Automated sperm morphology analysis (ASMA) technology has improved the assessment of sperm morphology, but the results depend on the use of adequate and standardized procedures. In this study the Sperm-Class Analyzer (SCA) ASMA system was used to assess sperm head morphometry in the Cynomolgus monkey and to evaluate the influence of sample size, intraslide variation, and the use of three staining techniques on the accuracy of image processing and sperm head morphometry. Haematoxylin is the staining technique of choice for Cynomolgus spermatozoa, as optimum contrast of sperm heads with the surrounding background allows efficient segmentation, i.e. sperm head boundary detection, making the image analysis process more accurate. The analysis of 100 spermatozoa is recommended since a larger sample size did not result in more accurate sperm head morphometry. There were no differences in either the percentage of correctly binarized sperm heads or sperm head dimensions among samples obtained from different zones of the slides, although differences in stain intensity (grey level) were detected. The measurements made on Haematoxylin, Diff-Quik and Hemacolor-stained slides yielded different values for all of the sperm head parameters under consideration. This result demonstrates that the procedures of fixation and staining significantly affect the dimensions of sperm heads.

The aim of this study was to give reference values for the frequency of morphological sperm abnormalities present in the semen from nonexperimental cynomolgus monkeys as well as for the dimensions of sperm heads. Spermatozoa from the liquid portion of electroejaculates from 14 cynomolgus monkeys were air‐dried as smears, fixed, and stained with Harris's Haematoxylin and subjected to visual analysis of morphology and computer‐aided analysis of ten morphometric variables. The majority (83%) of sperm were morphologically normal. Tail defects were the most common (11%), and showed the highest variation between individuals, the values ranging between 4 and 23%. Head abnormalities consisted of large, tapering, and amorphous forms but were not frequent (0.4%), the values ranging between 0 and 1.3%. Midpiece imperfections were found in all the individuals; the mean percentage was 5%, and the range varied between 3 and 9%. Tail plus midpiece was the only multiple abnormality observed, with a mean value of 1.5% and a range between 0 and 8%. The majority of these double defects consisted of a coiled tail together with a coiled midpiece. Mean values for the morphometric parameters characterizing sperm heads were as follows: area 17.2 μm2, perimeter 15.2 μm, length 5.8 μm, width 4.0 μm, L/W ratio 1.5, gray‐level 98, ellipticity 0.2, first shape factor 0.9, second shape factor 1.4, and third shape factor 1.1. Overall coefficients of variation for the majority of parameters were below 7%, showing the great homogeneity in the dimensions of cynomolgus sperm heads. Most useful parameters for sperm characterization, according to their low variability, were perimeter, length, width, L/W ratio, and shape factors. Differences in these parameters were, however, observed between monkeys. Am. J. Primatol. 47:105–115, 1999. © 1999 Wiley‐Liss, Inc.

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The aim of this study was to give reference values for the frequency of morphological sperm abnormalities present in the semen from non-experimental cynomolgus monkeys as well as for the dimensions of sperm heads. Spermatozoa from the liquid portion of electroejaculates from 14 cynomolgus monkeys were air-dried as smears, fixed, and stained with Harris's Haematoxylin and subjected to visual analysis of morphology and computer-aided analysis of ten morphometric variables. The majority (83%) of sperm were morphologically normal. Tail defects were the most common (11%), and showed the highest variation between individuals, the values ranging between 4 and 23%. Head abnormalities consisted of large, tapering, and amorphous forms but were not frequent (0.4%), the values ranging between 0 and 1.3%. Midpiece imperfections were found in all the individuals; the mean percentage was 5%, and the range varied between 3 and 9%. Tail plus midpiece was the only multiple abnormality observed, with a mean value of 1.5% and a range between 0 and 8%. The majority of these double defects consisted of a coiled tail together with a coiled midpiece. Mean values for the morphometric parameters characterizing sperm heads were as follows: area 17.2 microm2, perimeter 15.2 microm, length 5.8 microm, width 4.0 microm, L/W ratio 1.5, gray-level 98, ellipticity 0.2, first shape factor 0.9, second shape factor 1.4, and third shape factor 1.1. Overall coefficients of variation for the majority of parameters were below 7%, showing the great homogeneity in the dimensions of cynomolgus sperm heads. Most useful parameters for sperm characterization, according to their low variability, were perimeter, length, width, L/W ratio, and shape factors. Differences in these parameters were, however, observed between monkeys.

The importance of the cynomolgus monkey as a model for human reproductive medicine prompted this examination of epididymal sperm morphology. Computer‐aided sperm morphological analysis was used for the first time to provide morphometric data on sperm heads as they traversed the epididymal duct of Macaca fascicularis. The duct was divided into six regions, starting close to the testis (proximal) and ending close to the vas deferens (distal). To determine the androgen‐dependence of the changes, one group of animals received a GnRH‐antagonist (Cetrorelix, Asta Medica, Frankfurt, Germany) to induce testicular regression and lower epididymal androgens, while a control group received only vehicle. Epididymides were removed 16 and 25 days after treatment, and sperm heads were analysed by a computer‐assisted morphometric analyser. Cluster analysis revealed swollen sperm head cells in proximal regions 1 and 2 of the epididymis, but fewer such forms distally. Normal head shapes became the majority in region 4 and these underwent a gradual but statistically significant decrease in size (area, perimeter, length, width) and shape as they reached the distal regions. In the animals given Cetrorelix, sperm with swollen heads were found more distally than in the controls, although they were also never present in the distal cauda (region 6). Normal heads still became predominant in region 4 after 16 days treatment, and in region 6 after 25 days. The normal forms in the cauda epididymidis of treated animals were significantly larger than cells from control animals. We conclude that epididymal sperm maturation in the monkey is characterised by both a loss of sensitivity to distortion on air‐drying, and by a decrease in sperm head size. The former, but not the latter, is attained by sperm in androgen‐deficient epididymides from GnRH‐antagonist‐treated monkeys. Am. J. Primatol. 51:103–117, 2000. © 2000 Wiley‐Liss, Inc.