Protective effect of L-carnitine on sperm motility and membrane integrity in men asthenoteratozoospermia: An in vitro study

Sperm preparation is a time-consuming process that makes a contribution to oxidative stress induction in assisted reproductive techniques.

This study aimed to evaluate the effect of L-carnitine on sperm parameters during semen preparation at different time intervals.

In this in vitro study, the semen samples of 50 asthenoteratozoospermic men were divided into the control and the L-carnitine groups (incubated with 0.5 mg/mL L-carnitine) (n=25/each). Total motility, progressive motility, sperm membrane integrity (by Hypo-osmotic swelling test), and lipid peroxidation (by Malondialdehyde level) were assessed in each group after 2, 4, and 6 hours. Afterward, samples were analyzed by the World Health Organization (2010) criteria.

The results showed that in the control group total and progressive motility, and membrane integrity of the sperm were significantly decreased after 2 hr (P= 0.028, p= 0.019, and p= 0.025, respectively), while Malondialdehyde levels increased significantly after 4 hr (P= 0.018). Sperm parameters in the L-carnitine group increased significantly after 2 hr (P= 0.002), while Malondialdehyde levels decreased significantly compared to the control group in 6 hr (P < 0.001 vs. P =0.045).

Based on these results, L-carnitine can manage to conserve motility and sperm membrane integrity of sperm from the hazardous impact of oxidative stress and lipid peroxidation during sperm preparation.