ABSTRACT
BACKGROUND: Conventional cryopreservation methods induce chemical and mechanical damage to the sperm membranes. The cryoprotectant potential of phospholipids of vegetal origin as soybean lecithin has been investigated as a substitute for egg yolk in diluents used for the cryopreservation of human spermatozoa. Therefore, the objective of this study was comparing the efficacy of a synthetic cryoprotectant supplemented with L-α-phosphatidylcholine (PC) and L-acetyl-carnitine (ANTIOX-PC) and the standard egg-based TEST-yolk buffer (TYB) in preserving sperm motility and chromatin quality in cryopreserved semen samples. METHODS: Prospective experimental study in which semen samples from 63 men with normal sperm motility and 58 men with low sperm motility were included and analyzed both before and after cryopreservation using ANTIOX-PC or TYB freezing media. Sperm quality was evaluated by routine semen analysis and DNA fragmentation index using the Terminal deoxynucleotidyl transferase dUTP nick end labeling assay. RESULTS: Differences in the post-thaw progressive motility and DNA fragmentation index were not detected between TYB and ANTIOX-PC cryoprotectants in both normal and low sperm motility groups (P>0.05). However, ANTIOX-PC medium retained higher non-progressive motility and lower percentage of immotile sperm when compared to TYB medium, resulting in a greater total motile sperm count (P<0.05), regardless baseline values of motility characteristic of the normospermic or asthenozoospermic samples. CONCLUSIONS: ANTIOX-PC medium was effective to protect human sperm during a freeze-thaw cycle compared to the TYB medium. A clinically relevant advantage in better preserving kinetic parameters as higher total motility and lower immotile post-thawed sperm from ANTIOX-PC, in normal and low motility semen samples, demonstrated the positive impact of phospholipid and antioxidant treatment on sperm cryotolerance with high potential for egg yolk lipids replacement and biosafety.
ABSTRACT
OBJECTIVE: This study aimed to evaluate the clinical pregnancy rate of intrauterine insemination cycles in relation to patient age, cause of infertility, ovulation induction method, number of mature follicles and sperm with progressive motility. METHODS: This retrospective observational study included 237 intrauterine insemination cycles performed from 2011 to 2015 at the Assisted Reproduction Service of the Hospital das Clínicas of the Ribeirão Preto Medical School, University of São Paulo. Student's t-test was used to compare quantitative variables and the chi-square test was used to compare qualitative variables. RESULTS: Patient age was inversely and significantly correlated with pregnancy rates (p=0.001) (Pregnant women = 32.56±5.64 years, non-pregnant women = 36.64±5.03 years). Cause of infertility, ovulation induction method, number of mature follicles and sperm with progressive motility were not associated with pregnancy rates. The overall clinical pregnancy rate was 7.59%. In the subgroup of patients (n=102 cycles) considered ideal for intrauterine insemination (age ≤35 years, unexplained infertility, ovarian factor infertility or minimal endometriosis, and a partner with sperm count ≥2.5 × 106 retrieved on the day of insemination) the pregnancy rate was 12.74%. CONCLUSION: In the studied group, female patient age was the only variable significantly correlated with intrauterine insemination success rates.
