Shotgun proteomics analysis of protein responding to drug addition in rat testis.

Abstract

Drug addiction is one of the major problems in the world that affects human health in various systems, including potentially affecting the male reproductive system. The most common of drug abuses are methamphetamine (METH) and dextromethorphan (DXM). Previously, METH can induce apoptotic cells within the seminiferous tubule and reduce testosterone that affect to spermatogenesis. Moreover, both chemicals reduced gonadotropin releasing hormone (GnRH) in the hypothalamus, affecting spermatogenesis, and causing poor sperm quality in the testis. Diazepam is a common drug used to treat the symptoms of drug addiction. However, diazepam causes adverse effects on germ cells in male reproductive system. Interestingly, pre-germinated brown rice (PGBR); a high GABA natural substance, can reduce the effects of drug addiction. As mentioned above, drug addiction and its treatments can affect on several cell signaling cascades that can induce changes in several proteins. These findings provide the hypothesis that drug addiction and treatments might be associate with changes of proteins in the testis. Therefore, the aim of this study is to investigate changes of protein profiles in rat testis in drug addiction and its treatments using proteomics analysis. Male Sprague-Dawley rats were divided in to 2 groups of addiction model. METH model, those rats in a control group were received normal saline for 15 days, whereas those rats in an ED-binge METH group were received an escalating dose of METH for 14 days following a binge dose of METH on day 15. DEX model, the control group, those rats were received normal saline for 15 days and treated with distilled water for 60 days. In the DXM, those rats were received 30 mg/kg DXM. Withdrawal group, those rats were received DXM and distilled water for drug-withdrawal. Diazepam group, those rats were received DXM and treated with 10 mg/kg diazepam. Synthetic GABA group, those rats were received DXM and treated with 0.8 mg/kg synthetic GABA. Pre-germinated brown rice group, those rats were received DXM and treated with 5 mg/kg PGBR. After the end of treatments, animals were sacrificed and the testis was collected. Proteins were extracted from the rat testis, which were pooled from three samples in each group. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed to identify the protein profiles. Moreover, expression of calbindin in rat sperm after treated with METH-addiction was examined using immunohistochemistry. The protein expression profiles after drug addiction and treatments are enriched in calcium-binding protein pathways and ATP binding, which play critical roles in calcium homeostasis, cell functions in the testis and sperm function. The present study showed that alteration of the protein profile after drug addiction, which is associated with the calcium signaling pathway, causes disrupted intracellular Ca2+ homeostasis in the testis and might be related to spermatogenesis deficiency, resulting in the reduction of sperm quality. In addition, alteration of the protein profile in diazepam treatment indicated an adverse effect, while GABA and PGBR treatments showed a recovery effect on the testis via intracellular Ca2+ signal. These findings examined the effects of drug addiction and addiction treatments on spermatogenesis and sperm quality through Ca2+homeostasis.

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