Table 1. Toxicity of hyaluronidase, ALT-BC4, and Hirax in relation to embryonic development

Group1)	No. of oocytes	Rate of embryo development (%)
		2-cell	4-cell	8-cell	16-cell	Morula	Blastocyst
2S2)	107	96.0 ± 2.0	84.0 ± 4.7	70.4 ± 8.0	58.9 ± 3.5	52.6 ± 4.9	52.6 ± 4.5
10S	100	96.3 ± 1.3	84.8 ± 1.5	70.7 ± 1.8	58.3 ± 2.0	50.7 ± 1.4	50.7 ± 1.4
20S	104	96.9 ± 2.0	85.2 ± 4.1	65.5 ± 8.3	51.8 ± 9.8	47.7 ± 9.5	47.7 ± 9.5
10A	115	95.8 ± 2.3	85.9 ± 5.6	70.3 ± 9.9	59.2 ± 10.4	54.0 ± 9.5	53.3 ± 8.7
20A	111	96.3 ± 1.9	86.1 ± 4.8	75.6 ± 2.5	61.4 ± 3.9	58.5 ± 5.2	58.5 ± 5.2
10H	102	92.5 ± 2.0	82.4 ± 0.9	69.8 ± 0.5	55.8 ± 3.4	50.4 ± 5.2	50.4 ± 5.2
20H	116	94.9 ± 0.7	89.2 ± 1.9	77.8 ± 4.6	57.5 ± 4.8	50.4 ± 8.2	50.4 ± 8.2

The cumulus-oocyte complexes (the COCs) were denuded using 800 U/mL hyaluronidase for 10 (10S) and 20 min (20S); ALT-BC4 for 10 (10A) and 20 min (20A); and Hirax for 10 (10H) and 20 min (20H). Values are expressed as the mean ± SEM (n = 3).
Positive control (2S), the traditional denuding method that removed cumulus cells from oocytes using 800 U/mL hyaluronidase for 2 min.