Growth hormone improves immune function and survival in burned mice infected with herpes simplex virus type 1

Recombinant human growth hormone (rhGH) is often used clinically for the treatment of burned patients to promote wound healing and to improve protein metabolism. Recently, the immunomodulatory activity of GH has been described, but it remains unclear whether immune abnormalities associated with burn are improved by rhGH administration. To determine the immunoregulatory activities of rhGH in thermal injury, the survival of burned mice infected with herpes simplex virus type 1 (HSV-1), along with interferon-gamma (IFN-gamma) production by splenic mononuclear cells (SMNCs), and generation of cytostatic macrophages in burned mice were examined after exogenous administration of rhGH. Data showed that the mortality after HSV-1 infection was improved in burned mice treated with a 4-mg/kg dose of rhGH every other day for five doses. Also, the decreased IFN-gamma response of SMNCs from burned mice improved with rhGH therapy. Further, cytostatic macrophages were generated in burned mice treated with rhGH, whereas these macrophages were not demonstrated in burned mice treated with saline. These results indicate that rhGH can improve immune function in burned mice, specifically improving survival in HSV-1 infection, boltering IFN-gamma production by SMNCs, and increasing production of cytostatic macrophages.