Torregrosa Nuria, Domínguez-Fandos David, Camejo Maria Isabel, Shirley Cynthia R, Meistrich Marvin L, Ballescà José Luis, Oliva Rafael
Human Genetics Research Group, IDIBAPS, University of Barcelona, Barcelona, Spain.
Hum Reprod. 2006 Aug;21(8):2084-9. doi: 10.1093/humrep/del114. Epub 2006 Apr 21.
The protamine 1-to-protamine 2 ratio (P1/P2) is altered in the sperm cells of some infertile patients. Also, evidence for increased protamine 2 precursors (pre-P2) in a few patients has been reported. But so far, there have been no studies measuring simultaneously these two variables in a large number of patients.
We measured the P1/P2 ratio and the presence of pre-P2 using, for the first time, an antibody specific to the precursor pre-P2, together with other sperm parameters in 224 infertile patients. Additionally, the DNA integrity was assessed by terminal transferase dUTP nick-end labelling (TUNEL) in a subset of the samples.
Pre-P2 levels show a significant positive correlation with the P1/P2 ratio, with the presence of other proteins and, at low pre-P2 levels, with TUNEL-positive sperm. An inverse correlation with sperm count, normal morphology and motility was detected.
The levels of pre-P2 may provide clues into the pathogenic mechanisms of infertility. The increased proportion of pre-P2 in some patients with increased P1/P2 ratio suggests an involvement of pre-P2 processing. The positive correlation between TUNEL-positive sperm and pre-P2 at low pre-P2/P2 ratios also suggests a link between deficient protamine processing and decreased DNA integrity.
在一些不育患者的精子细胞中，鱼精蛋白1与鱼精蛋白2的比例（P1/P2）会发生改变。此外，有报道称少数患者的鱼精蛋白2前体（pre-P2）有所增加。但到目前为止，尚未有研究在大量患者中同时测量这两个变量。
我们首次使用针对前体pre-P2的特异性抗体，连同其他精子参数，测量了224例不育患者的P1/P2比例和pre-P2的存在情况。此外，通过末端脱氧核苷酸转移酶dUTP缺口末端标记法（TUNEL）对部分样本的DNA完整性进行了评估。
Pre-P2水平与P1/P2比例、其他蛋白质的存在情况呈显著正相关，在低pre-P2水平时，与TUNEL阳性精子也呈正相关。检测到与精子计数、正常形态和活力呈负相关。
Pre-P2水平可能为不育的致病机制提供线索。在一些P1/P2比例升高的患者中，pre-P2比例增加表明pre-P2加工过程存在问题。在低pre-P2/P2比例时，TUNEL阳性精子与pre-P2之间的正相关也表明鱼精蛋白加工缺陷与DNA完整性降低之间存在联系。
