Decoction derived from Allium ascalonicum L. bulbs and Sojae Semen Praeparatum alleviates wind-cold-type common cold via Nrf2/HO-1 pathway and modulation of Lactobacillus murinus level

Abstract

Background: Cong-Chi decoction (CCD) is made using Allium ascalonicum L. (shallot) bulbs and Sojae Semen Praeparatum (SSP). Shallot bulbs and SSP are both used regularly in traditional Chinese medicine; however, there are no recent pharmacological studies on their synergistic effects. Despite their roles in the treatment of the common cold for thousands of years, their pharmacological mechanisms of action against wind-cold-type common cold are yet to be explored comprehensively.

Methods: A mouse model was standardized using wind-cold modeling equipment to study the anti-inflammatory, antioxidant, and antiapoptotic effects of CCD. Then, 16S rRNA sequencing was employed to analyze the association between Lactobacillus murinus and changes in body temperature. Additionally, the antipyretic effects of L. murinus were validated via animal experiments.

Results: The results indicate that CCD improves the symptoms of wind-cold by reducing fever, levels of pro-inflammatory factors, and cellular apoptosis, as well as increasing the blood leukocyte and lymphocyte counts, thereby alleviating lung tissue damage. The effects of CCD are mediated by upregulation of pulmonary Nrf2 and HO-1 expressions, thereby reducing oxidative damage in the lungs, in addition to other anti-inflammatory mechanisms. Furthermore, CCD increases the abundance of L. murinus in the intestinal tract. The animal experiments confirm that L. murinus ameliorates fever in mice.

Conclusion: CCD exhibits remarkable antioxidant and anti-inflammatory properties for effectively treating wind-cold-type common cold. Furthermore, its regulatory effects on L. murinus represent a novel mechanism for product development.

Keywords: Allium ascalonicum L. bulbs; Lactobacillus murinus; Glycine max (L.) Merr; Nrf2/HO-1 pathway; Sojae Semen Praeparatum; wind-cold-type common cold.

FIGURE 1

Experimental groups and associated therapies.

FIGURE 2

Effects of CCD on body temperature and hypothalamic cAMP and PGE2: (A) temporal profile illustrating changes in the body temperatures of mice in each group over a 7-day period (n = 6); (B, C) CCD administration resulted in significant inhibition of cAMP and PGE2 secretions in the hypothalamic tissues of the model mice (n = 5). All data are expressed as the mean ± standard error of the mean. ^## p < 0.01 and ^### p < 0.001 compared with the blank group. *p < 0.05, **p < 0.01, and ***p < 0.001 compared with the model group.

FIGURE 3

Effects of CCD on inflammatory factors in the lung tissues of BALb/c mice. CCD administration resulted in the suppression of TNF-α, IL-6, and IL-1β secretions in the lung tissues of model mice (n = 6). Secretions of (A) IL-6, (B) TNF-α, and (C) IL-1β. All data are expressed as the mean ± standard error of the mean. ^### p < 0.001 compared with the blank group. ***p < 0.001 compared with the model group.

FIGURE 4

Effects of CCD on hematological indices. CCD increased the white blood cell count and lymphocyte ratio in the model mice (n = 6). Changes in the (A) white blood cell count and (B) lymphocyte ratio. All data are expressed as the mean ± standard error of the mean. ^### p < 0.001 compared with the blank group. *p < 0.05, and ***p < 0.001 compared with model group.

FIGURE 5

Effects of CCD on lung histopathology in mice in the (A) blank group (H&E, × 80) and (B) model group (H&E, × 80), demonstrating neutrophil infiltration (round arrow), hemorrhage (flat arrow), compensatory vacuole (striped arrow), and interstitial proliferation (dashed arrow). Corresponding lung histopathologies in the (C) positive group (H&E, × 80), (D) low-dose group (H&E, × 80), (E) medium-dose group (H&E, × 80), and (F) high-dose group (H&E, × 80). The histological sections were stained with hematoxylin and eosin (H&E) to visualize tissue morphology at ×80 magnification.

FIGURE 6

Effects of CCD showing inhibition of cellular apoptosis of the lungs and spleen (n = 3). Flow cytometry scatterplots of (A) mouse lung cells and (B) spleen cells. All data are expressed as the mean ± standard error of the mean. ^### p < 0.001 compared with the blank group. ***p < 0.001 compared with the model group.

FIGURE 7

CCD treatment increased the expressions of Nrf2 and HO-1 in the lung tissues of BALb/c mice (n = 3): (A–C) immunohistochemistry, (D–E) quantitative real-time PCR, and (F–H) Western blot results showing the effects of CCD on the expressions of Nrf2 and HO-1 in the lung tissues of BALb/c mice. Scale bar: 50 µm. All data are expressed as the mean ± standard error of the mean. ^# p < 0.05, ^## p < 0.01, and ^### p < 0.001 compared with blank group *p < 0.05, **p < 0.01, and ***p < 0.001 compared with the model group.

FIGURE 8

Effects of CCD on the gut microbiota (n = 5). (A) Unweighted UniFrac principal coordinates analysis (PCoA) based on OTUs. (B) Percentage of community abundance at the species level. (C) Top 15 abundant species showing differences in abundance in the blank, model, high-dose, medium-dose, and low-dose groups. (D) Heatmap showing hierarchical clustering between the fecal bacterial abundance and body temperatures of mice using the Spearman correlation coefficient. (E) Heatmap showing hierarchical clustering between the fecal bacterial abundance and selected cytokine levels using Spearman correlation coefficient. (F) LEfSe was employed to analyze the dominant bacteria at various taxonomic levels (from order to species) among the five groups. The Kruskal–Wallis test was used to evaluate statistical significance between the groups for non-parametric data. The Spearman correlation coefficient test was applied to explore the relationships between the gut microbiota and body temperatures. The significance level was set at *p < 0.05, **p < 0.01, and ***p < 0.001.

FIGURE 9

Effects of L. murinus on body temperature and hypothalamic cAMP and PGE2 levels. (A) Changes in the body temperatures of mice in each group over 7 days (n = 6). (B, C) L. murinus inhibited the secretions of cAMP and PGE2 in the hypothalamic tissues of the model mice (n = 9). All data are expressed as the mean ± standard error of the mean. ^# p < 0.05, ^## p < 0.01, and ^### p < 0.001 compared with the blank group. ***p < 0.001 compared with the model group.