1Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
2Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
3Department of Biology, Qom Branch, Islamic Azad University, Qom, Iran
4Rastegar Reference Laboratory, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
The aim of this study was to examine the anti-inflammatory effects of co-administration of growth hormone-releasing peptide-2 (GHRP-2) and growth hormone (GH) on tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) gene expression induced by LPS in the mouse brain. Thirty-five male NMRI mice (25±5 g) were injected through the mouse tail vein with saline, GHRP-2 (100 μg/kg), GH (25 μg/kg) or GHRP-2 + GH, 30 min before the intraperitoneal injection of LPS (5 mg/kg). Then, inflammation was induced by the intraperitoneal injection of LPS. The control animals received sterile saline in the first and second injections. Changes in the expression level of TNF-α, IL-6 and iNOS genes were studied in the mouse brain by a semi quantitative RT-PCR method. The results of this study showed that GHRP-2 or GH significantly decreased the expression of TNF-α and IL-6 genes in brain 2 h after the injection of LPS. Co-administration of GHRP-2 and GH markedly reduced the expression of TNF-α and IL-6 genes. LPS had no effect on the expression of iNOS gene in brain. The data suggest that co-administration of GHRP-2 and GH has a protective effect in brain inflammation induced by LPS through inhibition of TNF-α and IL-6.