Age-related changes in the bovine corpus luteum function and progesterone secretion

Area of Science:

• Reproductive Biology
• Aging Research
• Veterinary Science

Background:

• Maternal aging is linked to decreased fertility and lower progesterone (P4) levels.
• The corpus luteum (CL) is crucial for pregnancy maintenance through P4 secretion.
• Bovine models offer insights into age-associated fertility decline due to physiological similarities with women.

Purpose of the Study:

• To investigate age-dependent changes in the bovine corpus luteum (CL).
• To examine inflammatory responses in the CL of cows of different ages.
• To understand the impact of aging on progesterone production and luteal function.

Main Methods:

• In vivo study: Compared plasma P4 levels in young, middle-aged, and aged cows during the estrous cycle.
• In vitro study: Analyzed CL tissue from young and aged cows for P4 concentration, secretion, and gene expression (StAR, 3β-HSD).
• Assessed inflammation and senescence markers in CL tissues.

Main Results:

• Aged cows exhibited significantly lower plasma P4 concentrations compared to young cows.
• In vitro, aged CL tissues showed reduced P4 concentration, secretion, and expression of StAR and 3β-HSD, particularly in the early luteal phase.
• No significant differences were found in inflammation or senescence markers between young and aged CL tissues.

Conclusions:

• Progesterone production and secretion by the bovine CL decrease in older cows.
• Senescence, rather than increased inflammation, appears to be the primary factor affecting luteal function with age.
• The bovine model effectively demonstrates age-related decline in luteal function relevant to human fertility studies.