Action of nitric oxide on vascularization of bitches with pyometra submitted to drug treatment

Abstract

Pyometra is a condition of the female reproductive system consisting of the accumulation of purulent secretion in the uterine lumen. The etiology is not yet fully elucidated but is influenced by steroid hormones (progesterone and estrogen). In canine pyometra, high blood flow in the uterine artery and high endometrial vascularization is related to increased expression of VEGF and its receptors in the endometrium, inducing the activity of the enzyme endothelial nitric oxide synthase (e-NOS) and, consequently, an increase of the basal level of nitric oxide (NO). Aglepristone is a competitive progesterone antagonist drug of high affinity for the receptors of this hormone, being used for the drug treatment for canine pyometra. There is little data in the scientific literature that measures and correlates serum NO levels and e-NOS expression in the uterus before and after drug treatment with aglepristone in bitches with pyometra. Therefore, the objective of this study is to evaluate the influence of drug treatment with aglepristone on the expression of the enzyme nitric oxide synthase in the uterus and to measure serum levels of nitric oxide. Thus, this study will use 20 bitches diagnosed with a pyometra, being allocated in 2 groups: control (submitted to ovariohysterectomy) and aglepristone (submitted to the drug therapy with aglepristone and later to ovariohysterectomy). Both groups will be evaluated by B-mode, color flow Doppler and pulsed-wave Doppler ultrasonography. Uterine fragments will be randomly collected for analysis of the immunohistochemical expression of the endothelial nitric oxide synthase enzyme and blood samples for indirect measurement of nitric oxide by the reduction of nitrites and nitrates.