بررسی علل توقف جنین‌های پیش از لانه‌گزینی و راه‫کار‌های غلبه بر آن‬‬‬‬

هدف: در این مطالعه به بررسی عوامل محرک توقف تکوین جنین و راه‌های مقابله با آن در راستای هموار ساختن راه برای تحقیقات در این زمینه و افزایش بازدهی روش ivf، پرداخته‌ می‌شود.مقدمه: لازمه داشتن یک جنین سالم، طی شدن صحیح مراحل تکوینی آن است. هر گونه اختلال در این مراحل می‌تواند باعث توقف تکوین پیش از لانه‌گزینی و نا‌باروری شود. یکی از تکنیک‌های رایج کمک باروری، لقاح آزمایشگاهی (ivf) است که کاربرد فراوانی دارد؛ اما نزدیک به 50 درصد از جنین‌های حاصل به مرحله بلاستوسیست نرسیده و دچار توقف می‌شوند که این توقف با عدم تقسیم سلولی به‌مدت حداقل 24 ساعت مشخص می‌شود. جنین‌های متوقف شده را می‌توان به سه دسته تقسیم کرد: دسته اول، با اختلال در فعال شدن ژنوم جنینی؛ دسته دوم و سوم با سطوح پایین گلیکولیز و سطوح متغیر فسفریلاسیون اکسیداتیو شناخته می‌شوند.نتیجه‌گیری: توقف تکوین پیش از لانه‌گزینی به دلایل مختلفی ایجاد می‌شود که ممکن است دارای منشا جنینی یا والدینی باشد. ازجمله راه‫کار‌های غلبه بر این مشکل می‌توان به انتقال دوک مادری/ انتقال هسته‌ای، بهبود محیط کشت و استفاده از آنتی‌اکسیدانت‌ها، سنتز complementary rna (crna) /small interfering rna (sirna) اشاره کرد. علاوه بر این، تاثیر عوامل بیرونی ازجمله شرایط آزمایشگاه، روش انجام فرایند‌های کمک باروری (art) و نقش پزشک باید در نظر گرفته شود. شناسایی کامل دلایل ایجاد کننده توقف تکوین ‌جنینی و راه‫کار‌های غلبه بر آن‌ها، می‌تواند باعث بهبود فناوری‌های مورد استفاده در درمان و افزایش بازدهی روش ivf شوند.

evaluation of the causes of pre-implantation developmental arrest and ways to overcome it

aim: in this review article, we intend to investigate and review the factors that lead to embryonic developmental arrest and explore different strategies to address this phenomenon. we aim to pave the way for further research in this field and enhance the efficiency of the ivf method for infertility treatment. introduction: to ensure proper embryonic development, embryos need to progress through their developmental stages unimpeded. any disruptions in these stages including oocyte factors, sperm factors, and embryonic factors can result in infertility due to pre-implantation developmental arrest. therefore, it can be very helpful to understand the effective factors behind this phenomenon. topic: among couples attempting to conceive, infertility persists despite their best efforts. couples are typically considered infertile if they have tried to conceive for twelve months without success and without using protection; but if the woman is over 37 years old, this twelve months will be reduced to six months. assisted reproductive techniques (art) encompass various methods that are aimed at aiding these couples in overcoming infertility. this definition includes any manipulation of embryos and eggs for infertility treatment. assisted reproductive techniques include in vitro maturation (ivm), in vitro fertilization (ivf), and intracytoplasmic sperm injection (icsi). among these, ivf/icsi is particularly effective in treating couples infertility. however, one common challenge in this process is embryonic developmental arrest during the pre-implantation stages, a primary cause of infertility in treatment cycles. approximately 40 to 50 percent of ivf cycles do not progress to the blastocyst stage and arrest. this arrest characterized by a lack of cell division for at least 24 hours. most embryonic arrests occur on the second and third day after fertilization, during the two to eight-cell stages. these arrested embryos retain their developmental potential, and their gene expression program related to their arrested stage remains unaffected. arrested embryos can be classified into three categories: those with impaired activation of the embryonic genome (ega), those with low levels of glycolysis, and those with variable levels of oxidative phosphorylation. solutions to overcome embryonic developmental arrest include maternal spindle transfer (mst)/nuclear transfer (nt), optimizing culture media, employing antioxidants, and synthesizing complementary rna (crna)/small interfering rna (sirna). conclusion: pre-implantation arrest can result from various factors, either of embryonic, maternal, and paternal origin. among embryonic factors, disturbances in fields like gene expression, mitochondrial activity, methylation patterns, chromosomal abnormalities, small non-coding rnas, and embryonic metabolic status have the most significant impact on embryonic arrest induction. additionally, parental factors, like genetic factors, and infertility etiology can lead to embryonic developmental arrest. external factors, such as laboratory conditions, art methods, and the role of the physician, also play a role in embryonic developmental arrest. while treatment studies for overcoming embryonic arrest are very limited, they are generally based on animal models, which is why it is necessary to conduct more studies and enter the human phase. a comprehensive understanding of the causes of embryonic arrest and solutions to address them can enhance infertility treatment technologies and improve the effectiveness of the ivf method for infertility treatment.