Identification of beta-nerve growth factor in dromedary camel seminal plasma and its role in induction of ovulation in females

Abstract

The main objective of this study was to demonstrate the effect of seminal plasma ovulation inducing factor (OIF) on ovulation in female camels. Seminal plasma was fractionated using gel filtration chromatography, and two protein peaks were obtained and analysed by western blotting. The effect of the bioactive protein fraction (OIF/β-NGF) was tested by intramuscular injection (1 ml) in synchronized females with the following treatments: PBS (negative control group, n = 3); 20 µg Buserelin (GnRH analogue, positive control group; n = 3); and purified OIF with doses of 1 and 2 mg (n = 5, each treatment). Blood samples were collected every two days from day 0 until 14 days post-treatment, and the progesterone concentration was assessed. The obtained results showed that the OIF is highly present in the seminal plasma of dromedary camels as a protein with a molecular mass of approximately 14 kDa. It was detected as a beta-Nerve Growth Factor, named Cam-β-NGF. The effect of this molecule on ovulation was clearly demonstrated by the significant increase of the plasma progesterone concentration in the treated female groups (1 and 2 mg of Cam-β-NGF) as observed in Buserelin group. In summary, intramuscular injection of β-NGF isolated from dromedary camel seminal plasma induces ovulation in females with similar rate to Buserelin treatment.