| ObjectiveThis study was performed to establish the selenium(Se)deficiency animal model on Kunming mice and to determine the effect of Se deficiency on reproductive system on hereditism, histology and morphology at corpuscular and molecular level,and to observe the recovery after Se supplement with different doses.The aim was to approach the relationship of the dose of Se supplement and recovery degree,to determine if various priorities to Se in various phase of spermatogenesis.It can provide the theoretical and experimental evidence for supplying selenium in clinic.Methods144 Kunming male mice were randomly divided into four groups:control group,Se deficiency group,supplement group 1 and supplement group 2,36 mice each group.Control mice were administrated on common diet.Other mice were feeding on Se deficiency diet (0.024mg/kg)after ablactation.Supplement group 1 and supplement group 2 mice were supplied with Se on diet from 6th week after ablactation.Respectively,12 mice per group were killed on week 5,7,11 after ablactation.The condition of the mice was observed and the weight was recorded every week.The testis was weighed for the ratio of testis and body of the mice.Se content in testis was determined by Microwave Digestion-Hydride Generation Atomic Absorption Spectrometry.We observed the rate of micronuclei in early spermatid,abnormal sperm rate and the rate of sperm cytoplasmic droplet of the mice,and DNA damage in spermatid and testis cell was determined by single cell gel electrophoresis(SCGE).ResultsSelenium content in testis of the mice administrated on Se deficiency diet significantly decreased on week 5,7 and 11(P＜0.05).It increased after Se supplement,and that in supplement 1 and supplement group 2 was higher than Se deficiency group on week 7,11(P＜0.05).That in supplement 1 got to the level of the control on week 7(P＞0.05),and was higher on week 11 (P＜0.05).That in supplement 2 was higher than the control on week 7,11(P＜0.05).There was no obvious difference between supplement 1 and group 2.The weight of mice increased gradually from 1st week after feeding on Se deficiency diet, being lower than the control.And it has no significant changes after Se supplement.In Se deficiency group,the weight of testis was remarkably lower than the control on week 5,7,and 11(P＜0.05),but the ratio of testis and the body of the mice was at the higher level(P＞0.05). After Se supplement,the weight of testis has no obvious change occurred,and was still significantly lower than the control on week 7(P＜0.05),and increased on week 11(P＞0.05).The ratio has no significant changes.By observing the rate of DNA damage in spermatid and testis cell,micronuclei in early spermatid,abnormal sperm rate,and the rate of sperm cytoplasmic droplet of the mice,we found that these damages increased in Se deficiency group on week 5,7,and 11(P＜0.05),and decreased gradually after Se supplement.It showed that DNA damage in spermatid and testis cell by SCGE decreased in supplement 1 and group 2 on week 7,11(P＜0.05).The damage was revealed by comet total length,tail length,TM and OTM etc.The damage in testis was still higher than the control on 7th week(P＜0.05),reaching at the control level on 11th week (P＞0.05).However,that in spermatid of supplement group 1 mice got to the control level on 11th week(P＞0.05),and that in supplement 1 and group 2 was higher than the control on both 7 and 11 week(P＜0.05).The rate of micronuclei in early spermatid in supplement 1 and group 2 was lower than Se deficiency group on week 7(P＞0.05),11(P＜0.05).It was high significantly on 7th week(P＜0.05),getting to the control level on 11th week(P＞0.05)as compared to the control. Abnormal sperm rate decreased after Se supplement,and it was remarkably lower than Se deficiency group on week 7,11(P＜0.05)in supplement 1 and group 2,reaching at the level of the control(P＞0.05).The change of the rate of abnormality in end of sperm was as the abnormal sperm rate.The rate of sperm cytoplasmic droplet was significantly lower than Se deficiency group after Se supplement,the rate in head decreased greatly on 7th week(P＜0.05),and it in tail decreased slightly(P＞0.05),both decreased markedly on 11th week(P＜0.05).Compare with the control,the rate of sperm cytoplasmic droplet in head of supplement 1 group was high on week 7, 11(P＜0.05),it in tail was high on 7th week(P＜0.05),and was as the level as the control on 11th week(P＞0.05).Both in head and tail of supplement 2 group were higher than the control on 7th week(P＜0.05),getting to control level on 11th week(P＞0.05).There were no significance between supplement 1 and 2 group,except the percentage of abnormality in end of sperm,it was lower in supplement 1 group than supplement 2 group on week 7,11(P＜0.05).Results were shown in photomicrographs of testis section from all the four groups. Shrinkage of seminiferous tubules was seen in Se deficiency group as compared to the control testis.Decrease in the germinal height and increase in the central lumen size was also observed in Se deficiency group.There was appreciable decrease in the spermatid and mature sperm number in Se deficiency group along with a reduction in the pachytene spermatocytes. Compared to Se deficiency group there was no significant changes in supplement 1 and group 2, and the number of sperm in tubules almost did not rise to the control level.ConclusionSe deficiency on mice can cause pathological changes in testis,dyszoospermia, paramorphia of sperm,DNA damage.Se supplement can lead these damages to recover except for growth delay and pathological changes.There were various priorities to Se in various phase of spermatogenesis.There was no significant difference of selenium supplement with 0.224mg/kg and 1.224mg/kg in short time.
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