Effects of the oviduct and wheat germ agglutinin on enzymatic digestion of porcine zona pellucidae.
Seventy-two crossbred gilts were utilized to examine whether the oviduct rendered zona pellucidae resistant to protease digestion, whether the uterus reversed this resistance and whether such a uterine reversal was necessary for hatching. Oocytes were aspirated from follicles 22 to 28 h after onset of estrus (d 0); oviductal and uterine oocytes or embryos were collected on d 1 to 6. These oocytes and embryos were subjected to a solution containing .1% trypsin and .1% pronase (37 degrees C) for observation of zona pellucidae digestion. Zonae of oviductal oocytes were more (P less than .001) resistant to digestion than were follicular oocytes. Placement of follicular oocytes in oviducts for 30 min rendered zona pellucidae more (P less than .001) resistant to protease digestion than oocytes not exposed to oviductal secretions. Resistance of zona pellucidae to proteases, however, decreased (P less than .001) after entry into the uterus. Zonae of morulae retained in oviducts took longer (P less than .001) to digest than those recovered from the uterus. Blastocysts also were treated with wheat germ agglutinin (WGA; 50 micrograms/ml) for 40 min to determine whether artificial induction of zona resistance to enzymatic digestion affected the ability of embryos to hatch. Though WGA treatment delayed (P less than .001) enzymatic digestion of zona pellucidae, time from collection to hatching was not affected. This experiment indicated that the oviduct delayed enzymatic digestion of the zona pellucidae, whereas the uterus reversed this delay. The re-establishment of enzyme susceptibility after uterine entry, however, appeared to be unrelated to the subsequent ability of blastocysts to hatch.
Broermann
D M
DM
Dept. of Anim. Sci., Ohio State University, Columbus 43210.
Xie
S
S
Nephew
K P
KP
Pope
W F
WF
D000818:Animals; D005187:Fallopian Tubes / Q000502:physiology*; D005260:Female; D010063:Ovum / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D013552:Swine / Q000502:physiology*; D014599:Uterus / Q000502:physiology; D014909:Wheat Germ Agglutinins / Q000378:metabolism*; D015044:Zona Pellucida / Q000378:metabolism*
D014909:Wheat Germ Agglutinins; D010447:Peptide Hydrolases