Intracytoplasmic Sperm Injection (ICSI) in Cattle and Other Domestic Animals: Problems and Improvements in Practical Use.

Abstract

Intracytoplasmic sperm injection (ICSI) is the [8][9][10].In human ICSI, high fertilization and pregnancy rates were achieved when a motile spermatozoon was injected after immobilization [6]. Dramatic advances in the treatment of severe male-factor infertility have been achieved by using ICSI, and at present, the technique of ICSI is being widely used in clinical applications for human infertility.In cattle, the first ICSI calves were born in 1990 in Japan [4]. These results showed that bovine embryos produced by ICSI with a dead (killed) bull spermatozoon could develop into live calves. The normality of the calves (growth, behavior and reproduction) was also reported after five years [11]. However, the cleavage rate of oocytes after ICSI was very low (12 percent, 61/ 507) [4], the production rate of transferable embryos was low for practical use [4,[12][13][14][15][16][17][18][19][20][21][22][23][24]. In other domestic animals (pig, horse and sheep), the cleavage rate of ICSI oocytes was also low [20,[24][25][26][27][28][29][30][31][32].There are many excellent reviews on the current status and future of ICSI in humans [33], mice [34] and domestic animals including cattle [35][36][37][38][39][40], and this pa--Reviewper reviews the problems with and improvements to ICSI for practical use in domestic animals, especially in cattle.

A combined treatment of ionomycin with ethanol improves blastocyst development of bovine oocytes harvested from stored ovaries and microinjected with spermatozoa

“…However, blastocysts/ 235 cleavage rate in our study (30%) is comparable to that reported by Wei and Fukui [12] (32%) which indicates that a failure in the early post-fertilization events -from fertilization until cleavage-is the main determiner to the successful development after bovine ICSI. Application of additional activation stimuli to the bovine ICSI oocytes have been considered important for decondensation of sperm heads, pronuclear formation, cleavage and embryonic development [8,35]. Since induction of 240 abnormally high frequent and/or prolonged calcium elevation may trigger premature termination of embryonic development [36], the additional activation stimuli better to mimic the mechanism induced during normal fertilization without affecting other oocytes metabolic pathway.…”

Activation with Ethanol Improves Embryo Development of ICSI-Derived Oocytes by Regulation of Kinetics of MPF Activity

“…Such incorporation of the sperm head into the ooplasm results in release from meiotic arrest of the oocyte. In the case of ICSI, the soluble sperm factors are the only oocyte activation factors, except for the physical stimulation of the injection procedure [37].…”

Intracytoplasmic sperm injection in domestic and wild mammals

“…For this reason, it is not necessary to employ additional protocols to induce oocyte activation and subsequent embryo development. Nevertheless, it is not the case for some large domestic species, whose development to blastocyst and even more to term is extremely low (reviewed by Horiuchi & Numabe 1999).…”