis of survival number in the HUMSCs + Qu group was significantly higher than in the HUMSCs group at 7 and 28 days post transplantation. d Immunoreactive staining of specific neural marker-positive cells after 28 days post transplantation. *p < 0.05, compared with the HUMSCs group. Scale bar shown in (a). a = 200 µm, c = 100 µm, n = 75

Fig. 6

Anti-inflammatory effect in the HUMSCs + Qu group. The levels of IL-4 (a), IL-6 (b), TGF-β1 (c), IFN-γ (d), IL-1β (e), and IL-10 (f) were analyzed. *p < 0.05, **p < 0.01, and ***p < 0.001 compared with the same day saline group; ^# p < 0.05, ^## p < 0.01, and ^### p < 0.001 compared between the HUMSCs + Qu group (or HUMSCs group) and Qu group; ^{^} p < 0.05, ^{^^} p < 0.01, and ^{^^^} p < 0.001 compared between the HUMSCs + Qu and HUMSCs groups, n = 12

Fig. 7

Anti-apoptotic effect in the HUMSCs + Qu group. ED-1 and caspase-3 immunoreactive staining (a–d, f–i). Quantitative analysis of ED-1 positive area (e) and caspase-3-positive cell number (j). Scale bar shown in a = 50 µm, n = 4