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Expression of cAMP-responsive element modulator (CREM) in rat testes following chronic cocaine administration
Haikun Li1, Joseph C Dunbar, C B Dhabuwala
1Department of Urology, Wayne State University, School of Medicine, Detroit, Michigan, USA. hli@med.wayne.edu
Objective:
c-AMP-responsive element modulator (CREM), one of the nuclear factors involved in the regulation of gene expression by cAMP, has an important role in spermatogenesis. Our recent study has shown that chronic administration of cocaine to male rats results in disruption of spermatogenesis, including reduction of germ cells. As a further step toward understanding this process, we have studied the role of CREM in cocaine-induced testicular damage.
Materials And Methods:
Sprague-Dawley rats were administered cocaine hydrochloride subcutaneously daily for 90 days. Control animals received equal volumes of normal saline daily for 90 days. Testes were removed after 15, 30, 90 days of cocaine administration. Total RNA was extracted from the testes and subjected to RT-PCR. Testicular tissue was also homogenized in a lysis buffer, and Western blotting was performed using anti-CREM antibody.
Results:
RT-PCR analysis detected a single fragment of approximately 520 base pairs (bp) in control testes at all time points. The cocaine-treated testes showed reduced expression of CREM fragment. Western blot analysis using CREM antibodies confirmed the RNA data. There were reduced CREM proteins in the cocaine-treated testes compared with controls.
Conclusions:
The CREM gene is essential for spermatogenesis. Our results indicate that the reduction in testicular CREM expression may be one of the mechanisms responsible for disruption or impairment of spermatogenesis in the testes following chronic cocaine administration.