Effect of electroacupuncture on the intestinal microflora in rats with stress urinary incontinence

Abstract

Objective: To examine the effect of electroacupuncture on the urodynamics and gut microbiota of rats with stress urinary incontinence (SUI).

Materials and methods: Thirty 2-month-old female Sprague-Dawley (SD) rats were randomly assigned to 4 groups: normal (N), model (M), nonacupoint electric acupuncture control (NAAC), and electroacupuncture (EA). An SUI rat model was established through vaginal balloon dilatation and bilateral oophorectomy. After various treatments, urodynamic tests were performed, and feces were collected. 16S rRNA sequencing analysis was used to investigate SUI-related changes in the intestinal flora.

Results: After treatment, compared with those of the M group, the leak point pressure and maximum bladder capacity of the electroacupuncture groups increased (P<0.05). The species community compositions of the N and M groups differed at the genus level, and there were 15 differentially abundant bacterial genera (P<0.05). The Blautia proportion was increased by electroacupuncture treatment (P<0.05) and was significantly positively correlated with the electroacupuncture treatment of SUI (according to Spearman correlation analysis).

Conclusion: Electroacupuncture treatment can improve signs of urine leakage in rats with SUI rats by increasing the leak point pressure and maximum bladder capacity. The enrichment of Blautia by electroacupuncture treatment enrichment may be related to SUI sign improvement.

Keywords: blautia; electroacupuncture; intestinal flora; stress urinary incontinence; urodynamics.

Figure 1

The effects of EA on LPP (A, B) and MBC (C, D) in rats with SUI (N=6, M=5, NAAC=6, EA=6). (A) The LPP before treatment was analyzed via one-way analysis of variance (ANOVA) (F (3,19) = 27.702, P=0.001 <0.05), followed by pairwise comparison using the least significant difference (LSD) test. (B) The LPP after treatment was analyzed via ANOVA (F (3,19) = 19.551, P=0.001 <0.05), followed by pairwise comparison using the LSD test. (C) The MBC before treatment was analyzed via ANOVA (F (3,19) = 8.515, P=0.001 <0.05), followed by pairwise comparison using the LSD test. (D) The MBC after treatment was analyzed via ANOVA (F (3,19) = 3.455, P=0.037 <0.05), followed by pairwise comparison using the LSD test. *P < 0.05 compared with the N group; ^# P < 0.05 compared with the M group.

Figure 2

Diversity of the microbial community associated with the rats in each group. Alpha rarefaction curve (A, B) and violin plot analysis (C, D). The alpha index rarefaction curves show the differences in species abundance among samples and evaluate the rationality of the sequencing quantity of samples. Violin plot analysis of alpha diversity using the Kruskal–Wallis test reflected the dispersion degree of samples in the group and the intergroup index differences. The Chao1 index (A, C) reflected richness, and the Shannon (B, D) index considered diversity. (E) Beta diversity (PLS-DA) of the four groups, showing the similarities and differences in species composition among different individuals or groups. The results demonstrated that there were differences in the composition of the four groups.

Figure 3

Community bar plot analysis showing the flora community composition at the genus level. The dominant bacteria in the N group and the EA group were the same, namely, Bacteroides and norank_f_Muribaculaceae (A). The Kruskal–Wallis rank-sum test bar plot shows the top 15 species with the most abundant expression at the genus level (B). *0.01< P <=0.05, **0.001< P <=0.01. The relative abundance of Blautia in each group was analyzed via the Kruskal–Wallis test (H = 12.110, P=0.007, <0.05) (C). *P < 0.05 compared with the N group; ^#P < 0.05 compared with the M group.

Figure 4

The LDA score identified the size differentiation between the N and M groups with a threshold value of 2. *0.01< P ≤0.05. The relative abundances of the Allobaculum and A2 genera in the M group increased, while the relative abundances of Bacteroides, Bacteroidaceae, Blautia, f_norank_o_Rhodospirillales, norank_o_Rhodospirillales Anaerostipes, g_Ruminiclostridium_1, g_Candidatus_Soleaferrea, g_GCA_900066225, Erysipelatoclostridium, Holdemania, Burkholderiaceae, and g_Marvinbryantia decreased (LDA = 2.0, P <0.05).

Figure 5

Correlation analysis between urodynamics and different genera. Correlation analysis between MBC, LPP and the major genera. The analysis was conducted using Spearman’s test. Red represents a positive correlation, and blue represents a negative correlation; the deeper the color is, the stronger the correlation (*0.01< P ≤0.05, **0.001< P ≤0.01).