Investigating the Suitability of a Laboratory Mouse Model to Study the Pathogenesis of Abortifacient Campylobacter jejuni

The mechanism of action of safflower total flavonoids in the treatment of endometritis caused by incomplete abortion based on network pharmacology and 16S rDNA sequencing

ETHNOPHARMACOLOGICAL RELEVANCE

Safflower is a traditional Chinese medicine used for treating gynaecological diseases. However, its material basis and mechanism of action in the treatment of endometritis induced by incomplete abortion are still unclear.

AIM OF THE STUDY

This study aimed to reveal the material basis and mechanism of action of safflower in the treatment of endometritis induced by incomplete abortion through comprehensive methods, including network pharmacology and 16S rDNA sequencing.

MATERIALS AND METHODS

Network pharmacology and molecular docking methods were used to screen the main active components and potential mechanisms of action of safflower in the treatment of endometritis induced by incomplete abortion in rats. A rat model of endometrial inflammation by incomplete abortion was established. The rats were treated with safflower total flavonoids (STF) based on forecasting results, serum levels of inflammatory cytokines were analysed, and immunohistochemistry, Western blots, and 16S rDNA sequencing were performed to investigate the effects of the active ingredient and the treatment mechanism.

RESULTS

The network pharmacology prediction results showed 20 active components with 260 targets in safflower, 1007 targets related to endometritis caused by incomplete abortion, and 114 drug-disease intersecting targets, including TNF, IL6, TP53, AKT1, JUN, VEGFA, CASP3 and other core targets, PI3K/AKT, MAPK and other signalling pathways may be closely related to incomplete abortion leading to endometritis. The animal experiment results showed that STF could significantly repair uterine damage and reduce the amount of bleeding. Compared with the model group, STF significantly down-regulated the levels of pro-inflammatory factors (IL-6, IL-1β, NO, TNF-α) and the expression of JNK, ASK1, Bax, caspase3, and caspase11 proteins. At the same time, the levels of anti-inflammatory factors (TGF-β and PGE2) and the protein expression of ERα, PI3K, AKT, and Bcl2 were up-regulated. Significant differences in the intestinal flora were seen between the normal group and the model group, and the intestinal flora of the rats was closer to the normal group after the administration of STF.

CONCLUSIONS

The characteristics of STF used in the treatment of endometritis induced by incomplete abortion were multi-targeted and involved multiple pathways. The mechanism may be related to the activation of the ERα/PI3K/AKT signalling pathway by regulating the composition and ratio of the gut microbiota.

Campylobacter jejuni persistently colonizes gnotobiotic altered Schaedler flora C3H/HeN mice and induces mild colitis

Campylobacter jejuni is a major cause of food-borne human bacterial gastroenteritis but animal models for C. jejuni mediated disease remain limited because C. jejuni poorly colonizes immunocompetent, conventionally-reared (Conv-R) mice. Thus, a reliable rodent model (i.e. persistent colonization) is desirable in order to evaluate C. jejuni-mediated gastrointestinal disease and mechanisms of pathogenicity. As the nature and complexity of the microbiota likely impacts colonization resistance for C. jejuni, Conv-R and gnotobiotic C3H/HeN mice were used to evaluate the persistence of C. jejuni colonization and development of disease. A total of four C. jejuni isolates readily and persistently colonized ASF mice and induced mild mucosal inflammation in the proximal colon, but C. jejuni did not stably colonize nor induce lesions in Conv-R mice. This suggests that the pathogenesis of C. jejuni is influenced by the microbiota, and that ASF mice offer a reproducible model to study the influence of the microbiota on the ability of C. jejuni to colonize the gut and to mediate gastroenteritis.