Adrenomedullin attenuates interleukin-1β-induced inflammation and apoptosis in rat Leydig cells via inhibition of NF-κB signaling pathway

The aim of this paper is to investigate the protective effects of adrenomedullin (ADM) on interleukin-lf3 (IL-1 beta)-induced inflammation and apoptosis in rat Leydig cells and its underlying molecular mechanisms. Leydig cells were isolated from adult Sprague-Dawley rats. The cell culture was established by adding ADM 2 h prior to 24 h treatment with IL-1 beta-induced cytotoxicity. We detected cell viability and concentrations of testosterone, reactive oxygen species (ROS), malondialdehyde (MDA), and reduced glutathione (GSH). Gene expression levels were measured for inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2). Concentrations were detected for nitric oxide (NO) and prostaglandin E2 (PGE2). Apoptosis was assessed using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Levels of gene expression and protein were detected for BcI-2, Bax, caspase-3, and poly adenosine diphosphate-ribose polymerase (PARP). Protein levels were measured for nuclear factor kappa B (NF-kappa B) p65 and linoc. ADM reduced IL-1 I3-induced cytotoxicity. ADM pretreatment significantly increased testosterone concentrations and decreased ROS, MDA, and GSH concentrations. ADM pretreatment inhibited IL-1 beta-induced inflammation in Leydig cells by decreasing the gene expression levels of iNOS and COX-2, as well as the concentrations of NO and PGE2. ADM pretreatment further decreased the number of TUNEL-positive stained Leydig cells, as confirmed by the increase in gene expression and protein levels of Bc1-2 and the decrease of Bax, caspase-3, and PARP levels. Moreover, ADM pretreatment inhibited NF-KB p65 phosphorylation and hcBcc phosphorylation and degradation. ADM has potential anti-inflammatory and anti-apoptotic properties in IL-1 beta-induced rat Leydig cells, which might be related to NF--KB signaling pathway. (C) 2015 Elsevier Inc. All rights reserved.