Effects of environmental tobacco smoke in vitro on rhesus monkey sperm function.

The objective of this study was to use a non-human primate model to examine the effect of ETS on sperm function. Sperm samples were collected from adult rhesus monkeys (Macaca mulatta) and treated with different levels of ETS exposed medium. ETS treatment decreased the percentage of motile sperm and motion parameters. Sperm treated with ETS exposed medium showed a limited response to the activators and exhibited decreased binding to the zonae pellucida after activation. The mitochondrial integrity of the ETS-treated sperm was disrupted; however, there was no decrease in viability compared to control groups. Sperm acrosomal status was similar in the control and treatment groups. The results imply that the exposure of primate sperm to ETS could impair sperm transport in vivo.

Changes in membrane lipid order with capacitation in rhesus macaque (Macaca mulatta) spermatozoa.

Lipophilic fluorescent dye merocyanine 540 is believed to stain cell membranes with increasing affinity as the lipid components become more disordered and has been associated with changes in membrane fluidity. The aim of this study was to determine whether membrane lipid disorder is associated with capacitation of macaque spermatozoa. To induce capacitation, spermatozoa from 5 rhesus macaques were incubated at 37 degrees C (5% CO(2) in air) for 2 hours in a modified Biggers-Whitten-Whittingham medium containing 30 mg/mL bovine serum albumin and 36 mmol/L NaHCO(3). Caffeine (1 mmol/L) and dbcAMP (1.2 mmol/L) were added to the medium, and incubation was performed for an additional 30 minutes. Sperm motility was determined by computer-assisted sperm analysis, and membrane lipid order and sperm viability was determined by flow cytometry with merocyanine (2.7 micromol/L) and Yo-Pro-1 (25 nmol/L), respectively. Tyrosine phosphorylation of proteins in sperm tail was immunohistochemically examined by means of anti-phosphotyrosine (alpha-PY; clone 4G10). Capacitation resulted in a significant increase in the amplitude of lateral head displacement and beat cross frequency (P < .005) and a significant decrease in linearity and straightness in capacitated spermatozoa (P < .005), compared with control spermatozoa, which suggests the expression of hyperactivated motility. Animals in which capacitation was induced had a significant increase in the number of spermatozoa showing tyrosine phosphorylation of tail proteins (P < .0001) and a significant increase in the intensity of merocyanine fluorescence (P < .0001), compared with control animals. The observed decrease in membrane lipid order after capacitation was induced was not associated with surface exposure of phosphatidylserine, as determined by flow cytometry with annexin V-Alexa Fluor 488. Merocyanine may be a useful tool for investigating the role of the plasma membrane on capacitation and other cytotoxic events in macaque spermatozoa.

Hyperactivated motility in rhesus macaque (Macaca mulatta) spermatozoa.

Macaque spermatozoa can be capacitated according to a defined protocol and exhibit hyperactivated motility similar to that described in other species. The aim of this study was to create a method for defining hyperactivation that could be routinely used in the laboratory alongside our existing sperm motility analysis protocol. Percoll-separated macaque spermatozoa were incubated for 2 hours (37 degrees C; 5% CO(2) in air) at a concentration of 20 x 10(6)/mL in bicarbonate (36 mmol)-buffered Biggers, Whitten and Whittingham medium (BWW) containing 30 mg/mL bovine serum albumin (BSA), followed by an additional 30 minutes with (capacitated) or without (incubated) caffeine (1 mmol) and dibutyryladenosine 3',5'-cyclic monophosphate (dbcAMP; 1.2 mmol). One hundred and fifty progressive and hyperactivated tracks were selected from each of three monkeys. Thresholds for hyperactivation were based on the 10th (amplitude of lateral head displacement, ALH) and 90th (linearity, LIN) percentiles of the hyperactivated kinematic data set and were LIN less than or equal to 69% and ALH greater than or equal to 7.5 microM; a threshold of greater than or equal to 130 microM/s was also included for curvilinear velocity (VCL). These thresholds were 91% effective at identifying hyperactivated tracks. Capacitation of macaque spermatozoa, by the addition of caffeine and dbcAMP, resulted in a significant increase in ALH, VCL, and beat cross frequency and a significant decrease in total and progressive motility, straight line velocity, straightness, and LIN when compared to incubated spermatozoa, suggesting the expression of hyperactivated motility. Utilizing the above thresholds, hyperactivation was expressed by 5% +/- 0.8% of the incubated sperm population vs 53 +/- 3.7% of the capacitated sperm population (P < .0001). Hyperactivation was not observed when dbcAMP and caffeine were added separately and was significantly (P < .005) reduced by the addition of H-89. The results of this paper demonstrate that hyperactivation can be reliably estimated for rhesus macaque spermatozoa.

Reactive oxygen species and cryopreservation promote DNA fragmentation in equine spermatozoa.

The objective of this study was to examine the effect of reactive oxygen species (ROS) and cryopreservation on DNA fragmentation of equine spermatozoa. In experiment 1, equine spermatozoa were incubated (1 hour, 38 degrees C) according to the following treatments: 1) sperm alone; 2) sperm + xanthine (X, 0.3 mM)-xanthine oxidase (XO, 0.025 U/mL); 3) sperm + X (0.6 mM)-XO (0.05 U/mL); and 4) sperm + X (1 mM)-XO (0.1 U/mL). In experiment 2, spermatozoa were incubated (1 hour, 38 degrees C) with X (1 mM)-XO (0.1 U/mL) and either catalase (200 U/mL), superoxide dismutase (SOD, 200 U/mL), or reduced glutathione (GSH, 10 mM). Following incubation, DNA fragmentation was determined by the single cell gel electrophoresis (comet) assay. In experiment 3, equine spermatozoa were cryopreserved, and DNA fragmentation was determined in fresh, processed, and postthaw sperm samples. In experiment 1, incubation of equine spermatozoa in the presence of ROS, generated by the X-XO system, increased DNA fragmentation (P <.005). In Experiment 2, the increase in DNA fragmentation associated with X-XO treatment was counteracted by the addition of catalase and GSH but not by SOD, suggesting that hydrogen peroxide and not superoxide appears to be the ROS responsible for such damage. In experiment 3, cryopreservation of equine spermatozoa was associated with an increase (P <.01) in DNA fragmentation when compared with fresh or processed samples. This study indicates that ROS and cryopreservation promote DNA fragmentation in equine spermatozoa; the involvement of ROS in cryopreservation-induced DNA damage remains to be determined.