Study Of The Relationship Between Sperm DNA Integrity And Early Spontaneous Pregnancy Loss

ObjectiveSpontaneous pregnancy loss (SPL) is a common obstetrical disease, accounting for 10-20% of clinical pregnancy. It happens mostly in the early stage (during the first three months) of pregnancy. The mechanisms are complicated, involving genetical, anatomical, immunological, endocrinological and infectious factors, tendency of thrombosis, enviromental pollution and many other unknown causes. Most of the present researches have been focusing on probing the problems of the female. However, the pathogens of over 50% cases can not be found, although detailed examinations have been carried for the female. It has been shown that chromosomal or genetic abnormalities are the main causes of early spontaneous pregnancy loss. Also the times of pregnancy loss showed no correlation with embryonic chromosomal or genetic abnormalities. But chromosomal analysis of peripheral lymphocytes can only provide the reasons for 2.4-5% of the spontaneous pregnancy losses, indicating to detect the chromosomal or genetic abnormalities during gametal stage may be more effective. As the vector of the paternal genetic information, sperms contain about half of the genetic plasm in the embryo, and for the convenience of obtaining; it may be a good material to study the DNA injury in the gamete. Acridine orange(AO) is a fluorescent dye, which can bind with the double strand DNA showing green fluorescence, and bind with single strand or fractured DNA showing red fluorescence. As the DNA injury in sperm shows double strand fracture or single strand formation, AO staining is an ideal assay to assess the sperm injury. In the present study, we used sperm DNA integrity (SDI) as a evaluating indicator of sperm DNA injury to probe its relationship with early spontaneous pregnancy loss (ESPL). Materials and MethodsThe outpatients of our hospital during March 2009 and Januray 2010 were chosen as the study objects.The patient group were 70 cases with ESPL excluding the causes of exogenic actions, and the control group included 110 cases of infertile cases, which were caused by doulbe salpingemphraxis of the female, excluding the cases of ovarian failure. The males in both of the two groups did not have fevers or take medicines.The sperms were detected by AO staining. As Evensen et al have proven that the DNA fragment index (DFI) of all normal male should be less than 30%, and the SDI in the present study meaned 1-DFI, the cases with sperm DNA intergrity no:more than 70% were regarded as abnormal.ResultsIn the 70 cases of the patient group,32 ones showed abnormal SDI, accounting for 45.7%, with the average SDI rate of 50.6%. The normal 38 cases accounted for 54.3% and the average rate of SDI was 83.3%. The average rate of SDI in this group was 70.5%.Among the 110 cases in the control group,25 ones showed abnormal SDI, accounting for 22.7%, with the average SDI rate of 51.4%. The average of SDI in the 77.3% normal remainings (85 cases) was 85.9%. The average SDI rate in this control group was 79.1%.ConclusionThe rate of abnormal SDI in the group with ESPL was much higher than that of the infertile control group. The differences between the two groups were statistically significant (P>0.05), suggesting there were obvious sperm DNA injury in the patient group, which could seriously affect the embryo quality, resulting in ESPL. Taken together, the abnormal SDI may one of the main resons of ESPL Meanwhile.