The Role Of NADPH Oxidase P47phox Subunit In The Process Of Chlamdydia Muridarum Infection And Pathogenesis In Mice

Chlamydia trachomatis is an obligate intracellular parasite and a major cause of human blindness and sexual transmitted disease. C. trachomatis infection can lead to endometritis, cervicitis and salpingitis in women, resulting in complications such as ectopic pregnancy and tubal factor infertility. The mechanisms by which C.trachomatis organisms induce inflammatory pathologies in genital tract remain unknown. And no effective vaccine has been licensed until now. There is less genital tract inflammation in mice inoculated with C. trachomatis. And murine biovar C. muridarum can cause inflammatory pathologies that are similar to those in humans. Therefore C. muridarum genital tract infection in mice has been used extensively as a model for investigating the mechanisms of C. trachomatis pathogenesis and immunity.In this research, we investigated the role of NADPH(nicotinamide adenine dinucleotide phosphate)- oxidase in the process of C. muridarum infection and pathogenesis. NCF1(neutrophil cytosolic factor 1)- encoded p47phox(phagocyte oxidase) is an essential subunit of NADPH oxidase. Deficiency of p47 phox can severely compromise the function of NADPH oxidase. To study the role of NADPH oxidase in infection and pathogenesis of C. muridarum in mouse,p47 phox deficient mice and wild type mice were inoculated intravaginally with C.muridarum. Vaginal swabs were taken on different days after infection to monitor C. muridarum infection in the lower genital tracts. Mice were sacrificed in the late stage of infection and the mouse urogenital tract tissue were isolated for in situ gross examination of uterine horn dilation and hydrosalpinx. Urogenital tract tissue sections were made for microscopic evaluating of pathology and counting of different types of inflammatory cells. To study whether NADPH oxidase plays a role in prevention of chlamydial ascending infection, p47 phox deficient mice and wild type mice were sacrificed in early stage of infection. Genital tract tissue ofeach mouse was cut into segments. Each segment sample was homogenized for titration of chlamydia organisms.In this paper, we found that both p47 phox deficient and sufficient mice displayed similar low genital tract shedding following an intravaginal infection.There is no significant difference in uterine horn dilation between these two groups of mice, however deficient mice developed limited hydrosalpinx compared with sufficient mice. Less mononuclear cells were found in the oviduct of deficient mice under microscope. In the early stage of infection, both groups of mice displayed similar mount of chlamydia organisms in upper genital tract. These results demonstrate that NADPH oxidase plays an important role in C. muridarum induced inflammation response and pathology in oviduct but not in uterine horn tissue. NADPH oxidase is not required for the mouse control of chlamydial infection in low genital tract and ascension from lower to upper genital tract. This research can provide fundamental understanding for chlamydia pathogenesis in human.Apart from the above mentioned studies, histopathologic basis of C.muridarum-induced uterine horn dilation was also investigated in this paper.Dilated glandular ducts in mouse endometrium that pushed the uterine horn lumen to closure or dilation may contribute to dilated uterine horn. The severity scores of uterine horn dilation correlates well with the number of dilated glandular ducts counted under microscopy. C. muridarum organisms ascended to upper genital tract following intravaginal inoculation and indeed infected the glandular duct epithelial cells. These results indicate the dilated endometrial glandular ducts maybe lead to the uterine horn dilation following intravaginal inoculation of C.muridarum.