Photosensitive chemical and laser light treatments decrease epizootic hemorrhagic disease virus associated with in vitro produced bovine embryos

Photoinactivation was employed to eliminate EHDV-2 from in vitro produced b ovine embryos experimentally exposed to this virus. Immature oocytes were m atured, fertilized, and cultured in chemically defined conditions. All trea tments were performed on zygotes. Developmental potential of zygotes and ce ll numbers of resulting hatched blastocysts were assessed after exposure to a 1 mW helium neon laser (633 nm, red) for 1, 5, 10, and 15 min; the photo sensitive chemicals hematoporphyrin (15 muM) and hypericin (1 and 10 muM) f or 15 min; a combination of 10 muM hypericin and laser light for 1, 3, or 5 min; and a combination of 15 muM hematoporphyrin and laser light for 1, 2, or 3 min. There were no significant differences among proportions of embry os developing or cell numbers after treatment with or without exposure to l aser light alone for up to 10 min. No differences were observed after expos ure of zygotes to photosensitive chemicals alone. Exposure to 10 muM hyperi cin and 5 min of laser light or 15 muM hematoporphyrin and 2 min of laser l ight compromised zygote developmental potential. After exposure to 10(6) TC ID50/mL EHDV-2 for 90 min groups of 10 zygotes were exposed to 10 muM hyper icin or 15 muM hematoporphyrin and laser light to inactivate the virus. Hem atoporphyrin was effective with 3 min light exposure at reducing the percen tage of EHDV-2 contaminated zygote pools (16.7%) as compared to EKDV-2 expo sed pools without treatment (88.9%) but hematoporphyrin + 1 min light was i neffective. intermediate effect (55.6%). (C) 2001 by Elsevier Science Inc.