P–103 Novel sperm preparation techniques compared with conventional preparation method

Study question

Which sperm preparation technique separate the best quality sperm?

Summary answer

Microfluidic method improved the sperm parameters and decreased sperm DNA damage.

What is known already

About 40% of infertility issues are due to male factor. One of the known causes of male infertility is associated with low sperm parameters and high level DNA fragmentation. Sperm preparation techniques in ICSI procedures is used in order to obtain the best-quality sperm.

Study design, size, duration

The present study was designed to compare Microfluidic, Zeta potential, Magnetic Activated Cell Sorting (MACS) and Swim-up methods for sperm preparation and the effect of these methods on semen parameters and sperm DNA integrity in infertile men (n = 25) with a mean age of 38.

Participants/materials, setting, methods

In this study, each sample was divided into 4 groups, one part for preparing by Microfluidic method, one of them for preparing by Swim -up method, the other one was prepared by MACS and the last one was prepared by zeta potential. Then sperm count, viability, motility and morphology were assessed according to WHO 2010. DNA damage were assessed by Sperm DNA Fragmentation assay and sperm chromatin packaging assessed by CMA3 staining test

Main results and the role of chance

Sperm parameters including viability, motility, and morphology in the Microfluidic method were significantly improved and sperm DNA damage were significantly lower than three other methods (P-value <0.05). The sperm parameters and sperm DNA damage after preparation by MACS and Zeta potential methods were not significantly different however in the Swim-up method sperm parameters were lower than three other methods (P-value <0.05).

Limitations, reasons for caution

The fertilization and pregnancy rate of the resulting embryos are not available.

Wider implications of the findings: Our results showed that Microfluidic can be an effective way to improve sperm quality of infertile male compared to conventional preparation methods. We also found instead of the MACS method, we can use the Zeta potential method according to their costs, for sperm preparation during ART cycle.

Trial registration number

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Direct measurement of the accumulation and mitochondrial conversion of nitric oxide within Chinese hamster ovary cells using an intracellular electron paramagnetic resonance technique

We have developed an electron paramagnetic resonance (EPR) method for the nondestructive detection and quantification of intracellular NO in real time. Based upon this technique, we have obtained evidence for the metabolism of this bioregulatory molecule by mitochondria. Line-broadening of the EPR signal of a coal derivative, fusinite, was calibrated as a function of NO concentration in aqueous solution. The methodology was validated using two compounds which release NO in a controlled and predictable manner with first-order rate constants k1 = 5.0 x 0.10(-3) s-1 and k'1 = 3.4 x 10(-4) s-1 (35 degrees C). Fusinite was internalized in Chinese hamster ovary cells (CHO) by phagocytosis, after which the cells were allowed to consume the available O2, producing an hypoxic environment. The NO released from one of the NO donors, added to the culture fluid at an initial concentration of 50 microM, was directly measured in the intracellular environment as line-broadening of the fusinite EPR signal. The linewidth diminished with time, indicating that NO was being converted to a non-paramagnetic species by the cells with an apparent zero-order rate constant of 5 x 10(8) NO molecules cell-1 min-1 (20 degrees C). Addition of cyanide to the culture medium (5 mM final concentration) inhibited this disappearance of NO. NO also was converted in the presence of isolated mitochondria in the absence of oxygen. These observations suggest that under hypoxic conditions, there exists in CHO cells a metabolic pathway for the conversion of NO to diamagnetic species, which involves interactions with mitochondria.

In vivo and in vitro EPR oximetry with fusinite: a new coal-derived, particulate EPR probe

The peak-to-peak line width (LW) of the first derivative electron spin resonance (EPR) spectrum of the coal maceral fusinite is reversibly broadened by O2. The extent of broadening per unit of partial pressure of oxygen (pO2) is unusually large, exceeding that of nitroxides by almost two orders of magnitude. This paramagnetic property of fusinite, combined with its very stable physicochemical properties and low toxicity, is shown to be of utility in the measurement of pO2 in vitro and in vivo. Fusinite particles are endocytosed by chinese hamster ovary (CHO) cells in vitro; this is useful for intracellular O2 measurements with commercially available EPR spectrometers operating at 9.1-9.3 GHz. For measurement of oxygen in vivo using low frequency EPR (1.1-1.3 GHz), fusinite provides a sensitive and persistent means to measure pO2 in tissues. Particles implanted into the gastrocnemius muscle of A/J mice remained interstitially in the same position for months with undiminished sensitivity to pO2 and no specific toxic effects.

Lithium phthalocyanine: a probe for electron paramagnetic resonance oximetry in viable biological systems

Lithium phthalocyanine (LiPc) is a prototype of another generation of synthetic, metallic-organic, paramagnetic crystallites that appear very useful for in vitro and in vivo electron paramagnetic resonance oximetry. The peak-to-peak line width of the electron paramagnetic resonance spectrum of LiPc is a linear function of the partial pressure of oxygen (pO2); this linear relation is independent of the medium surrounding the LiPc. It has an extremely exchange-narrowed spectrum (peak-to-peak line width = 14 mG in the absence of O2). Physicochemically LiPc is very stable; its response to pO2 does not change with conditions and environments (e.g., pH, temperature, redox conditions) likely to occur in viable biological systems. These characteristics provide the sensitivity, accuracy, and range to measure physiologically and pathologically pertinent O2 tensions (0.1-50 mmHg; 1 mmHg = 133 Pa). The application of LiPc in biological systems is demonstrated in measurements of pO2 in vivo in the heart, brain, and kidney of rats.

Measurements of pertinent concentrations of oxygen in vivo

A new method able to measure the concentration of oxygen in complex biological systems, including in vivo, has been developed using low-frequency EPR and newly characterized free radicals that are very sensitive to the concentration of oxygen. The free radicals (fusinite and lithium phthalocyanine) are very stable in tissues (for at least 150 days), apparently nontoxic, and can reflect oxygen concentrations that are less than the Km of cytochrome oxidase (0.1 microM or lower). Their biological stability is indicated by the fact that repeated measurements with fusinite of the concentration of oxygen in skeletal muscle have been made in the same animal for more than 150 days without any change in sensitivity or signs of toxicity.