术前预测非梗阻性无精子症（NOA）取精结局，有助于筛选出适合进行辅助生殖的患者和避免不必要的手术。但现有睾丸活检、激素检测等方法却难以无创且精准预测。我们前期发现，精浆中外泌体含量丰富，可携带与生精相关的RNA，有望成为突破口。预实验发现，由PRM2、PKM、ACTRT2及FSCN3构建的精浆外泌体mRNA组合在训练集中展现出明显优于激素模型（AUC 0.956 vs. 0.682）的预测效果。据此，我们提出“基于精浆外泌体mRNA标志物组合术前精准预测NOA取精结局”的科学假设。本项目拟在前期已证实4种标志物与人睾丸生精密切相关的基础上，分析NOA模型小鼠睾丸生精状态变化与外泌体mRNA表达量之间的相关性；拟采用外泌体提取、模板扩增及PCR等技术，进一步验证预测模型在内部测试集与独立验证集中的精准性与稳定性，并构建NOA术前决策树。本项目将为术前无创、精准预测NOA取精结局提供新方法。

Preoperative prediction of the sperm retrieval outcome in nonobstructive azoospermia (NOA) helps to screen patients who are suitable for assisted reproduction and avoid unnecessary operations. However, existing methods such as testicular biopsy and hormones detection are difficult to predict noninvasively and precisely. In recent research, we found that seminal plasma was rich in exosomes and could carry RNA related to spermatogenesis, which was expected to be a breakthrough. In the preliminary experiments, we also found that a panel based on seminal exosomal mRNAs, including PRM2, PKM, ACTRT2 and FSCN3, presented a significantly better predictive capacity in the training set in predicting the presence of testicular spermatozoa when compared with current model based on hormones (AUC 0.956 vs. 0.682). Based on this, we put forward the scientific hypothesis that precisely predicting the outcome of sperm retrieval in nonobstructive azoospermia based on a panel of seminal exosomal mRNAs. This project intends to analyze the correlation between changes in spermatogenesis and exosomal mRNA expression in NOA model mice on the basis of the fact that the four biomarkers are closely related to human testicular spermatogenesis. This project also intends to use techniques, such as isolation of exosomes, generation and amplification of cDNA templates from long RNA in exosomes and Polymerase Chain Reaction assay, to further verify the accuracy and stability of the prediction model in the internal test set and independent validation set. Finally, a NOA preoperative decision-tree will be constructed. This project will provide a new method for noninvasive and precise prediction of the outcome of sperm retrieval in nonobstructive azoospermia before testicular sperm extraction.