Effects of co-administration of ghrelin agonist (GHRP-2) and GH on TNF-α, IL-6 and iNOS gene expression induced by LPS in the mouse brain

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.