Caspases, a family of cysteine protease enzymes, are a critical component of apoptotic cell death, but they are also involved in cellular differentiation. The expression of caspases during apoptotic processes in reproductive tissues has been shown in some species; however, the expression and regulation of caspases in the endometrium and placental tissues of pigs has not been fully understood. Therefore, we determined the expression of caspases CASP3, CASP6, CASP7, CASP8, CASP9, and CASP10 in the endometrium throughout the estrous cycle and pregnancy. During the estrous cycle, the expression of all caspases and during pregnancy, the expression of CASP3, CASP6, and CASP7 in the endometrium changed in a stage-specific manner. Conceptus and chorioallantoic tissues also expressed caspases during pregnancy. CASP3, cleaved-CASP3, and CASP7 proteins were localized to endometrial cells, with increased levels in luminal and glandular epithelial cells during early pregnancy, whereas apoptotic cells in the endometrium were limited to some scattered stromal cells with increased numbers on Day 15 of pregnancy. In endometrial explant cultures, the expression of some caspases was affected by steroid hormones (estradiol-17β and/or progesterone), and the cytokines interleukin-1β and interferon-γ induced the expression of CASP3 and CASP7, respectively. These results indicate that caspases are dynamically expressed in the endometrium throughout the estrous cycle and at the maternal-conceptus interface during pregnancy in response to steroid hormones and conceptus signals. Thus, caspase action could be important in regulating endometrial and placental function and epithelial cell function during the implantation period in pigs.

半胱氨酸蛋白酶家族中的半胱天冬酶是凋亡细胞死亡的重要组成部分，但它们也参与细胞分化。在某些物种的细胞凋亡过程中，胱天蛋白酶的表达已经显示。然而，胱天蛋白酶在猪的子宫内膜和胎盘组织中的表达和调控尚未得到完全了解。因此，我们确定了胱天蛋白酶的表达CASP3，CASP6，CASP7，CASP8，CASP9， 和 10号在整个发情周期和怀孕期的子宫内膜中。在发情周期中，所有胱天蛋白酶的表达以及在怀孕期间，CASP3，CASP6， 和 CASP7子宫内膜的改变以特定阶段的方式改变。孕期概念和绒膜尿囊组织也表达胱天蛋白酶。CASP3，裂解的CASP3和CASP7蛋白定位于子宫内膜细胞，在怀孕早期的管腔和腺上皮细胞中水平升高，而子宫内膜的凋亡细胞仅限于一些分散的基质细胞，在妊娠第15天数量增加。在子宫内膜外植体培养物中，某些胱天蛋白酶的表达受类固醇激素（雌二醇-17β和/或孕酮）的影响，而细胞因子白介素1β和干扰素-γ诱导其表达。CASP3 和 CASP7， 分别。这些结果表明，胱天蛋白酶在整个发情周期的子宫内膜中动态表达，并且在妊娠期间响应类固醇激素和概念信号在母体-概念界面中动态表达。因此，胱天蛋白酶的作用可能在调节猪植入期间子宫内膜和胎盘的功能以及上皮细胞的功能中起重要作用。