Levocarnitine Improves the Sperm Density and Viability in a Rat Model of Varicocele via Increasing the Expression of Cation Channel of Sperm 1

Background: Varicocele is one of the common causes of infertility. In this study, we investigated whether levocarnitine could improve sperm density and viability in a varicocele rat model and change the Cation Channel of Sperm 1 (CatSper1) expression. Methods: Sixty male rats were randomly divided into six groups (n = 10 in each group): Control group, varicocele group, varic-ocele + normal saline group, and varicocele + small-, middle-, and large-dose of levocarnitine groups. Varicocele experimental model was established by partial ligation of the left renal vein. Twelve weeks later, the animals in the varicocele + normal saline group were gavaged with normal saline (1 mL center dot kg-1 center dot d-1), while the animals in groups varicocele + small-, middle-, large-dose le-vocarnitine were respectively gavaged with levocarnitine of different concentrations (0.01, 0.02, 0.03 g center dot kg-1 center dot d-1) for consecutive 35 days. We measured the semen parameters by computer-assisted semen analysis (CASA) and CatSper1 in sperms by Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Results: We found that sperm density, percentage of sperm motility with grade a + b and sperm viability were remarkably higher in the varicocele + small-, middle-and large-dose levocarnitine groups compared to the varicocele + normal saline group (p < 0.01). CatSper1 expression in sperms was significantly increased in varicocele + middle-and large-dose levocarnitine, compared to the varicocele + normal saline group (p < 0.01). Conclusions: Middle-and large-dose levocarnitine could increase sperm density and viability by increasing CatSper1 expression. Levocarnitine might be beneficial to asthenozoospermia caused by varicocele.