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)-beta-D-Glucan
(beta-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 beta-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)-beta-D-glucan, grifolan
(GRN), from Grifola frondosa 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 mu
g/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 beta-glucans tested,
SSG and OL-2, highly branched soluble glucans,
and a particulate beta-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
gamma (IFN gamma). Gene expression of IFN
gamma 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 beta-glucan has capacity to enhance NO synthesis of
PM in vivo through IFN gamma mediated mechanism.
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