Characterization of EST Gene in the Bovine Corpus Luteum during the Estrous Cycle

Abstract

The objective of this study was to investigate the expression of bovine luteum expressed sequence tags (ESTs), vascular endothelial growth factor (VEGF), and tumor necrosis factor receptor 1 (TNFR1) and the presence of functional ESTs in the bovine corpus luteum (CL) during different stages of the estrus cycle. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed a difference in the expression of ESTs during the CL stage. Concentration of ESTs in the CL tissue increased significantly from the mid-luteal stage and decreased thereafter. RT-PCR analysis showed higher levels of the EST genes in the CL of the mid-luteal stage than in other stages, and the same level of expression of VEGF. Immunohistochemistry analysis of the tissue from CL formation to regression showed low cytosol and aggregation of the nucleus. And activity caspase 3 (apoptosis detector) was most strongly detected in the CL1 stage of bovine. During the estrous cycle, the cytosol was magnified and differentiation of the nucleus was clearly manifested. The ESTs affected the CL, and the relationship between VEGF and TNFR1 played a pivotal role for CL development and activation, dependent on the stage of CL. These results suggest local production of ESTs, the presence of functional ESTs in the bovine CL, and that ESTs play a role in regulating the function of cell death in bovine CL.

Expression of matrix metalloproteinases to induce the expression of genes associated with apoptosis during corpus luteum development in bovine

“…The samples were placed into an LN2 freezer box and were transported to the laboratory within 2 h. In short, for the determination of the CL phase, a microscope evaluation was taken into account, which evaluated the color, consistency, and uterus of the entire ovaries. Estrous cycle luteal stages were classified into five categories by macroscopic observation as follows: corpora hemorrhagic (CH2) (1–2 cm), CH3 (>2 cm), CL3 (2.1–2.8 cm), CL2 (2.3–2.5 cm), CL1 (>2 cm) (Lee et al, 2015) (Table 1). This study was carried out in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health.…”

Inflammation and angiogenesis in the corpus luteum

“…[19][20][21] There are a series of essential morphological and biochemical changes that are induced by the rapid increase in luteinizing hormone. 22 The basement membrane divides the CL into two layers: a thecal layer and granulosa cell layer. The follicular vessels are located in the thecal layer and invade into the granulosa cell layer following the breakdown of the basement membrane.…”

“…New vessels are developed from preexisting ones, which make the CL grow rapidly and endocrine function also develops rapidly . There are a series of essential morphological and biochemical changes that are induced by the rapid increase in luteinizing hormone . The basement membrane divides the CL into two layers: a thecal layer and granulosa cell layer.…”

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“…In short, for the determination of the CL phase, a microscope evaluation was taken into account, which evaluated the color, consistency and uterus of the entire ovaries. Estrous cycle luteal stages were classified into five categories by macroscopic observation as follows: corpora hemorrhagic (CH2) (1-2 cm), CH3 (> 2 cm), CL3(2.1-2.8cm), CL2 (2.3-2.5 cm), CL1 (> 2 cm) (Lee et al, 2015) (Table 1). This study was carried out in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health.…”