Testicular Torsion Alters the Presence of Specific Proteins in the Mouse Testis as Well as the Phosphorylation Status of Specific Proteins

Abstract

Testicular torsion followed by torsion repair induces an ischemia-reperfusion injury to the testis that can render the testis aspermatogenic. Previous results have demonstrated this loss of spermatogenesis to be the result of germ cell apoptosis induced by oxidative stress. The present work reports protein changes occurring in the mouse testis 24 hours after repair of a testicular torsion known to induce germ cell apoptosis and severe seminiferous impairment. Total proteins were extracted from sham-operated testes and testes having had 2-hour 720Њ torsion 24 hours previously. Testicular proteins were separated by 2-dimensional electrophoresis and the resulting gel images were analyzed with image analysis software. Of the over 1100 proteins detected on the average gel, over 700 were consistently appearing in multiple gels, and those protein spot intensities were averaged within sham and torsion groups and compared between the 2 groups. Twenty-three proteins were consistently increased after torsion repair and 48 were decreased. Six proteins, 3 of which increased and 3 of which decreased after torsion repair, were identified by mass spectrometry. The 3 proteins that increased after torsion repair, ␤2-tubulin and 2 isoforms of serum albumin, as well as the 3 proteins that decreased after torsion repair, vimentin, phosphoglycerate kinase, and t-complex protein 1␤, were for the most part associated with various aspects of cell stress responses. The number of proteins phosphorylated on tyrosine residues exceeded the number of proteins phosphorylated on serine/threonine residues, but among 6 stress-related proteins specifically examined for phosphorylation in sham testes and those examined after torsion repair, increases in threonine phosphorylation of c-Jun NH 2 terminal kinase and activating transcription factor 2 were the most prominent. Knowing these proteins and the pathways to which they point will aid in the search for new therapies of oxidative stress in the testis.

Testicular Torsion-Detorsion- Histological and Biochemical Changes in Rat Testis

“…the decline in the testicular membrane constituents, protein and phospholipid, content in the present study lend support to this contention. The cholesterol content, however, was raised, perhaps due to the accumulation in the face of reported decline in testicular androgen production suggesting I/R stress might play a role in Leydig cell dysfunction, as well as by acting directly in germ cell apoptosis [23]. Similar observations have been reported in the literature in higher period of torsion earlier.…”

“…The formation of multinucleated cells, constituted by young spermatids have been shown in another study [22], similar observations in rats using D-thio-glucose were reported earlier [23]. This is a compound that interferes with glucose metabolism [24].…”

“…Unilateral testicular torsion is a pathological process that affects stages VI-XI of cycle of the seminiferous epithelium (CSE) in the contralateral non-twisted testis in torsion/detorsion and torsion/ orchiectomy states. These, coincidentally, are the stages that express low SOD levels [22][23][24][25]. Moreover, post-ischemic reperfusion, conditions that lead to selective death of germ cells in vivo, caused the very long chain poly unsaturated fatty acids (VLCPUFA) to disappear from the testicular sphingomyelin and cerebrosides of adult fertile rats, showing that these lipids are specific traits of spermatogenic cells [26,27].…”

Activation of Akt/Protein Kinase B and Extracellular Signal-regulated Kinase in Rats with Acute Experimental Testicular Torsion

“…These two pro-inflammatory factors are secreted from reperfusing leukocytes, including neutrophils [18] and hematogenous macrophages, which infiltrate into the interstitial spaces surrounding damaged tubules [23][24][25]. Nevertheless, other testicular cells, including Sertoli and Leydig cells, do not undergo apoptosis after I/R injury, although I/R-affected Leydig cells transiently cease steroid hormone secretion [2,32]. Several studies have reported expression and activation of pro-apoptotic signal molecules in experimental testicular I/R [14,19], but the role of intracellular signaling in the survival of testicular cells after I/R is poorly understood.…”

“…The Akt/protein kinase B (PKB) and extracellular signal-regulated kinase (ERK) 1/2 pathways mediate various growth factor-stimulated processes, such as cell division, growth, differentiation, and survival, in testicular cells [10,13,16,21,31,32]. Akt/PKB and ERK1/2 signaling, the most thoroughly investigated survival signals thus far, are involved in in vitro and/or in vivo cell survival after I/R injury in the brain [27], kidney [15,29], and heart [11,22].…”