Objective: To investigate the expressions of peripheral lymph node addressin(PNAd) and GlcNAc-6-sulfotransferase (GlcNAc6ST) in endometrium and their impacts on implantation.
Methods: PNAd expression in endometrium was examined by immunohistochemistry and Western Blot from 75 women (12 from healthy women, in proliferative phase; 63 from sterile women, of whom, 27 were in early-secretory and 36 in mid-secretory phase). GlcNAc6ST mRNA was examined by real-time PCR in 41 sterile women. The 63 sterile women had underwent IVF-ET and were consequently divided into clinical pregnant (29 cases) and nonpregnant (34 cases) groups.
Results: (1) PNAd localized to the membrane and cytoplasm of luminal and glandular epithelia. Staining was patchy and much less intense during the proliferative phase than during the secretory phase. In Western Blot of PNAd, four bands appeared, which were Sgp200, CD34, MAdCAM-1, GlyCAM-1 respectively, and each was positively correlated with the others significantly. The former three molecular levels were significantly higher during the secretory phase as compared with the proliferative phase. Message RNA of GlcNAc6ST was positive in all cases and showed no correlation with any component of PNAd. (2)The expressions of CD34 and GlyCAM-1, but not Sgp200 and MAdCAM-1, were significantly higher in pregnant women than in nonpregnant ones. However, the GlcNAc6ST mRNA level did not differ between groups. (3) No significant difference was found in female age, methods of fertilization, thickness of endometrium on day hCG, cumulative embryo score(CES) and mean score of transferred embryo(MSTE) between the groups.
Conclusion: PNAd expression in the human endometrium fluctuates with the menstrual cycle. Elevated CD34 and GlyCAM-1 during the secretory phase might be stimulative factors for embryo implantation. Defect in PNAd expression may account for a portion of unexplained infertility.