Effect Of CdCl₂ On Sperm Toxicity And Sex Ratio In Mouse And Bovine

This paper studied on male reproduction, IVF, embryo development of bovine and mouse culturing in medium with cadmium in vivo and in vitro; meanwhile, through designed primer of Y-specific chromosome gene of bovine and mouse identified the sex of embryos, discuss the influence of cadmium on sex differentiation of bovine and mouse IVF embryos. The result shows:1 Injection 0, 0.5, 1 and the 2mg/kg-w CdCl₂ to male mouse, according to the body weight, once every day, continuously 5 weeks. Result shows mouse body weight and gonad weight drop obviously, indicated that cadmium have toxicity on mouse growth and the reproduction, and present dosage dependence relations. The quality of sperm was studied after treated with CdCl₂, shows sperm concentration and motility drops tendency along with the CdCl₂ injection dosage and the time increase, sperm deformity rises (P<0.05); When CdCl₂ injection dosage achieves 2mg/kg-w, no moving sperm basically in epididymis, indicate cadmium has obvious toxic affection to the forming and quality of mouse sperm. Mouse reproduction experiment shows groups treated with CdCl₂ have lower breeding ability; the pregnancy rate of female mouse drops too (P<0.05); Litter size and weight at birth was lower than control (P<0.05).2 Bovine sperm incubate with cadmium during capacitation in vitro, the content of cadmium to be 0, 1, 2 and 4mg/L separately. Result shows, cadmium concentration and incubate time both drop the quality of sperm; sperm motility have downward trend as the increase of concentration and incubate time. Comparing with control, the group treated with 4mg/L CdCl₂ is significant (P<0.05), assumes the dosage dependence and the time dependence relations.3 Carries on bovine and mouse IVF with sperm incubated with cadmium, the content is 0, 1, 2, 4mg/L separately, study the influence of cadmium on IVF and embryo development in vitro. Result shows, each group treated with cadmium, the IVF rate is lower than control. When compares with control, low dosage group is not significance (P>0.05),middle and high dosage groups have significance (P<0.05), indicate cadmium has obvious toxic effect on mammal's IVF; higher cadmium dosage is, stronger toxicity is. Study also shows cadmium has obvious toxicity on bovine and mouse early embryo's development, depressed the cleavage and development of the early embryos, reduced the forming rate of blastocyst. The cleavage rate and IVF rate of groups treated with cadmium are lower than control (P<0.05), 8-cell rate and blastocyst rate are obviously reduced (P<0.05), abnormal embryo increased too, presented dosage dependence relations.4 Injection 0, 0.5, 1 and the 2mg/kg-w CdCl₂ to male mouse, according to the body weight, once every day, continuously 5 weeks. Then breed with female together, study the influence of cadmium on mouse offspring sex differentiation. Result shows groups treaded with cadmium have higher female sex rate than normally (1:1). Group of high dosage (2mg/kg·w) is significant when compare with control (P<0.05), but middle dosage group (0.5mg/kg·w) and low dosage group (lmg/kg·w) have no significant (P>0.05).5 A pair of bovine male-specific PCR primer Y1/Y2 was designed based on the sequence of bovine Y-specific repeat sequence from GenBank; based on bovine satellite DNA designed a pair of bovine specific primer N1/N2 as internal control primer. Meanwhile, based on mouse Y-specific repeat sequence from GenBank designed a pair mouse male-specific PCR primer M1/M2. After PCR amplification of bovine and mouse genome DNA and IVF embryos under the same PCR condition in this study, all have obtained steady and ideal amplification results, keep at the expectant result. In practical application, the routine phenol extraction DNA method could be replaced by cooking extraction DNA method in water, satisfied the request of DNA template in PCR amplification of sex identification, and it's convenient, quick and cheap. Utilized primers designed above to identified the sex of bovine and mouse IVF embryos, result shows, cadmium works on mammal's...