Prostaglandin E1 analog inhibits the microglia function: suppression of lipopolysaccharide-induced nitric oxide and TNF-alpha release.

Abstract

Release of nitric oxide and TNF-alpha, a toxic cytokine, have been reported to accelerate neuronal damage under several pathological conditions, such as trauma or ischemia in the central nervous system. In the present study, we tested the effect of alprostadil alfadex, a prostaglandin E1 analog, on cultured microglia from the rat spinal cord. The cultured microglia were exposed to lipopolysaccharide (LPS) (100 ng/ml), an endotoxin, for 24 h, then the released nitric oxide and TNF-alpha in the culture media was analyzed. The released nitric oxide was detected by the Griess reaction and released TNF-alpha was measured using ELISA method. The LPS-induced nitric oxide release was inhibited by the simultaneous addition of alprostadil alfadex in a dose-dependent manner (0.1-100 microM). The LPS-induced TNF-alpha release was also inhibited by alprostadil alfadex addition (0.1-100 microM). The IC50 values of alprostadil alfadex on nitric oxide and TNF-alpha release were about 1 and 10 microM, respectively. These results suggest that prostaglandin E1 possibly protects spinal cord neurons from several types of neurodegenerative damage, not only via increased blood supply, but also via inhibition of pathological immunoreactions of activated microglia.