Relationship between Clusterin Gene Expression and In-vitro Sperm Characteristics in Caprine Semen

Abstract

The present experiment was undertaken to study the relationship between clusterin (CLU) gene expression and in vitro sperm characteristics in buck semen. Fresh semen samples were collected from 12 bucks maintained in the organized goat farms by artificial vagina. Normalization of initial concentration of spermatozoa was carried out in all buck semen samples before proceeding for RNA isolation. So, initial concentration of each sample was made equal. The spermatozoa were isolated from buck semen samples by swim-up protocol using sperm TALP. Total RNA from the buck spermatozoa were extracted and first strand cDNA was synthesized from 1μg total RNA by using commercial kits. Absolute quantification of CLU gene transcripts in semen samples from 12 bulls was performed by plotting standard curve. Variations in levels of CLU gene transcripts (2500-22546000 copies) were found among 12 different buck semen samples. In vitro sperm characteristics were also studied from 12 buck semen samples. Variations in sperm characteristics such as sperm motility (60.0-80.0%), sperm viability (72.0-93.0%), sperm morphology (73.0-91.0%), plasma membrane integrity (50.0-82.0%), acrosome integrity (81.0-93.0%), DNA integrity (82.0-93.0%) and MMP (46.0-74.0%) were found among buck semen samples. All in vitro sperm characteristics were highly (negatively) correlated (p<0.01) with expression levels of CLU gene transcripts in spermatozoa. From this study, it is evident that ejaculated buck semen has variations in transcription pattern of CLU gene in spermatozoa among bucks and expression levels of CLU transcripts have negative correlation with in vitro sperm characteristics in buck semen samples.