Objective

Myo-inositol is a naturally occurring component of vitamin B complex that is involved in cellular signaling pathways. There is a growing evidence on the potential beneficial effects of Myo-inositol supplementation on both natural and assisted fertility. The objective of this study was to investigate the effects of in vitro Myo-inositol supplementation of cryopreserved human semen on the post-thaw sperm quality.

Design

A randomized controlled trial (RCT).

Materials and Methods

The study had been approved by the institutional review board, and conducted in an infertility center between September 2016 and March 2017. The study included semen samples obtained from 25 infertile men during routine infertility work-up. Myo-inositol was supplied in a powder form (Sigma Aldrich Chemical Co, USA). Under complete aseptic condition, Myo-inositol was dissolved in sperm nourishment media (AllGrad wash®, Life global, Canada) to prepare aliquots of 10 μl stock solutions, each containing 1 mg Myo-inositol. Standard semen analysis was performed according to the WHO guidelines (fifth edition, 2010). Azoospermic and leukocytospermic samples were excluded. Each semen sample was divided into two equal aliquots (0.5 ml each) for cryopreservation using slow freezing technique. The two identical aliquots of each semen sample were randomized into two groups (A and B). Group A was treated with cryo-protectant plus 10 μl Myo-inositol solution, while group B was treated with cryo-protectant alone (control). Frozen samples were thawed at 37 °C, and examined for post-thaw total motility, progressive motility and progressive recovery rate (PRR). PRR = post-thaw progressive motility/pre-freeze progressive motility X100. Data were presented as median (25th and 75th percentiles). Paired sample t test was used for comparison of the pre and post-thaw results. P value < 0.05 was considered significant.

Results

The median (25th, 75th) of pre-freeze sperm concentration was 25 (18, 41) X106 sperm, and percentage of normal sperm forms was 4 (2, 5). Comparisons of pre-freeze and post-thaw percentages of total motility, progressive motility and PRR between samples in group A and group B are shown in Table 1.

Conclusions

In vitro Myo-inositol supplementation of cryopreserved ejaculate sperm, from infertile men, resulted in a significant enhancement of post-thaw sperm quality. Such finding is interesting, and may have important implications on the future outcome of assisted reproductive techniques using cryopreserved sperm.

 
Comparisons of pre-freeze and post-thaw percentages of total motility, progressive motility and PRR
Parameter Pre-freeze Group A Group B P 1 (pre-freeze vs Group A) P 2 (pre-freeze vs Group B) P 3 (Group A vs Group B)
Total Motility (%) 40 (31, 45) 10 (4.5, 15) 10 (3.8, 10) < 0.001 < 0.001 0.03
Progressive Motility (%) 25 (16, 25) 5 (1.5, 10) 5 (1.8, 5) 0.04 0.001 0.01
Progressive Recovery Rate (%)   12.5 (6.4, 25.0) 10 (4.3, 18.8)