本篇用酸性Tyrode's 溶液在332個二細胞期的老鼠胚胎之透明帶上鑽洞，以觀察其在實驗室中的孵化情形。透明帶上鑽洞是在人類輸卵管液的培養液中進行的。比較實驗組和未施以顯微操作的對照組中之335 個老鼠胚胎之間孵化的情形。二組在培24小時或72小時，並無差異。由此顯示，對胚胎施以輔助孵化操作，並不會造成胚胎之傷害。培養72，96，120 和144 小時以後，孵化的比例在兩組之間有明顯的差異( P 值小於0.01)。經過顯微操作的胚胎通常提早一天孵化，因為有110(33.1%)個胚胎孵化，比起對照組祇有1 (0.3%) 個胚胎孵化來得多。同時，在第4，5，6 天經過顯微操作的胚胎，孵化數目比對照組多。本實驗結果顯示，顯微操作並不會影響胚胎發育，並可以提升孵化的過程；此外，較多的胚胎會進行孵化而且孵化會提早發生。
Hatching in vitro was studied following zona
drilling of 332 two-cell mouse embryos using the
method of acidic Tyrode's solution. Zona drilling
was performed in the human tubal fluid culture
medium. Hatching was compared to 335 unmicro-manipulated controls. There were no significant
differences between these two groups either at
culturing for 24 hours when 4-8 cell embryos were
observed or at 72 hours when blastocysts were
observed. This indicated that micromanipulation
itself was not harmful to the developing embryos.
The incidence of hatching significantly differed
between groups after culturing for 72, 96, 120, 144 hours, respectively. Hatching usually occurred a day earlier in micromanipulated embryos as 110/332 (33.1 %) had started extruding on day 3 as
compared to 1/335 (0.3%) in control group
(P<0.05). Furthermore much more embryos had
started hatching in the micromanipulated embryos
on day 4, 5, and 6 as compared to the control
group. Results indicate that the hatching process is enhanced by the micromanipulation procedures;
more embryos start hatching, and extrusion occurs
earlier.
