This research aimed to study the anti-inflammatory and immunomodulatory effects of guluronic acid (G2013) on gene expression of TLR4, MyD88, SHIP1, SOCS1, NF-κB, and assessment of the level of IL-1β as a pro-inflammatory cytokine in HEK-Blue hTLR4 cell line.

The cytotoxicity of G2013 was assessed by the MTT assay. The mRNA expression levels of the mentioned genes were measured by qRT-PCR. IL-1β concentration in culture media was determined using ELISA method.

MTT assay demonstrated that G2013 (before the concentration of 125 μg/ml) had no cytotoxic effect on HEK-Blue hTLR4 cells. Our results indicated that the low and high doses of this drug could significantly reduce the gene expression of TLR4 and MyD88, as compared to the control group (p < 0.05). Moreover, it was found that the low dose of this drug could significantly increase the gene expression of SHIP1 and SOCS1, as compared to the control group (p < 0.05). Furthermore, the study findings revealed that the level of NF-κB gene expression significantly reduced, in both doses of G2013 compared to the control group (p < 0.05, p < 0.01, respectively). Our data showed that the level of IL-1β in culture media decreased by both doses of this drug in comparison to control group (p < 0.05).

This study indicates that G2013 is able to induce SHIP1, SOCS1 and reduce TLR4, MyD88, NF-κB at the level of gene expression and decrease IL-1β as a pro-inflammatory cytokine which might be recommended for reduction of inflammatory reactions.