Influence of Light and Agitation on Bovine Spermatozoa Stored with Protective Agents

Bovine spermatozoa were stored at 5 C in the Cornell University Extender (CUE) consisting of 20% egg yolk medium and exposed to 2,150 lux of illumination. Viability of spermatozoa following agitation and exposure to light was determined in a series of factorially arranged experiments combining the effects of catalase, N~ gassing, spectral filtering of the light, and the radiation-protective agent, fl-mercaptoethylamine (MEA). Both light and agitation were spermicidal (P < .01). The two factors interacted dramatically, causing rapid inmmbility of spermatozoa stored in the air, whereas progressive motility in other treatments was retained for more than 12 days. Replacement of air with N~ in sealed glass ampules was highly effective and catalase was partially effective in negating this harmful effect on motility of spermatozoa (P < .01). Attempts to remove all traces of 0_~ with MEA were thwarted by toxicity of MEA to spermatozoa. These results indicate that only part of the damaging effect of 0: is catalase specific (H~O2 formation), and that other harmful mechanisms may be inhibited by replacement of air with N~. Spectral filtering of white light revealed that the blue region was particularly danmging to spermatozoa and to catalase. The spectral characteristics of the cytochromes suggest that these heine proteins, like catalase, may be particularly sensitive to the blue light and serve as photon acceptors, thus initiating a series of photochemical reactions damaging to the cell. Survival time of bovine spermatozoa is decreased in the presence of high levels of O~ (13, 14), large air spaces in storage tubes for semen (13), and agitation of these tubes during storage (12). Depression of motility appears to be due, in part, to the formation of hydrogeu peroxide, and replacement of the air with inert gas or CO: (5, 9, 11, 13) often is beneficial.