Metalloproteinase distribution in the intercellular matrix of chorioallantoic villi and caruncular crypts in cows with placental insufficiency

Fifteen placental samples measuring 1.0 x 1.0 cm² were analyzed, obtained from each of 10 Holstein cows, whose age ranged from 3 to 5 years, with a weight in the range of 650 to 750 kg and a milk yield of 13,000 to 15,000 liters per lactation. Placental samples were divided into two categories: from 5 cows with physiological pregnancy (PP) and from 5 cows with complicated pregnancy, suffering from placental insufficiency (PI). The diagnosis of PN was based on laboratory blood and urine tests, as well as morphological examination of the fetal membranes after delivery. It was found that in the placenta of cows with PN in late pregnancy, structural changes are observed in the caruncle tissues, leading to degradation of the connective matrix of the crypts, which is associated with the lack of order in the interstitial substance. Translocation of matrix metalloproteinases MMP-1 and MMP-3 was observed in the space between the epithelium of the villi of the allantochorion of the cotyledon and the epithelial cells of the crypts of the caruncles. MMP-2 and MMP-9 were located in the cytoplasm of syncytiotrophoblast cells. The structural features of the placenta in PN are expressed in the formation of an allantochorionic organization with a disruption of the structure of the cotyledon villi. Moreover, if in FB MMP-9 with TIMP-1 and MMP-2 with TIMP-2 can be considered as membrane proteins, then in the case of PN they are usually localized in the cytoplasm. This indicates a low expression of collagen in the central part of the placenta and its instability. Collagen type III is unevenly distributed in the placenta from cows with PN, especially in the paracentral and marginal zones, where its expression is completely absent.