Effects of L-carnitine and pentoxifylline on long-term preservation of the human sperms: An experimental study

In infertility clinics, long-time preserving high-quality spermatozoa is a challenging problem.

The present study aimed to prolong preserving of the human spermatozoa by adding pentoxifylline (PT) and L-carnitine (LC) without using high-cost freezing techniques.

In this experimental study, semen samples of 26 normozoospermia men aged between 28-34 yr, were firstly prepared using the swim-up technique, and each sample was divided into the following 3 aliquots: untreated control group, the LC, and PT-treated groups. The samples were stored for up to 12 days at 4-6 C, and sperm motility was assessed. The percentages of the sperms with double-stranded DNA, apoptotic, and acrosomal interacted sperms were evaluated by sperm chromatin structure assay, AnnexinV-PI staining, and peanut agglutinin, respectively.

On day 7, 26.83% $\pm$ 4.26 of sperms were motile in the PT group which was significantly more than LC (6.67% $\pm$ 0.61) and control (0.83 $\pm$ 0.17) groups (p $<$ 0.001). At day 12, while all sperms lost their motility in LC and control groups, adding PT led to 3.17% $\pm$ 0.47 sperms remaining motile (p $<$ 0.001). Moreover, on day 12, the percent of apoptotic sperms in the PT-treated group (8% $\pm$ 0.20) was significantly lower than in LC-treated group (5.9% $\pm$ 0.28, p = 0.03). None of the additives positively affected the number of sperms with double-stranded DNA (p $>$ 0.05). LC could also maintain acrosomal integrity over a storage time of up to 12 days.

Despite PT's improved sperm motility, LC was more efficient in preventing apoptosis and acrosomal reactions. However, DNA was resistant to denaturation regardless of the treatments.