Hemodynamic changes detected by Doppler ultrasonography in the ovaries of cattle during early development of cystic ovarian disease.

A common reproductive disease in dairy cattle is Cystic Ovarian Disease. To study its development, there was use of an experimental model of follicular persistence to detect hemodynamic changes occurring in ovaries by using Doppler ultrasonography. After estrous synchronization, control cows received no additional treatment and were evaluated at proestrus (CG), whereas treated cows (PG) received sub-luteal doses of progesterone for 15 days and were evaluated at proestrus, and after 0, 5, 10 and 15 days of follicular persistence. Spectral Doppler was used to evaluate blood flow in the ovarian artery, and power Doppler for evaluation of blood flow in the ovarian parenchyma and follicular wall of persistent and dominant preovulatory follicles. Findings using power Doppler signals indicated there were no differences between groups in the parenchyma of both right (P =  0.455) and left (P =  0.762) ovaries. In contrast, power Doppler signals of blood flow were less in walls of persistent follicles from day 0 to 15 when there was follicular persistence than in dominant follicles of the CG (P <  0.001). Blood flow in ovarian arteries was less (P <  0.05) in diastolic velocity and time averaged maximum velocity in all PG groups than in the CG. Peak systolic velocity was less (P <  0.05) in all PG than in the CG, with the exception of P15 (P >  0.05). These findings indicate there are marked changes in blood irrigation area of walls of persistent follicles during the 15 days of follicular persistence.

Altered expression of cytokines IL-1α, IL-6, IL-8 and TNF-α in bovine follicular persistence.

In dairy cattle, cystic ovarian disease (COD) is an important cause of subfertility, and two of the main signs are ovulation failure and follicular persistence. The aim of this study was to examine the expression of the cytokines IL-1α, IL-6, IL-8 and TNF-α in ovarian follicular structures at different times of persistence in a model of follicular persistence induced by prolonged treatment with progesterone in dairy cows. Protein expression of IL-1α, IL-6, IL-8 and TNF-α was evaluated by immunohistochemistry. Additionally, IL-6 concentration in follicular fluid and serum was determined by ELISA. IL-1α, IL-6, IL-8 and TNF-α expression was increased in follicles with different persistence times in relation to the control dominant follicles, in granulosa cells. For IL-6, IL-8 and TNF-α, this increase was detected early (P0: expected time of ovulation and/or P5: 5 days of follicular persistence). Additionally, theca cells showed an increase in IL-6 in antral (groups P10 and P15) and persistent follicles (group P10) related to dominant follicles from the control group (p < 0.05). Serum concentration of IL-6 was higher in groups P5, P10 and P15 than in control cows (p < 0.05). The results show evidence that early development of COD in cows is concurrent with altered expression of these cytokines in different ovarian follicular structures and may contribute to the follicular persistence and endocrine changes found in cattle with follicular cysts.