Effect of cycle stage on immunoglobulin concentrations in reproductive tract secretions of the mare.

This research examines the relationship between the stage of a horse’s reproductive cycle and the presence of immunoglobulin and albumin levels in serum, follicular fluid, and secretions from the oviduct, uterus, and vagina. The study shows that these levels vary during the reproductive cycle, affecting the horse’s immune response.

Study Overview

• The researchers studied variations in immunoglobulin (antibodies) and albumin (a type of protein) levels in various elements during a mare’s reproductive cycle. These elements included serum (the clear, yellowish part of blood), follicular fluid (liquid surrounding a developing egg in the ovary), and secretions from the reproductive system.

Key Findings

• The levels of immunoglobulins in the blood did not change during the mare’s oestrous cycle (periodically recurring physiological changes). However, the levels of IgM (a type of immunoglobulin), were found to be higher in cyclic mares (those undergoing normal reproductive cycles) than in non-cyclic (those not in their reproductive cycle).
• The researchers observed no cyclical variation in protein concentrations in the follicular or oviductal sectors.
• In the uterus, the IgG and IgA (types of immunoglobulins) levels relative to total protein were higher during the oestrogenic stage than in the progestagenic stage of the cycle. Conversely, IgM concentrations had a reverse trend.
• For mares sampled repeatedly during a single oestrous cycle, protein levels in their secretions were affected by the method used for collection. But, the researchers found variation in the total protein, as well as IgG, IgA, and albumin levels, with the highest levels during dioestrus and the lowest at oestrus.
• Protein concentrations were found to be higher in vaginal secretions than uterine ones, despite a higher relative concentration of IgA to total protein in the uterus compared to the vagina.

Implications

• The findings suggest immunoglobulin and albumin concentrations in various parts of the reproductive system are affected by the phase of a mare’s oestrous cycle. This variation could influence the mare’s immune response during its reproductive cycle, possibly affecting fertility or susceptibility to infections.