Gaytán F, Bellido C, Morales C, Sánchez-Criado J E
Department of Cell Biology, Faculty of Medicine, University of Córdoba, 14004 Córdoba, Spain.
Biol Reprod. 2001 Aug;65(2):433-41. doi: 10.1095/biolreprod65.2.433.
We studied the morphological and quantitative changes in cyclic corpora lutea (CCL) and in CL of pregnancy (CLP) during structural luteolysis. Elimination of CCL takes several cycles, and cell death occurs as successive apoptotic bursts, from 2100 h in proestrus to 1300 h in estrus. Each apoptotic burst determined a 60% decrease in the CL volume and an 80% decrease in the number of steroidogenic cells (SC). All these changes were inhibited by blocking the preovulatory prolactin (PRL) surge with bromocryptine (CB154). Neither apoptotic cells nor changes in the number of SC were found in regressing CLP from Day 21 of pregnancy to Day 2 postpartum, although there was a 50% decrease in the CLP volume and a 30% decrease in the mean cross-sectional area of SC. Treatment with CB154 on the day of parturition did not modify these regressive changes. On Day 5 postpartum, the volume of the CLP and the number of SC were equivalent in lactating rats (showing high PRL concentrations induced by pup suckling) and nonlactating noncycling rats (in which cyclicity and, therefore PRL surges, were blocked by treatment with LHRH antagonist). However, on Day 10 postpartum, the CLP volume and the number of SC were significantly decreased in lactating rats, and apoptotic cells were frequent. In postpartum cycling rats, the CLP did not show apoptotic cells on the day of the second postpartum estrus (on Day 5 postpartum), whereas on the day of the third postpartum estrus (on Day 9 postpartum), apoptotic cells were abundant. These results indicate that PRL does not induce apoptosis in the CLP before Day 5 postpartum and strongly suggest that the proapoptotic effect of PRL is dependent on the degree of differentiation of luteal cells.
我们研究了在结构性黄体溶解过程中，周期性黄体（CCL）和妊娠黄体（CLP）的形态学和定量变化。CCL的消除需要几个周期，细胞死亡以连续的凋亡爆发形式发生，从发情前期的21:00到发情期的13:00。每次凋亡爆发导致黄体体积减少60%，类固醇生成细胞（SC）数量减少80%。所有这些变化都通过用溴隐亭（CB154）阻断排卵前催乳素（PRL）激增而受到抑制。从妊娠第21天到产后第2天，退化的CLP中既未发现凋亡细胞，SC数量也未发生变化，尽管CLP体积减少了50%，SC平均横截面积减少了30%。分娩当天用CB154处理并未改变这些退化变化。产后第5天，哺乳大鼠（显示由幼崽吸吮诱导的高PRL浓度）和非哺乳非周期性大鼠（其周期性以及因此的PRL激增通过用促性腺激素释放激素拮抗剂处理而被阻断）的CLP体积和SC数量相当。然而，产后第10天，哺乳大鼠的CLP体积和SC数量显著减少，且凋亡细胞频繁出现。在产后周期性发情的大鼠中，产后第二次发情当天（产后第5天）CLP未显示凋亡细胞，而在产后第三次发情当天（产后第9天），凋亡细胞大量存在。这些结果表明，产后第5天之前PRL不会诱导CLP凋亡，并强烈提示PRL的促凋亡作用取决于黄体细胞的分化程度。
