Effect of IDO1 on functional changes in macrophages in vaginal tissues from mouse models of vulvovaginal candidiasis
10.35541/cjd.20240163
- VernacularTitle:IDO1影响外阴阴道念珠菌病小鼠阴道组织中巨噬细胞功能变化的研究
- Author:
Shiqin TANG
1
;
Ruiying HAO
;
Huina HE
;
Yanan TIAN
;
Yanyan XU
;
Xiaojing LI
;
Tingting JING
Author Information
1. 河北工程大学临床医学院，邯郸 056002
- Keywords:
Candida albicans;
Candidiasis, vulvovaginal;
Macrophages;
IDO1;
Host immunity
- From:
Chinese Journal of Dermatology
2024;57(10):931-939
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To analyze functional changes in macrophages in mouse models of vulvovaginal candidiasis (VVC) by modulating indoleamine 2,3-dioxygenase 1 (IDO1) .Methods:Forty specific-pathogen-free female ICR mice were randomly divided into 4 groups using a complete randomization method: a blank group, a VVC model group, a VVC model + 1-methyltryptophan (1-MT) group (referred to as the 1-MT group), a VVC model + interferon-γ (IFN-γ) group (referred to as the IFN-γ group), with 10 mice in each group. Except for the blank group, all the mice were injected subcutaneously with estradiol benzoate oil solution in the abdomen every other day for 6 days prior to modeling to induce pseudoestrus; after successful induction of pseudoestrus, the mice were inoculated vaginally with Candida albicans suspensions at a concentration of 2 × 10 9 CFU/ml once a day for 5 days to establish VVC mouse models, and subcutaneous injections of estradiol benzoate oil solution were continued simultaneously to maintain the pseudoestrus state; 1 day before inoculation with fungal suspensions, mice in the 1-MT group and IFN-γ group were pretreated with 1-MT and IFN-γ respectively, followed by once-daily same intervention for 6 consecutive days; mice in the blank group and VVC model group were intraperitoneally injected with physiological saline solution once a day for 6 consecutive days. On the 5th day of modeling, vaginal conditions in mice were observed and vaginal symptoms were scored; the vaginal lavage fluid was collected for smear microscopy and fungal colony counting; then, the mice were sacrificed, the vaginal tissues were collected and subjected to hematoxylin-eosin (HE) staining and periodic acid-Schiff (PAS) staining, and the expression of IDO1 and the macrophage surface marker F4/80 was determined in the vaginal tissues by an immunofluorescence method; real-time fluorescence-based quantitative PCR (qPCR) was performed to determine mRNA expression levels of IDO1, inducible nitric oxide synthase (iNOS), and arginase 1 (Arg-1) in the vaginal tissues, and Western blot analysis to determine the IDO1 protein expression in the vaginal tissues. One-way analysis of variance was used to analyze the differences in indices among groups, and Tukey test was used for multiple comparisons. Results:Smear microscopic examination of the vaginal lavage fluid on the 5th day of modeling showed elongated hyphae with a few spores in the VVC model group, a large number of elongated hyphae aggregating in clusters with surrounding spores in the 1-MT group, and a few thin and short hyphae with a large number of spores in the IFN-γ group. Compared with the VVC model group (360.0 ± 15.9), the fungal colony counts in the vaginal lavage fluid significantly increased in the 1-MT group (523.7 ± 67.7, P = 0.002), but significantly decreased in the IFN-γ group (258.3 ± 27.57, P = 0.026). HE staining and PAS staining showed small abscess formation in the epidermis and predominant infiltration of neutrophils throughout the epidermal and dermal layers with a large number of spores and a few hyphae in the VVC model group; thickened epidermis and diffuse inflammatory infiltration predominated by neutrophils in the dermis were seen in the 1-MT group, with a large number of hyphae and spores aggregating into clusters, which were predominated by hyphae; in the IFN-γ group, spores aggregated in the epidermis without obvious hyphae, and a small amount of inflammatory cells predominated by neutrophils infiltrated the dermis. Immunofluorescence assay revealed that the relative fluorescence intensities of IDO1 and F4/80 were highest in the IFN-γ group and the 1-MT group, respectively. Western blot analysis revealed that the IDO1 protein expression in the VVC model group was significantly higher than that in the blank group ( P < 0.001) and the 1-MT group ( P < 0.05), but significantly lower than that in the IFN-γ group ( P < 0.05). qPCR showed that iNOS mRNA expression significantly increased in the VVC model group compared with the blank group ( P < 0.01), and increased in the IFN-γ group compared with the blank group, VVC model group and 1-MT group (all P < 0.001); Arg-1 mRNA expression significantly increased in the VVC model group compared with the blank group ( P < 0.001) and IFN-γ group ( P < 0.01), and increased in the 1-MT group compared with the blank group, VVC model group, and IFN-γ group (all P < 0.001) . Conclusion:In the VVC mouse models, upregulation of IDO1 may cause macrophage polarization toward the M1 phenotype, and inhibition of IDO1 may cause increased macrophage recruitment and exacerbate the inflammatory response.
