[#1996-02] Effect of beta-glucans on the nitric oxide synthesis by peritoneal macrophage in mice, N. Ohno et al.

Effect of beta-glucans on the nitric oxide synthesis by peritoneal macrophage in mice

Ohno N, Egawa Y, Hashimoto T, Adachi Y, Yadomae T.

School of Pharmacy, Tokyo University Pharmacy and Life Science, Japan.

Nitric oxide (NO) is an important effector molecule on antimicrobial and antitumor effects of macrophages. (1 -> 3)-β-D-Glucan (β-glucan) is well known to show various immunopharmacological effects such as antimicrobial effect and antitumor effect by activating various points of host defense mechanisms. This paper deals with NO synthetic activity of peritoneal macrophage (PM) induced by β-glucan administration in mice. The activity was determined by measuring NO concentration in PM culture by Griess reagent after 24 or 48 h in vitro culture. Administration (i.p. or i.v.) of a branched soluble (1 -> 3)- β-D-glucan, grifolan (GRN), from Grifola frondosa ( maitake ) enhanced NO synthesis of PM dose and time dependently. The activity was abrogated by the addition of N(G)-monomethyl-L-arginine (L-NMMA) in vitro. The most significant activity was observed at 3-7 d after the administration of GRN (250 μg/mouse). PM from all strains of ICR, C3H/HeN, C3H/HeJ, BALB/c, BALB/c nu/nu, C57BL, and AKR mice showed significant activity by GRN administration. Among β-glucans tested, SSG and OL-2, highly branched soluble glucans, and a particulate β-glucan, zymosan, showed similar activity. Addition of GRN directly to in vitro RAW 264.7 or proteose peptone induced peritoneal macrophage (PP-PEC) culture could not enhance NO synthesis. However, NO synthesis of PP-PEC was enhanced in vitro by addition of GRN in the presence of interferon γ (IFNγ). Gene expression of IFNγ mRNA in the liver and PEC were enhanced in GRN administered mice assessed by reverse transcriptase assisted PCR (RT-PCR) method. These facts strongly suggested that β-glucan has capacity to enhance NO synthesis of PM in vivo through IFNγ mediated mechanism.