Effects Of Lcn5 On Sperm Capacitation And Motility In Goats

Retinoic acid-binding protein (Lcn5) was one of transport lipoproteins family. Previous studies in our group have showed that Lcn5 was higher expressed in testis and epididymis of buck. Lcn5 was located at goat acrosomal cap and middle piece of tail. It is suggested that Lcn5 could play an important role in sperm maturation and capacitation. The aim of this study was to investigate the effect of Lcn5 on sperm capacitation and motility in goat.The optimal concentration and effects on sperm capacitation of anti-Lcn5 antibody were determined with motility of sperm examined by Integrated Semen Analysis System (ISAS) and with the capacitation rate of sperm stained by chlortetracycline (CTC) after sperms were treated by 10?g/mL,50?g/mL and 100 ?g/mL anti-Lcn5 antibody. Sperm treated with optimal concentration of anti-Lcn5 antibody, were detected in movement parameters, motility and percentage of sperm capacitation every 10 min in 1 h to select the optimal time of sperm capacitation and analyze the effects on motility after being treated by anti-Lcn5 antibody. Cervical mucus from adult does in estrus was collected to evaluate penetration ability of sperm treated by the optimal concentration and time of anti-Lcn5 antibody. The results showed as follows:1. Lcn5 was located at acrosomal cap and middle piece of tail of ejaculated sperm before capacitation. After being treated by heparin, there was no positive signal in capacitated sperm induced by heparin, whereas it was still in middle piece of tail of capacitated sperm.2. Sperms were treated by 10?g/mL anti-Lcn5 antibody had higher capacitation rate and the percentage of rapid motility than that in the 50?g/mL and 100?g/mL groups (P<0.05), there was no significant difference on medium movement sperms in groups being treated by 10?g/mL and 100?g/mL anti-Lcn5 antibody (P>0.05), while medium movement sperms were significantly increased compared with 50?g/mL anti-Lcn5 antibody group (P<0.05). There was no significant difference on capacitation rate in groups being treated by 10?g/mL anti-Lcn5 antibody for 30 min and 40 min (P>0.05), while capacitation rate was significantly increased compared with the other groups (P<0.05). There was significant difference on medium movement sperms in groups being treated for 30 min compared with the other groups (P<0.05). Sperms treated by 10?g/mL anti-Lcn5 antibody for 30 min had a higher capacitation rate and motility than that in the other concentration treatment groups and the control group (P <0.05), and significantly higher movement parameters in the linear velocity (VSL), the average velocity (VAP), the linearity index (LIN), the oscillation index (WOB), the frequency of tail sperm beat (BCF) and the straightness index (STR) of the sperms (P<0.05). There was no significant difference in groups treated by 10?g/mL anti-Lcn5 antibody for 30 min and 40 min (P>0.05). There was no significant difference in the curvilinear velocity (VCL) between the treatment of 40 min and 30 min (P>0.05). which was significantly higher than that in other time treatment groups. From 10 min to 60 min, the trend of VSL, VAP, LIN, WOB, BCF and STR of the sperms were first rise then after decline.3. Cervical mucus penetration trail showed that sperm penetration ability was significantly increased after being treated by anti-Lcn5 antibody compared with control group (P<0.01), while it had no significant difference between anti-Lcn5 antibody and heparin treatment groups (P> 0.05).Conclusion:Lcn5 was located at acrosome cap region and middle piece of tail of uncapacitated sperm, Lcn5 had no significant changes at middle piece of tail with Lcn5 disappearing after sperm capacitation. Sperm capacitation and acrosomal reaction could be induced by anti-Lcn5 antibody, endogenous Lcn5 had great effects on integrity of sperm acrosomal and sperm capacitation. Sperm motility and sperm penetration in the cervical mucus were significantly increased after being treated by anti-Lcn5 antibody.