Priestia megaterium ASC-1 Isolated from Pickled Cabbage Ameliorates Hyperuricemia by Degrading Uric Acid in Rats

Abstract

Pickled cabbage, a traditional fermented food rich in functional microorganisms, can effectively control hyperuricemia and gout. In this study, a Priestia megaterium ASC-1 strain with strong uric acid (UA) degradation ability was isolated from pickled cabbage. After oral administration for 15 days, ASC-1 was stably colonized in the rats in this study. ASC-1 significantly reduced UA levels (67.24%) in hyperuricemic rats. Additionally, ASC-1 alleviated hyperuricemia-related inflammatory response, oxidative stress, and blood urea nitrogen. Intestinal microbial diversity results showed that ASC-1 restored intestinal injury and gut flora dysbiosis caused by hyperuricemia. These findings suggest that P. megaterium ASC-1 may be used as a therapeutic adjuvant for the treatment of hyperuricemia.

Keywords: Priestia megaterium; gut microbiota; hyperuricemia; uric acid.

Figure 1

The screening and identification of ASC-1 strain. (a) Scanning electron microscopy (SEM) images of the ASC-1 strain. (b) Construction of a phylogenetic tree of the ASC-1 strain and related bacterial species. (c) The influence of different culture media on the growth of strains ASC-1, S-1, and S-2. Compared with the medium without uric acid, the three strains grew better in the medium containing UA, and ASC-1 had the best growth effect in the medium containing UA. (d) Agarose gel electrophoresis for the identification of isolated strains. Line 1: Marker DL5000; lines 2–4: 16S rDNA amplified from strains ASC-1, S-1, and S-2.

Figure 2

Detection of uric acid degradation products by ASC-1 strain. (a) The ability of ASC-1 to degrade UA in vitro. (b) Detection peak of inosine standard. (c) Detection of inosine degradation products by ASC-1 using high-performance liquid chromatography (HPLC). (d) Detection of inosine degradation products by S-1. (e) Detection of inosine degradation products by S-2. The bar graph shows the mean ± standard deviation (n = 3 samples per group). **** p < 0.0001, indicating statistically significant differences.

Figure 3

Effect of ASC-1 on hyperuricemia rats. (a) Flow chart of the experimental treatment of hyperuricemia rats with ASC-1. (b) Colonization of ASC-1 was detected by PCR on days 4, 8, and 12. (c) The proportion of ASC-1 in fecal flora was determined by qPCR on day 12. (d) The amount of UA in urine after 14 days. (e) Serum UA of rats after 14 days. Bar chart shows mean ± SD (n = 3 rats per group) * p < 0.1; ** p < 0.01, *** p < 0.001, **** p < 0.0001.

Figure 4

Effects of ASC-1 on inflammatory markers and oxidative stress indicators in hyperuricemia rats. (a–d) The levels of IL-1β, MDA, CRE, and BUN of rats from each group. (e–h) The levels of IL-1β and MDA in livers and kidneys of rats from each group. (i) Representative micrographs of liver and kidney tissues stained with hematoxylin and eosin (H&E). The bar graph displays the mean ± standard deviation for 5 rats in each group. Statistical significance was observed with * p < 0.1; ** p < 0.01; *** p < 0.001, and ns p > 0.05. The microscope magnification is 200 × Bar = 100 μm.

Figure 5

The impact of ASC-1 and allopurinol treatment on the functionality and diversity of the intestinal microbiota in rats exposed to UA. (a) The fecal microbiota from various groups of rats, indicating their ability to degrade UA. (b) The concentrations of short-chain fatty acids in the feces of these groups. (c) Principal Coordinate Analysis (PCoA). (d) Comparison of relative abundances at the phylum level among different groups. (e) Comparison of relative abundances of the most abundant bacterial genera among the four groups. (f,g,i) Comparison of relative abundances of significantly changed bacterial phyla (Firmicutes, Verrucomicrob, and Bacteroidetes). (h) Verru/Firm ratio (the ratio of Verrucomicrob to Firmicutes) for each group. (j) Analysis of the overlap of microbial OTUs (operational taxonomic units) among different groups using Venn diagrams. Bar graphs show the mean ± standard deviation of data from 3 rats in each group. * p < 0.1; ** p < 0.01; *** p < 0.001 indicate statistically significant differences.