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°C; 5% CO2 in air) at a concentration of 20 × 106/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 μM; a threshold of greater than or equal to 130 μM/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.
- Cyclic adenosine monophosphate
- Primate sperm
ASJC Scopus subject areas