The Effect Of Elevated Cortisol Levels On Goats With Acute Endometritis Induced By Uterine Infusion With E. Coli

Endometritis is a postpartum disease usually caused by pathogenic microorganisms which predominantly affects dairy animals.This disease leads to decrease in dairy output,increased fertilization failure and major economic losses.Cortisol is a primary homeostatic regulator during the inflammatory response to injury.During parturition,cortisol levels are elevated in the maternal bloodstream.In this paper,we observed the role of cortisol in the regulation of the response to acute endometritis in the goat model.Twelve healthy goats were randomly divided into three groups:control group,E.coli group and the cortisol treatment group.Daily intravenous cortisol infusion of 1mg/kg was administered to the cortisol treatment group 3 days before uterine infusion of E.coli and continued throughout the experiment.The E.coli group received daily intravenous saline and uterine infusion of E.coli.The control group received intravenous saline infusion and uterine infusion of PBS.White blood cell count,temperature,pulse and respiration were observed at pre-inoculation(0h),12,24,96 and 168h post inoculation.Serum cortisol levels were measured.Uterine discharge was collected for cytological examination under a microscope and bacterial culture.Histopathology of the endometrial tissues were observed using H&E stain.The relative gene expression changes of TLR4,IL-β,IL-6,1L-8,TNF-α,TGF-β and VEGF in endometrial tissue was detected using quantitative real time PCR.WBC count was significantly elevated(p<0.05)in the E.coli and cortisol treatment group compared to the control group at 12h after inoculation.This elevation returned to pre-inoculation levels 24h after infection.There was a discernible elevation in serum cortisol levels of the cortisol treatment group compared to the control and E.coli group throughout the experiment,Increased rectal temperature was noted in the E.coli and cortisol treatment group at 12h post infection.Respiration rose sharply in the cortisol treatment group at 24h but returned to normal by 96h.There was no significant difference in heart rate between the various groups.A large amount of PMNs were visible in uterine discharge in the E.coli and cortisol treatment group at 24h after infection.Positive bacterial cultures were obtained from the E.coli and cortisol treatment group at 12 and 24h after infection.Significant leukocyte infiltration of the uterine tissue was observed in the E.coli group and cortisol treatment group at 24h,followed by a gradual reduction.No significant variances in mRNA expression of TLR4,IL-1β and TNF-α were observed after 24h,however,IL-6 and IL-8 mRNA was significantly lower in the cortisol treatment group at 24 and 96h after infection(p<0.05).TGF-β mRNA expression was similar in all groups before and after infection.VEGF mRNA expression was significantly lower in the cortisol treatment group compared to the E.coli group at 24h post infection(p<0.01).