Anti-inflammatory effects in a mouse osteoarthritis model of a mixture of glucosamine and chitooligosaccharides produced by bi-enzyme single-step hydrolysis

Yali Li,Liang Chen,Yunxiang Liang,Yangyang Liu,Yong Zhang,Yuxia Mei

doi:10.1038/s41598-018-24050-6

Abstract

We developed a novel technique of bi-enzyme single-step hydrolysis, using recombinant chitosanase (McChoA) and exo-β-D-glucosaminidase (AorCsxA) constructed previously in our lab, to degrade chitosan. The hydrolysis product was shown by HPLC, FTIR, and chemical analyses to be a mixture (termed “GC”) composed primarily of glucosamine (80.00%) and chitooligosaccharides (9.80%). We performed experiments with a mouse osteoarthritis (OA) model to evaluate the anti-inflammatory effects of GC against OA. The three “GC groups” (which underwent knee joint damage followed by oral administration of GC at concentrations 40, 80, and 160 mg/kg·bw·d for 15 days) showed significantly downregulated serum expression of pre-inflammatory cytokines (IL-1β, IL-6, TNF-α), and significant, dose-dependent enhancement of anti-inflammatory cytokine IL-2, in comparison with Model group. Levels of C-reactive protein, which typically rise in response to inflammatory processes, were significantly lower in the GC groups than in Model group. Thymus index and levels of immunoglobulins (IgG, IgA, IgM) were higher in the GC groups. Knee joint swelling was relieved and typical OA symptoms were partially ameliorated in the GC-treated groups. Our findings indicate that GC has strong anti-inflammatory effects and potential as a therapeutic agent against OA and other inflammatory diseases.

Highlights

Chitin, the second most abundant carbohydrate polymer, is widespread in organisms, e.g., fungal cell walls, crustacean shells, insect exoskeletons, mollusk radulae and beaks, and fish scales
GlcN salts are generally produced by acid hydrolysis in industry, and a high degree of heterogeneity is considered to exist in industry-sponsored trials of GlcN salts[14]
Except for the mobile solvent peak, the high-performance liquid chromatography (HPLC) spectrum displayed a main peak at 6.027 min (Fig. 1B), identical to that of standard D-GlcN hydrochloride (Fig. 1A)

Summary

Introduction

The second most abundant carbohydrate polymer (after cellulose), is widespread in organisms, e.g., fungal cell walls, crustacean shells, insect exoskeletons, mollusk radulae and beaks, and fish scales. To improve the water solubility and bioavailability of chitosan, it is often degraded into chitooligosaccharides (ChOS) or glucosamine (GlcN) by chemical or enzymatic methods. A variety of bioactivities of ChOS and GlcN have been demonstrated, including antitumor[1], antimicrobial[2,3], immunomodulatory[4,5], antioxidant[6], and anti-inflammatory[7,8]. GlcN and ChOS can be used as SYSADOAs because of their anti-inflammatory effect, reducing the need for NSAIDs11,12. Administered GlcN has been used worldwide for effective OA therapy, typically in combination with chondroitin sulfate or other compounds. It could be deduced that a combination of free GlcN and ChOS (or chitosan) may be effective for OA treatment

Methods

Results

Conclusion