Table 1.

Chromosome analysis of B6D2F1 oocytes fertilized by ICSI with fresh, frozen, or freeze-dried B6D2F1 spermatozoa: Comparison of different media for sperm dispersion and storage

Medium for sperm dispersion and storage	Sperm treatment	Final freezing temp., °C	Sperm storage		No. oocytes analyzed (No. exps.)	No. chromosome aberrations per oocyte	No. (%) oocytes with normal karyotype
			Temp., °C	Time, days
Hepes-CZB	Fresh	—	—	—	145 (9)	0.083	134 (92)a
	Frozen	−196	−196	<1	58 (4)	1.00	37 (64)a
CZB	Frozen	−196	−196	<1	118 (7)	0.41	96 (81)b
	Freeze-dried	−196	4	2 to 63	63 (4)	1.2	33 (52)b
NaCl/EGTA*
50 mM/50 mM	Fresh	—	—	—	98 (4)	0.07	91 (93)c
	Frozen	−20	−20	Up to 14	51 (4)	0.67	37 (73)c
	Frozen	−75	−75	Up to 14	63 (4)	0.10	58 (92)
	Frozen	−196	−196	<1	63 (4)	0.16	56 (89)
	Freeze-dried	−196	4	Up to 21	105 (9)	0.43	87 (83)d,e,f
20 mM/50 mM	Freeze-dried	−196	4	Up to 28	89 (4)	0.72	60 (67)d
80 mM/50 mM	Freeze-dried	−196	4	Up to 14	52 (4)	1.2	28 (54)e
50 mM/10 mM	Freeze-dried	−196	4	Up to 21	65 (5)	3.9	12 (18)f

Statistically significant χ² comparisons, comparing same letters:  

^a,  

^b,  

^e, and  

^f, P < 0.001;  

^c, P < 0.01;  

^d, P < 0.025. 

^*Various concentrations of NaCl and EGTA in 10 mM Tris⋅HCl buffer, pH 8.2–8.4.