Temperature controlled centrifugation improves sperm retrieval.

Sperm retrieval techniques form an integral part of the assisted reproductive programme. The success of sperm separation is measured by the number of motile sperm retrieved from a given semen sample. The study aimed to evaluate the effect of temperature during sperm preparation events on the number and percentage motile sperm retrieved following a double wash swim-up procedure. Thirty semen samples were obtained from 10 normozoospermic donors. After collection samples were divided into two aliquots, one aliquot was placed in an incubator at 34 °C, while the second aliquot was left at room temperature (25 °C). Sperm motility assessments were recorded with a computer assisted sperm analyser. Motile sperm fractions were retrieved from the semen samples following a double wash swim-up technique. Two tubes were prepared for each experiment. Tubes were placed in two different centrifuges: (i) SpermFuge (Shivani Industries, India) with temperature centrifuge control (34 °C) and (ii) Sigma with no temperature control facilities. Both centrifuges were set at 484 g for 5 min. Following the second wash, sperm pellets were layered with culture medium, and sperm was allowed to swim up. Supernatants were removed and analysed for sperm concentration and motility values. Percentage motile sperm was transformed to ARCSIN values and results of the two centrifugation methods at 34 °C and room temperature were compared with Mann-Whitney test for independent samples. The mean sperm concentration retrieved at 34 °C was 43.8 ± 50 (SpermFuge) and 32.7 ± 21 (Sigma) (P < 0.05), compared to retrieved concentration at room temperature namely, 30.9 ± 33 (SpermFuge) and 30.6 ± 17 (Sigma) (P ≥ 0.05). The mean percentage motile sperm at 34 °C was 64.0 ± 19 (SpermFuge) and 44.2 ± 24 (Sigma) (P = 0.02), while at room temperature the percentage motile sperm was 54.7 ± 17 (SpermFuge) compared to 46.5 ± 14 (Sigma) (P ≥ 0.05). Centrifuge temperature and incubation temperature significantly influenced the percentage retrieved motile sperm. The use of temperature-controlled sperm preparation might have clinical value for men with poor sperm motility values.