Methods for assessing sperm motility, morphology, and counts in the rat, rabbit, and dog: A consensus report.
In an effort to facilitate data sharing and interlaboratory interpretation of reproductive toxicity, studies involving sperm motility testing optimal methods for such testing in rats, rabbits, and dogs were discussed by a working group convened by the ILSI Risk Science Institute as part of its cooperative agreement with the US Environmental Protection Agency, Office of Pesticide Programs. The consensus report reached by the working group was described in this article. Based on past studies the working group concluded that sampling from either the vas deferens or from the cauda epididymis was adequate for studies of rat sperm motility. It was stressed that optimal sampling would, however, be dependent upon the age and sexual activity of the rat as well as on the particular question being addressed. The group also recommended the diffusion method rather than the aspiration method for sperm collection and limiting manipulations associated with shear stress. It was suggested that strict temperature control was not necessary but maintenance of temperatures within the range of room temperature to 37 degrees-C during tissue processing and sperm collection and from 34 to 37 degrees-C during analysis was recommended. Other recommendations included the use of any physiologic buffered saline solution at physiologic pH with the addition of 0.5 to 1% bovine serum albumin, the use of 40 to 50 micron deep sample chambers, and measurements of velocity as well as percent motility values. Recommendations for sample preparation for morphology, classification of morphology, and rat sperm counts, and for rabbits and dogs, were presented. Future directions in this field were discussed.