Research On The Effect Of Ovulation Induction By Letrozole On The Mouse Pinopode Growth

Objective:Ovulation induction in assisted reproductive technology is the most important and crucial procedure.The traditional ovulation medicine has many shortcomings,e.g.a lower clinical rate of pregnancy,perhaps leading to ovarian hyperstimulation syndrome(OHSS),and so on.Ovulation new drugs-the third-generation non-steroidal aromatase inhibitor letrozole(LE),its role in ovulation induction has been gradually recognized.But until today,the research of endometrial receptivity in the ovulation cycle by LE still very little.The correlation between LE and the growth of endometrium can not be determined.Do not know the answer about the shift of the implantation window in the ovulation cycle by LE. Do not know the best clinical dose of LE too.Mice in this experiment as a model, focusing on the development of pinopodes in peri-implantation period,tried to answer the above-mentioned issues,with a view to LE ovulation induction to provide further experimental evidence.Methods:The object of study are mature female Kunming mice,mating had not,having two consecutive normal estrous cycle by vaginal smear observed.These mice were randomly divided into natural cycle group(NC group),LE2.5 group and LE5.0 group,12 in each group.The two doses drug program(2.5mg/d×5d, 5.0mg/d×5d) of LE,converted to equivalent doses of experimental animals.LE were administered to fills the stomach of the mice in the third observation proestrus. Separately in D3.5,D4.5 to various treatment groups be sampled and detected: Removal of the eyeball method to blood;the method of enhanced chemiluminescence enzyme immunoassay(ECLIA) using to determine the estradiol and progesterone levels;either side of the mid 1/3 of the cornua uteri be cut,tested by the scanning electron microscopy(SEM),observing the development of pinopodes in the endometrium;and the number of corpus rubrum of each mouse be counted. Results:Three groups of female Kunming mice(LE 2.5mg/d×2d group, LE5.0 mg/d×2d group and the NC group) the number of ovulation were no significant differences(P=0.635,P＞0.05).Each mouse the number of follicles (corpus rubrum)in one ovulation is about 15.Each group of D4.5 of the concentration of estradiol was slightly higher than the same group of D3.5,but no significant.The level of progesterone of D4.5 was higher then the same group of D3.5,and P values were Less than 0.05(P＜0.05),the difference was statistically significant.Levels of both estradiol and progesterone hormone are no significant differences between the three groups during the same period(P＞0.05).The result indicated as follows:the individual difference of the concentration of estrogen in the implantation window in the ovulation cycle by LE,was not large than in the natural cycle,also did not interfere with the progesterone levels normal increase in luteal phase.Each group of D4.5 of the mean score of the pinopodes(pp) was slightly higher than the same group of D3.5,and P values were P＜0.01,the difference was very significant.However,the mean score of the pp are no significant differences between the three groups during the same period(P＞0.05). The result suggests as follows:The formation and development of models of pp in the ovulation cycle by LE,compared with the NC cycle,has not changed,and has little to do with the dose of LE.Conclusion:LE is an effective drug for ovulation induction.LE had a less influence on the function of Corpus luteum.Does not increase the individual difference about these levels of both estradiol and progesterone hormone which regulated the development of endometrial.The growth,development,synthesis and secretion of the endometrium in the ovulation cycle by LE were normal.And can timely transform to the state of adhesion.The differences of the formation and development model of morphological markers(pp) of Endometrial receptivity in the ovulation cycle by LE are small.It is not a statistically significance.Without the existence of the relationship between dose-response gradient.It is proved that the implantation window in the ovulation cycle by LE does not move.In addition,it is a rationalization proposal choosing the low doses of 2.5mg/d×5d LE program in assisted reproductive technology.