Evaluation of cannabinoid receptors Type 1 and Type 2 mRNA expression in mature versus immature spermatozoa from fertile and infertile males.

The expression of the main cannabinoid receptors (CBR1 and CBR2) was investigated to evaluate the possible association with the sperm maturation from fertile and infertile individuals. One hundred subjects were classified into fertile (n = 50) and infertile groups (n = 50). Fresh semen samples were collected. Computer-assisted semen analysis and acrosin activity test were done. RNA was extracted from mature and immature sperm pellets. Reverse transcriptase reaction and real-time PCR were done to assess the levels of both CBR1 and CBR2 genes expression in all samples. Mature spermatozoa from both groups showed significantly higher levels of both CBR1 and CBR2 compared with the immature spermatozoa (p < .05). This increment was significantly more important in the fertile group (p < .05). In mature spermatozoa, CBR1 expression was significantly related to variation in sperm morphology, and CBR2 was significantly related to both sperm morphology and linearity index. In conclusion, CBR1 and CBR2 mRNA expression may closely direct the sperm maturation at different steps of the reproductive process.