Significance of nitric oxide concentration in plasma and uterine secretes with puerperal endometritis in dairy cows.

Endometritis is an inflammation of the endometrial lining of the uterus without systemic signs, which is associated with chronic postpartum infection of the uterus with pathogenic bacteria. Nitric oxide (NO) is an inflammatory mediator that among other effects causes smooth muscle relaxation and mediated cytoimmunity and inflammation toxicity. To see if the nitric oxide concentration in plasma and uterine secrets is related with postpartum endometritis, NO concentrations in plasma and uterine secrets were measured in dairy cows with puerperal endometritis (clinical endometritis (n = 60) and subclinical endometritis (n = 58)). Cows with clinical or subclinical endometritis showed higher concentrations of NO in both plasma and uterine secrets when compared with normal cows and the highest concentrations of NO in plasma and uterine secrets were found in dairy cows with clinical endometritis. Expression level of NOS2 mRNA in endometrial biopsies from cows with puerperal endometritis was also higher and the highest expression of NOS2 mRNA was found in cows with clinical endometritis. The results showed that concentrations of NO in plasma and uterine fluid are related with the degree of endometritis which may be useful to diagnose the endometritis in dairy cows.