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 growthhormone-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 mousebrain. 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 sterilesaline in the first and second injections. Changes in the expression level of TNF-α, IL-6 and iNOS geneswere studied in the mouse brain by a semi quantitative RT-PCR method. The results of this study showedthat GHRP-2 or GH significantly decreased the expression of TNF-α and IL-6 genes in brain 2 h after theinjection of LPS. Co-administration of GHRP-2 and GH markedly reduced the expression of TNF-α and IL-6genes. 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-αand IL-6.