研究表明，B7-H3在睾丸、附睾、精囊及前列腺中均高表达，但其是否影响精子的发生、成熟和功能目前尚无报道。我们前期研究发现，特发性少、弱、畸精症患者精浆中B7-H3水平显著低于健康志愿者，且该分子可以诱导细胞分化、促进精子活力、促进细胞间粘附。据此我们推测B7-H3可能参与了精子的发生和成熟过程，其表达缺陷可能导致了特发性少、弱、畸精症的发生。鉴此，本项目拟通过ELISA检测、精子功能学实验、免疫组化、Western-blot、曲细精管及附睾内显微注射、RNA干扰、动物模型构建等手段，从临床、分子、细胞、组织和动物水平多层次研究以1）分析精浆B7-H3与精子质量之间的关系及临床意义；2）明确B7-H3对精子功能的影响；3）确定B7-H3在睾丸和附睾中的表达水平、分布情况及表达趋势；4）揭示B7-H3表达缺陷对精子发生、成熟和功能的影响。探索特发性少、弱、畸精症的发病机制，为治疗提供新思路。

The microenvironment around sperm is crucial for spermatogenesis, spermmaturation and its normal functions. Previous studies showed that B7-H3 is significantly highly expressed in testis, epididymis, seminal vesicles and prostate. However, the role of biology of B7-H3 on spermatogenesis and spermmaturation remains unknown. Our recent studies indicated that seminal B7-H3 levels in patients with idiopathic oligozoospermia, asthenozoospermia and teratozoospermia were significantly lower than that of healthy donors. Additionally, B7-H3 can induce cell differentiation, promote sperm motility and enhance cell adhesion. According to our findings and previous reports, we hypothesizes that B7-H3 plays a critical role in the spermatogenesis and spermmaturation, and its expression defect induces the pathogenesis of idiopathic oligozoospermia, asthenozoospermia and teratozoospermia. To test this hypothesis, ELISA, sperm function test, immunohistochemisty, Western-blot, microinjection into seminiferous tubules, RNAi were performed to investigate: 1) the association between seminal B7-H3 and sperm quality and its clinical significance; 2) the effect of B7-H3 on sperm functions; 3) the expression levels, distribution and trend in testis and epididymis; 4) the effect of expression defect of B7-H3 on spermatogenesis, spermmaturation and sperm functions. This project aims to analyze the effect and mechanism of B7-H3 expression defect on idiopathic oligozoospermia, asthenozoospermia and teratozoospermia, in order to provide new ways for future biological treatment.