Local Expression Dynamics of Various Adipokines during Induced Luteal Regression (Luteolysis) in the Bovine Corpus Luteum

SIMPLE SUMMARY: Within the intricacies of the reproductive cycle, the regression of the corpus luteum (CL) plays a pivotal role. This temporary endocrine structure, formed post-ovulation, undergoes regression in the absence of pregnancy. The CL experiences rapid and profound changes in function and structure. This process, known as luteal regression or luteolysis, remains a cornerstone of the female reproductive system’s mechanics. Notably, within ovarian physiology, a domain of local regulation has been unveiled. Thus, our investigation set out to explore the enigmatic realm of locally produced adipokines and their receptor dynamics within the CL during experimentally induced luteolysis. Through meticulous examination at diverse stages of CL regression, we unveiled significant fluctuations in adipokine expression, unveiling their potential roles in orchestrating corpus luteum lysis or the resumption of cyclicity. ABSTRACT: The study aimed to evaluate the mRNA expression levels of various local novel adipokines, including vaspin, adiponectin, visfatin, and resistin, along with their associated receptors, heat shock 70 protein 5, adiponectin receptor 1, and adiponectin receptor 2, in the corpus luteum (CL) during luteal regression, also known as luteolysis, in dairy cows. We selected Fleckvieh cows in the mid-luteal phase (days 8–12, control group) and administered cloprostenol (PGF analog) to experimentally induce luteolysis. We collected CL samples at different time points following PGF application: before treatment (days 8–12, control group) and at 0.5, 2, 4, 12, 24, 48, and 64 h post-treatment (n = 5) per group. The mRNA expression was measured via real-time reverse transcription polymerase chain reaction (RT-qPCR). Vaspin was characterized by high mRNA levels at the beginning of the regression stage, followed by a significant decrease 48 h and 64 h after PGF treatment. Adiponectin mRNA levels were elevated 48 h after PGF. Resistin showed upregulation 4 h post PGF application. In summary, the alterations observed in the adipokine family within experimentally induced regressing CL tissue potentially play an integral role in the local regulatory processes governing the sequence of events culminating in functional luteolysis and subsequent structural changes in the bovine ovary.