IGF2 and IGF1R mRNAs Are Detectable in Human Spermatozoa

Area of Science:

• Reproductive biology
• Molecular genetics
• Spermatozoa function

Background:

• Oligozoospermia, characterized by low sperm count, is a global health concern.
• Previous research indicated altered methylation in the H19 differentially methylated region in oligozoospermic patients.
• The roles of IGF2 and IGF1R transcripts in human sperm remain largely unexplored.

Purpose of the Study:

• To determine the presence of IGF2 and IGF1R messenger RNAs (mRNAs) in human spermatozoa.
• To investigate the correlation between the levels of IGF2 and IGF1R mRNAs and conventional sperm parameters, specifically sperm concentration and total sperm count.

Main Methods:

• Sperm samples from 22 individuals were analyzed using reverse-transcription quantitative polymerase chain reaction (RT-qPCR).
• Specific primers were employed to detect and quantify IGF2 and IGF1R mRNA levels.
• Spearman and Kendall rank correlation coefficients were used to assess associations with sperm parameters.

Main Results:

• Significant positive correlations were observed between IGF2 mRNA levels and both sperm concentration (τ=0.403, p<0.01; ρ=0.587, p<0.005) and total sperm count (τ=0.347, p<0.024; ρ=0.509, p<0.015).
• IGF1R mRNA levels showed strong positive correlations with sperm concentration (τ=0.595, p<0.001; ρ=0.774, p<0.001) and total sperm count (τ=0.547, p<0.001; ρ=0.701, p<0.001).
• A positive correlation was also found between IGF1R mRNA and sperm morphology (τ=0.325, p<0.05; ρ=0.461, p<0.05).

Conclusions:

• IGF2 and IGF1R mRNAs are demonstrably present in human spermatozoa.
• The transcription levels of IGF2 and IGF1R mRNAs are positively associated with sperm concentration and total sperm count.
• Given that IGF2 is paternally imprinted, spermatozoa represent the sole source of IGF2 mRNA, warranting further investigation into its role in human fertilization.