Danggui Buxue Decoction Alleviates Inflammation and Oxidative Stress in Mice with Escherichia coli-Induced Mastitis

Abstract

(1) Background: Bovine mastitis is a lactational disease caused by infection and milk stagnation in the mammary glands. Danggui buxue decoction (DBD), a traditional remedy for blood tonification, anti-inflammation, and antioxidation, has not been used previously to treat mastitis. (2) Methods: In this study, an Escherichia coli mastitis model was established by infecting lactating Kunming mice with clinically isolated bovine mastitis-derived E. coli. Based on this, the effects of DBD on inflammation and oxidative stress in mastitis model mice were evaluated by conducting routine blood tests, H&E staining, qRT-PCR analysis, ELISA, and microcolorimetry. (3) Results: We found that DBD treatment reduced body weight loss, abnormal organ indices, abnormal blood cell counts, pathological damage to breast tissue, and the upregulation of the expression of inflammatory factor in mice caused by E. coli infection. We also found that DBD increased the expression of antioxidants and antioxidant genes and decreased the expression of oxidation products and oxidation-related genes in breast tissue. The therapeutic effect of DBD on inflammation and oxidative stress (OS) in mice occurred through the regulation of the TLR4/NF-κB and Nrf2/HO-1 signaling pathways. (4) Conclusions: DBD imparted its anti-inflammatory and antioxidant effects by inhibiting the TLR4/NF-κB signaling pathway and activating the antioxidant Nrf2/HO-1 signaling pathway.

Keywords: Danggui buxue decoction (DBD); Escherichia coli (E. coli) mastitis; inflammation; oxidative stress (OS).

Figure 1

Herbs used to make the DBD are shown. (A) Angelica sinensis; (B) Astragalus membranaceus.

Figure 2

Establishment of a mouse mastitis model induced by E. coli and a sample acquisition scheme.

Figure 3

Experimental protocol for DBD treatment of mastitis in mice and sample collection.

Figure 4

Appearance and internal organs of the mice. (A,B) Control group; (C,D) Model group; (E) Liver and spleen of the mice.

Figure 5

Escherichia coli-induced mastitis in mice. (A) Hematological parameters of the mice; (B) H&E staining (100×), (a,b) Control group, (c,d) Model group; (C) Cytokine levels in the serum; (D) Relative mRNA expression in the mouse mammary tissue. “*” indicates p < 0.05 compared with the control group, and “**” indicates p < 0.01 compared with the control group.

Figure 6

Weight and Organ index. (A) Percentage weight reduction = (starting weight − end weight)/starting weight − 100%; (B) Organ index = Organ index weight (mg)/body weight (g) × 100%. “**” indicates p < 0.01 compared with the control group. “##” indicates p < 0.01 compared with the model group.

Figure 7

Hematological parameters of the mice. (A) Lym; (B) Mon%; (C) RBCs; (D) HGB. “*” indicates p < 0.05 compared with the control group, and “**” indicates p < 0.01 compared with the control group. “##” indicates p < 0.01 compared with the model group.

Figure 8

Eye view and H&E staining (100×). (A–C) Control group; (D–F) Mastitis group; (G–I) DBD group.

Figure 9

ELISA was performed to determine the levels of TNF-α and IL-1β in the serum. (A) TNF-α; (B) IL-1β. “**” indicates p < 0.01 compared with the control group. “##” indicates p < 0.01 compared with the model group.

Figure 10

Levels of inflammatory factors in mammary tissues. (A) ELISA; (B) qRT-PCR. “**” indicates p < 0.01 compared with the control group. “#” indicates p < 0.05 compared with the model group and “##” indicates p < 0.01 compared with the model group.

Figure 11

The effect of DBD on the TLR4/NF-κB signaling pathway. (A) mRNA levels; (B) protein levels; (C) gray analysis. “**” indicates p < 0.01 compared with the control group. “##” indicates p < 0.01 compared with the model group.

Figure 12

Oxidative and antioxidant indices in mouse mammary tissues. (A) T-AOC of mammary tissues; (B) GSH content of mammary tissues; (C) SOD activity of mammary tissues; (D) MDA content of mammary tissues; (E) NO level in serum; (F,G) relative mRNA levels of COX-2 and PPARγ. “**” indicates p < 0.01 compared with the control group. “#” indicates p < 0.05 compared with the model group and “##” indicates p < 0.01 compared with the model group.

Figure 13

The effect of DBD on the Nrf2/HO-1 signaling pathway. (A) mRNA levels; (B) protein levels; (C) gray analysis. “*” indicates p < 0.05 compared with the control group, and “**” indicates p < 0.01 compared with the control group. “##” indicates p < 0.01 compared with the model group.