Abstract
This study was designed to examine whether hyaluronic acid improved development of the electro-activated porcine diploid eggs. In-vitro matured oocytes were subjected to a single square pulse of direct current for 100 μsec at 1,500 V/cm for activation. The activated eggs were treated with 5 μg/ml cytochalasin B for 4 h. Eggs with only the first polar body that were judged as diploids were further cultured either in the modified KRB solution (mKRB) or Whitten's medium, each with or without addition of 0.5 mg/ml hyaluronic acid. The frequency of eggs developed to blastocysts was significantly higher in Whitten's medium (12% at 144 h and 14% at 168 h after electro-activation) than in mKRB (6% both at 144 h and 168 h) (P<0.05). The frequency of development to blastocysts increased to 13% in mKRB and to 28% in Whitten's medium by addition of hyaluronic acid when measured at 168 h. At this time, frequencies of abnormal eggs were lower in both media in the presence of hyaluronic acid. Expanded blastocysts were observed at 168 h but only when the medium included hyaluronic acid. There were no significant differences in the mean number of cells per blastocyst among the four media, and the number of cells per blastocyst ranged from 21 to 61 at 168 h.
