Efeitos do tratamento com progestágenos sobre o útero de gatas domésticas

Abstract

Brazil has the second largest pet population in the world, and domestic cats have grown to a greater extent. In addition to this growth, the number of abandoned animals has also increased, as well as low rates of adoption. The creation of these animals without accompaniment by the veterinarian, unrestricted mobility and lack of reproductive control will damage their well-being and may result in human suffering, such as disease transmission and environmental contamination, forming a problematic framework for public health. All this problem of excessive procreation and its consequences has also increased the use of contraceptives, which have numerous undesirable effects, so it is necessary to know the reproductive anatomy of the domestic cat (Felis catus), as well as to know the protocols of contraception more specific and efficient, in view of the mechanisms of action and indication, which bring less collateral damage, and safer methods to reproductive control. The literature review aimed to address the reproductive anatomy of domestic cat (Felis catus) and the most used contraceptive methods, mechanism of action, dosages used, advantages and disadvantages of each protocol considered. In this sense, the evaluation and the search for less costly contraceptive methods is an alternative to birth control, taking into account the relationships that the drugs have and their side effects. The objective of the experiment was to evaluate the effects of progesterone-based contraceptives in domestic cats, uterine macroscopy, immunosuppressive effect in endometrial cytology and histopathology. Seventeen unprotected cats were used up to two years of age, with no history of reproductive pathologies or prior application of contraceptives. These animals were divided in three experimental groups, control group (n = 7) without administration of progestins, oral group (n = 4) application of oral progestogen and injectable group (n = 6) application of injectable progestogen. After 12 weeks, the animals were submitted to ovariohysterectomy for analysis. Uterine macroscopic alterations were similar in the oral and injectable groups, where a large part had a thickened uterine wall, a hypertrophied endometrium with folds. The cytological effects demonstrated a decrease in the leukocyte response in the oral and injectable groups. In the morphological and histological analyzes, the results showed more dilated endometrial glands in the oral group, followed by the injectable group, accompanied by the decrease of the lamina propria. The other structures analyzed, total myometrium, internal circular, vascular and external longitudinal strata had higher mean values than the control group, which demonstrated the effects of P4 in these uterine structures, which confirms the influence of the organ structure. The effects of progestins on the uterus of cats treated with megestrol acetate and medroxyprogesterone, where the main alterations were in height of superficial epithelium, total myometrium, internal circular muscle, vascular stratus and external longitudinal muscle.