Thymoquinone Ameliorates Lung Inflammation and Pathological Changes Observed in Lipopolysaccharide-Induced Lung Injury

Abstract

Anti-inflammatory, antioxidant, and immunomodulatory effects of thymoquinone (TQ) have been shown. The effects of TQ on lipopolysaccharide- (LPS-) induced inflammation and pathological changes in rats' lung were investigated in this study. Four groups of rats included (1) control (saline treated); (2) LPS (treated with 1 mg/kg/day i.p. for two weeks); and (3 and 4) 5 or 10 mg/kg TQ i.p. 30 min prior to LPS administration. Total and differential WBC counts in the blood and bronchoalveolar fluid (BALF), TGF-β1, INF-γ, PGE2, and IL-4 levels in the BALF and pathological changes of the lung were evaluated. Total WBC count and eosinophil, neutrophil, and monocyte percentage were increased, but the lymphocyte percentage was reduced in the blood and BALF. The BALF levels of PGE2, TGF-β1, and INF-γ were also increased, but IL-4 level was reduced due to LPS administration. LPS also induced pathological insults in the lung of rats (P < 0.05 to P < 0.001 for all changes in LPS-exposed animals). Treatment with TQ showed a significant improvement in all changes induced by LPS (P < 0.05 to P < 0.05). TQ showed a protective effect on LPS-induced lung inflammation and pathological changes in rats which suggested a therapeutic potential for TQ on lung injury.

Figure 1

Total white blood cell count (a) and percent of neutrophils (b) in blood. Data are presented as means  ±  SEM (n = 6 in each group). ^∗∗∗P < 0.001 vs. control group; ⁺⁺⁺P < 0.001 vs. LPS group. For comparison between groups, one-way analysis of variance (ANOVA) with Tukey multiple comparison tests was used.

Figure 2

Percentages of monocyte (a), eosinophil (b), and lymphocytes (c) in blood. Data are presented as means ± SEM (n = 6 in each group). ^∗∗∗P < 0.001 vs. control group; ⁺P < 0.05, ⁺⁺P < 0.01, and ⁺⁺⁺P < 0.001 vs. LPS group. For comparison between groups, one-way analysis of variance (ANOVA) with tukey multiple comparison tests was used.

Figure 3

Total white blood cell count (a) and percent of neutrophils (b) in the BALF. Data are presented as means ± SEM (n = 6 in each group). ^∗∗P < 0.01 vs. control group; ⁺P < 0.05 vs. LPS group. For comparison between groups, one-way analysis of variance (ANOVA) with tukey multiple comparison tests was used.

Figure 4

Percentages of monocyte (a), eosinophil (b), and lymphocytes (c) in the BALF. Data are presented as means ± SEM (n = 6 in each group). ^∗P < 0.05, ^∗∗∗P < 0.001 vs. control group, and ⁺P < 0.05, ⁺⁺P < 0.01, and ⁺⁺⁺P < 0.001 vs. LPS group. For comparison between groups, one-way analysis of variance (ANOVA) with tukey multiple comparison tests was used.

Figure 5

The concentrations of TGF-β1 (a) and PGE2 (b) in the BALF. Data are presented as means ± SEM (n = 6 in each group). ^∗∗∗P < 0.001 vs. control group; ⁺⁺⁺P < 0.001 vs. LPS group. For comparison between groups, one-way analysis of variance (ANOVA) with Tukey multiple comparison tests was used.

Figure 6

The concentrations of IL-4 (a) and INF-γ (b) in the tissue. Data are presented as means ± SEM (n = 6 in each group). ^∗∗∗P < 0.001 vs. control group; ⁺⁺⁺P < 0.001 vs. LPS group. For comparison between groups, one-way analysis of variance (ANOVA) with tukey multiple comparison tests was used.

Figure 7

Epithelial damage (a) and emphysema (b) scores of lung tissue. Data are presented as means ± SEM (n = 6 in each group). ^∗∗P < 0.01 vs. control group; ⁺⁺P < 0.01 vs. LPS group. For comparison between groups, one-way analysis of variance (ANOVA) with tukey multiple comparison tests was used.

Figure 8

Intestinal inflammation (a), fibrosis (b), and hemorrhage (c) scores of lung tissue. Data are presented as means ± SEM (n = 6 in each group). ^∗P < 0.05 and ^∗∗∗P < 0.001 vs. control group; ⁺⁺P < 0.01 and ⁺⁺⁺P < 0.001 vs. LPS group. For comparison between groups, one-way analysis of variance (ANOVA) with Tukey multiple comparison tests was used.

Figure 9

Representative photographs of pathological changes of lung in LPS-induced lung in the control group (a), LPS-exposed group (b), and LPS-exposed and -treated animals with low (c) and high (d) doses of TQ (hematoxylin and eosin staining, magnification 200x).