Infection of porcine colon explants with “Brachyspira hampsonii” leads to increased epithelial necrosis and catarrhal exudate

Abstract

Mucohemorrhagic diarrhea in pigs caused by Brachyspira spp. has a global distribution, and an economic impact on affected farms due to poor performance of animals. Demonstrations that "Brachyspira hampsonii" is pathogenic have been achieved using in vivo animal models, but a critical knowledge gap exists regarding the pathogenic mechanisms employed by Brachyspira. Here, we used in vitro organ culture of porcine colon to investigate interactions between "B. hampsonii" and explants during the first 12 h of contact. Explants were either inoculated with "B. hampsonii" or sterile culture broth. Responses to infection were evaluated by optical microscopy and quantitative PCR. Significantly greater numbers of necrotic crypt cells and thicker catarrhal exudate were observed on infected explants compared to controls. Spirochaetes were observed in the mucus layer, in contact with necrotic exfoliated cells, in crypts and the lamina propria. Statistical differences were observed in mRNA levels between inoculated and control explants for IL-1α, TNF-α and ZO-1 using a Bayesian analysis, but not observed using the ΔΔCq method. These results provide a demonstration of a porcine colon explant model for investigating interactions of Brachyspira with its host and show that initial effects on the host are observed within the first 12 h of contact.

Pathogenic disease modulation of pig intestinal function and integrity

“…In the current study, feed intake was reduced 45% in PRRS+ pigs, a more severe reduction than what has been reported. This is likely due to the age of pig and/or virulence of PRRSV strain utilized [37]. We also reported herein that PRRS+ pigs had accompanying reductions in growth rates.…”

“…As other researchers have had similar problems detecting Brachyspira spp. by next generation sequencing [37,38], it appears this organism is generally poorly amplified by 16s universal primers. It also highlights that 16s rRNA universal primers are not truly "universal" and are likely failing to detect any number of bacterial communities depending on the primer sequences used.…”

A review on the evolution of methods for intestinal in vitro organ culture and its application in veterinary science

“…Thus, this is an additional valuable method for studying intestinal antimicrobial immune responses. [24]. The intestinal fragment striped from the serosal layer is attached with an agar block -the attachment matrix -which allows nutrients from the culture media around it to permeate and nourish the explant.…”

“…Polypropylene cylinders were attached to explants using tissue glue to polarize the stimulus (100 μL of inoculum containing Brachyspira hampsonii was added in this study). Subsequently, the plates were incubated in hyperoxic chambers containing 99% O 2 and 1% CO 2 for 8 h ( Figure-3 ) [ 24 ].…”

Bovine mammary epithelial cells can grow and express milk protein synthesis genes at reduced fetal bovine serum concentration

“…Bayesian MCMC (Markov chain Monte Carlo) sampling scheme that if desired, can incorporate reference gene data into the model as priors (Costa et al, 2017). Using this package after soft-normalization, the efficiency corrected Ct values are transformed into molecular counts.…”