Local expression of cytokine messenger RNA in rat model of Escherichia coli epididymitis.
OBJECTIVE
In order to investigate whether cytokines play an important role in the regulation of host defense against bacterial epididymitis, we examined the local expression of cytokine mRNA in a rat model of Escherichia coli epididymitis.


METHODS
Escherichia coli was inoculated into the spermatic cord of the rats and provoked epididymitis. At 6, 12, 24, 48, and 72 hours postinfection (p.i.) epididymides were harvested. We examined interleukin-6 (IL-6) and other inflammatory cytokine mRNAs in epididymides by Northern blotting and reverse transcriptase polymerase chain reaction (RT-PCR). Histopathological findings and immunohistochemistry for IL-6 were also examined.


RESULTS
Infected epididymides expressed IL-6 mRNA maximally at 6 hours p.i. and then the signal decreased by Northern blotting. mRNA for IL-1 beta and TNF-alpha also increased within 6 hours by RT-PCR. Histopathological examination showed that no inflammatory cells were observed at 6 hours p.i. and that inflammatory changes were most prominent at 72 hours p.i. Epididymal epithelium expressed IL-6 locally in response to local bacterial infection by immunohistochemistry.


CONCLUSIONS
mRNA for IL-1 beta, IL-6, and TNF-alpha is expressed locally in response to bacterial infection before inflammatory cell infiltration. This rapid expression in the epithelial cells may be important in host defense to local genital infection.
D000818:Animals; D016207:Cytokines / Q000235:genetics*; D004823:Epididymitis / Q000382:microbiology* / Q000473:pathology; D004926:Escherichia coli; D005786:Gene Expression Regulation / Q000235:genetics*; D015850:Interleukin-6 / Q000235:genetics*; D008297:Male; D012333:RNA, Messenger; D051381:Rats; D017208:Rats, Wistar
D016207:Cytokines; D015850:Interleukin-6; D012333:RNA, Messenger