Effects of radiocobalt irradiation of rabbit spermatozoa in vitro on fertilization and early development

Summary. Exposure of rabbit semen to X-irradiation did not reduce the fertilization rate until doses of >25,000 r were used, although motility was noticeably affected at 15,000 r. Evidence of a depressant effect of much lower doses of X-irradiation on the fertilizing ability of rabbit spermatozoa was obtained, however, by using a more sensitive system in which irradiated aliquots from an ejaculate were inseminated mixed together with an exactly equivalent volume of untreated semen from the same ejaculate. Under these competitive conditions the fertilizing ability of spermatozoa was found not to be affected by a dose of 10,000 r, but was significantly depressed (P<0\m=.\01)by 15,000 r, as judged by an increase in the proportion of normally developing to retarded ova, recovered 50 hr after an ovulation injection of hcg. It appears that this depressant effect is exerted at the site of fertilization rather than on sperm transport. X-irradiation of spermatozoa did not increase polyspermic or delayed fertilization, neither did irradiation have any significant effect on the formation of the male pronucleus. A dose response effect was seen at the time of the first cleavage division, for at 24 hr the cleavage rate of control ova (68\m=.\5%) was similar to that of ova fertilized by spermatozoa treated with 10,000 r (68%), but only 33% of ova fertilized by spermatozoa treated with 20,000 to 25,000 r had cleaved at this time compared with 78% of their controls. At 29 and 50 hr several ova fertilized by irradiated spermatozoa remained at the pronuclear stage or at metaphase of the first cleavage division, and even at 50 hr the great majority had only reached the 2-cell stage. Thus, although it is known that cleavage can occur in the absence of the male elements, the first cleavage division does not appear to follow activation of the egg automatically and independently since it has been shown that the state of the male elements introduced at fertilization can influence the rate and ultimate success of the changes which take place at this time.

Section: Discussionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

The Influence of X-Irradiation of Rabbit Spermatozoa on Fertilization and Early Cleavage

Bedford¹,

Hunter²

1968

“…For example, when rabbit spermatozoa were irradiated in vitro with a dose between 400 and 800 r of either X-ray or cobalt 60 (Amoroso & Parkes, 1947;Chang, Hunt & Romanoff, 1957) the embryos fertilized with the irradiated spermatozoa had an increased embryonic death rate. The majority of the embryos fertilized with irradiated spermatozoa failed to develop beyond the blastocyst stage (Dott et al, 1966).…”

Section: Discussionmentioning

confidence: 99%

Embryonic Survival Subsequent to Culture of Rabbit Spermatozoa at 38 and 40 C

Burfening¹,

Ulberg²

1968

Following a preliminary experiment, split ejaculates of rabbit semen, incubated for 3 hr at 38\s=deg\or 40\s=deg\ C, were examined and inseminated separately into the uterine horns of rabbits mated 4 hr previously to vasectomized males. Eggs were recovered and examined for evidence of fertilization 30 hr post coitum. Following return of the eggs to the oviduct their survival was estimated by counting the implantation sites at 9 days post coitum. There was no evidence of any effect of treatment temperature on fertilizing capacity of semen, but embryonic survival rate was higher (75%) in horns inseminated with semen incubated at 38 \ s =d e g \ C than in those inseminated with semen incubated at 40\s=deg\C (53%). Neither fertilization rate nor embryonic survival rate was significantly correlated with semen quality.

“…The insemination of mammalian spermatozoa which have been treated in vitro with X-rays at a dose level of 400 to 800 r results in failure of a large number of eggs to develop beyond the blastocyst stage in rabbits (Amoroso & Parkes, 1947;Chang, Hunt & Romanoff, 1957); mice (Edwards, 1957) and cattle (Rowson & Dott, 1964). Higher doses of X-rays caused development of the eggs to fail at earlier stages (Amoroso & Parkes, 1947;Chang et al,1957;Edwards, 1957).…”

Section: (Received 4th February 1966)mentioning

confidence: 99%

“…Higher doses of X-rays caused development of the eggs to fail at earlier stages (Amoroso & Parkes, 1947;Chang et al,1957;Edwards, 1957). Yet the metabolism and motility of irradiated spermatozoa appear to be unaffected even by much higher doses of X-rays, at least in those species which have been examined (cf.…”

Section: (Received 4th February 1966)mentioning

confidence: 99%

The Effect of X-Irradiation of Rabbit Spermatozoa in Vitro in Different Gases on Egg Development and Sperm Dehydrogenases

Dott¹,

Ishida²,

Chang³

1966

Self Cite

(Amoroso & Parkes, 1947;Chang et al.,1957;Edwards, 1957). Yet the metabolism and motility of irradiated spermatozoa appear to be unaffected even by much higher doses of X-rays, at least in those species which have been examined (cf. Mann, 1964). It seems likely that it is the deoxyribonucleic acid (dna) in the spermatozoa which is affected by X-irradiation rather than their metabolism, motility or fertilizing capacity.X-rays can, presumably, act on dna either directly by virtue of their ionizing activity on dna molecules, or indirectly by producing free radicles. Two of the methods which have been used to protect biological material from the indirect action of ionizing radiation are: (i) performing the irradiation experiment at a low temperature; and (ii) irradiating under anaerobic conditions. The first of these methods was used by Rowson & Dott (1964) Rabbit semen was collected by means of an artificial vagina and diluted with 0-9% NaCl so as to contain lOOx 106 spermatozoa/ml. The diluted semen was then divided into six samples and put into six glass tubes which were filled in pairs with nitrogen, air or oxygen for 10 to 12 min. The oxygen tension was checked with a platinum electrode. The six tubes were sealed and one tube from each of the three pairs was exposed to 800 r at 100 r/min, the other served