P-074 In-vitro vitamin D treatment on human sperm improves sperm motility, capacitation, and oocyte activation
Authors: Ang W Y , Hamdan M , Nelli G 
Published: June 2023

Abstract

Study question
Does in-vitro vitamin D treatment on fertile and infertile human sperm improves sperm motility and alter protein markers involved in capacitation and oocyte-activation.

Summary answer
In-vitro vitamin D treatment enhance functionality of sperm by increase intracellular calcium ion, thus increasing sperm motility and capacitation status.

What is known already
Many studies have been done to investigate the relationship between vitamin D and male infertility. It is known that low serum vitamin D in human contribute to male infertility. However, the effect of in-vitro vitamin D treatment on sperm remains unclear, particularly on the effect of vitamin D following ejaculation into female reproductive tract. This includes processes involved in fertilisation such as capacitation, hyperpolarization, oocyte activation and sperm-oocyte fusion. Therefore, we examined whether in-vitro vitamin D treatment on sperm can improve the sperm parameters, hence will then improve fertilisation and pregnancy.

Study design, size, duration
Randomised controlled trial with prospective interventions (in-vitro vitamin D treatment). Based on power analysis, 40 subjects both fertile and infertile men who came for semen analysis were recruited at University Malaya Medical Centre from January 2022 to January 2023. All men were consented to participate in this study. Each washed semen sample were aliquoted to serve as control and receive in-vitro vitamin D treatment.

Participants/materials, setting, methods
Total of 40 samples were included for final analysis. All semen samples were washed and treated with 1nM vitamin D in-vitro for 45 minutes at 37ºC. Motility, intracellular calcium released, capacitation status, mitochondria membrane potential and other basic semen parameters were measured after in-vitro vitamin D treatment for fertile and infertile samples. Furthermore, immunofluorescence of sperm origin oocyte activation factor, Phospholipase C Zeta (PLCζ), was done to investigate fluorescence intensity per cell using Image J.

Main results and the role of chance
In both fertile and infertile sample group, total motility is increased after in-vitro vitamin D treatment (MD = 8.727%, P &lt; 0.001). Fluo-4 AM stain shows there are increase of intracellular calcium release after in-vitro vitamin D, with mean difference of Corrected Total Cell Fluorescent (CTCF) for Fluo-4 AM (MD = 25043, P = 0.0228. Chlortetracyclin (CTC) test for capacitation status and immunofluorescence of phosphotyrosine shows there are increase CTCF (MD = 0.02595, P = 0.0142) after in-vitro vitamin D treatment. Staining of JC-1 shows there are more hyperpolarised mitochondria membrane in in-vitro vitamin D treatment group compare to the control group. Ratio of red to green fluorescent is 0.639 in control group and 2.22 in in-vitro vitamin D treatment group. Moreover, immunofluorescence of sperm origin oocyte activation factor, Phospholipase C Zeta (PLCζ) show in-vitro vitamin D improve the expression of these protein. Mean difference of CTCF between control and vitamin D treatment group for PLCζ is 8.013x 10-3, P = 0.0226. Thus, in-vitro vitamin D enhance functionality of sperm by increase intracellular calcium ion, thus increasing sperm capacitation status and sperm membrane hyperpolarization.

Limitations, reasons for caution
Although power analysis is used to calculate sample size, however bigger sample size always needed to increase the accuracy. Moreover, patients’ sample are examined and treated after 3 hours due to limited collection room in the facility.

Wider implications of the findings
Vitamin D can be used as a tool in in-vitro fertilisation (IVF) procedure and can be added to sperm preparation medium due to its implication in increasing capacitation and hyperpolarised sperm membrane to increase chance of successful IVF.

Trial registration number
not applicable