Short communication: Concentration of TGF-β1, IL-10 and IL-6 in boar seminal plasma and TGF-β1 level in different fractions of ejaculates

Levels of the cytokines transforming growth factor (TGF)-β1, interleukin (IL)-10 and IL-6 in the boar seminal plasma (SP) as well as TGF-β1 level in different fractions of ejaculate were studied. These cytokines was chosen because of their expected effect on tissue immune response, i.e. suppressive (TGF-β1 and IL-10) and pro-inflammatory (IL-6). Three whole ejaculates from five boars A-E, (n=15) were sampled weekly to evaluate the levels of seminal plasma TGF-β1, IL-10 and IL-6 as well as their fluctuations over time. The effect of different storage temperatures, -20°C or -80°C, on the level of seminal plasma TGF β1 was also tested (three boars, two fractions in one ejaculate). In addition, in 4 different fractions of ejaculates: the pre-sperm-rich (Pre-SRF), first 10 ml of sperm-rich (10SRF), the rest of the sperm-rich fraction (Rest-SRF) and the rest of the ejaculate (RE) fraction, were collected from three boars (A-C) on four different occasions for TGF-β1 evaluation. In the whole ejaculates (n=15), a wide range in the concentration of the cytokines TGF-β1 (20.4 - 766.5 pg/mL) and IL-10, (73.7 - 837.3 pg/mL), was found. For IL-6, the concentration was low (range 11.5 - 30.9 pg/ml) and only detected in four out of 15 collections (from two boars). The mean levels of TGF-β1 and IL-10 between individual boars varied but were not statistical different. The level of TGF-β1 in Pre-SRF, Rest-SRF and RE fractions was significantly lower in boar A than the other boars. A significantly higher concentration of TGF-β1 was found in the 10SRF than in the other fractions. Different storage temperatures (-20°C or -80°C) did not affect the seminal plasma TGF-β1 level after one year of storage. To conclude: Boar seminal plasma contained TGF- β1 and IL-10 but with high individual variation. IL-6 was low or undetectable. The TGF- β1 level was highest in the first 10 mL of the sperm-rich fraction of the ejaculate. Further studies are needed on the role of different levels of cytokine in boar semen on porcine female reproductive tissue, especially for TGF- β1.