The effects of cryopreservation on sperm morphology, motility and mitochondrial function

TLDR

The study evaluated cryoinjury on human sperm by measuring mitochondrial activity with Rhodamine 123 uptake and intensity, morphology via Tygerberg's strict criteria, viability with eosin Y, and motility using computer‑assisted semen analysis on samples from 50 men. Cryopreservation reduced normal sperm morphology by 37 %, lowered all CASA motility parameters (except amplitude of lateral head displacement), decreased Rhodamine 123 uptake by 36 % and intensity by 47 %, and lowered viability by 31 %, indicating that morphology, motility, mitochondrial function and viability are equally vulnerable to cryoinjury, with R123 intensity emerging as a robust indicator.

Abstract

The effects of cryoinjury were determined simultaneously on the mitochondrial function, motility, morphology and viability of ejaculated human sperm.Rhodamine 123 (R123) uptake (% of sperm) and stain intensity were used to determine sperm mitochondrial activity before and after cryopreservation from the semen of 50 men attending for infertility investigation. Morphology was assessed using Tygerberg's strict criteria and viability was assessed by eosin Y. Sperm motility was measured using computer-assisted semen analysis (CASA).Freeze-thawing caused a 37% (P = 0.001) reduction in normal morphological forms of sperm. All CASA sperm motility parameters except amplitude of lateral head displacement were similarly reduced. R123 uptake and intensity within sperm mitochondria decreased by 36 and 47% respectively (both P = 0.001). In addition, there was a similar significant decrease (31%, P = 0.001) in the viability of the sperm.Sperm morphology, motility, mitochondrial activities and viability are equally susceptible to cryopreservation-induced damage. R123 intensity is a novel and robust indicator of mitochondrial function before and after such trauma.