Morphometric changes on the endometrium during diestrus stages in bitches with and without histological endometritis

Abstract The endometrium is a uterine layer essential for achieving optimal embryo implantation and development. Complete knowledge of the endometrium's normal histology is critical for advancing the diagnosis of subclinical endometrial diseases. Several researchers studied subclinical endometritis (END) in different species; however, the cause is unknown, and simple and reliable diagnostic tools are still necessary. In the bitch, diestrus has been selected as the stage of the reproductive cycle to perform diagnostic. This work aimed to perform morphometric and cytological studies in bitches with normal endometrium (NE) and END in the diestrus' different stages. Forty-five mixed-breed bitches, clinically healthy in diestrus, were used in this study. Biopsies and cytology were obtained from uterine horns, processed, and examined using a microscope. Samples from NE and END were selected, photographs were taken, and software for image analysis was used to measure the endometrial thickness (ET), external glandular diameter (EGD), and internal glandular diameter (IGD), glandular density, and glandular cells (GC) height. Significant differences were observed in GC height, EGD, IGD, and serum P 4 concentrations along diestrus. In END, EGD and IGD were smaller than NE. The current study showed histomorphometric characteristics that appear to be influenced by P 4 concentrations. In our opinion, it is relevant to consider the diestrus stage at the moment of the diagnosis of endometrial disease. Data recorded in the present study could be helpful to bitches with unexplained infertility or subfertility.