Coded slides were identified correctly as estrus or proestrus by two observers on the basis of quantity and distribution of luteal MCP-1 staining. In addition to staining in the corpora lutea, immunodetectable MCP-1 was seen in many follicles and vascular spaces throughout the ovary. This is not surprising, as MCP-1 is a secreted protein made by a number of cell types present in the ovary, including macrophages, epithelial cells, and fibroblasts. We have previously observed that MCP-1 is prevalent in atretic follicles, which also contain macrophages (unpublished results). buy birth control online
Apoptotic nuclei were detected by in situ hybridization in sections of ovaries from rats killed on the morning of proestrus (n = 6), the morning of estrus (n = 5), and the afternoon of estrus (n = 5). Mean ± SEM numbers of apoptotic nuclei per high-power field were, respectively, 1.6 ± 0.2, 5.3 ± 1.3, and 4.5 ± 0.8 (p < 0.05, proestrus vs. morning of estrus; p < 0.05, proestrus vs. afternoon of estrus; Fig. 3). Cross sections of all corpora lutea, excluding the newly formed corpora lutea on estrus, were used in this analysis, without regard to age of the corpora lutea. Atretic follicles within the same sections exhibited striking numbers of apoptotic nuclei. Frequently, all granulosa cells visible in a follicular section would stain positively for DNA fragmentation (data not shown).
FIG. 3. Numbers of apoptotic cells per high-power field within corpora lutea of multiple ages (whole ovarian sections) from rats killed on pro-estrus, estrus AM, and estrus PM (experiment 1). Different letters indicate significant differences at p < 0.05.