Effect Of Low Molecular Weight Chitosan Research Articles

Low-molecular weight chitosan enhances antibacterial effect of antibiotics and permeabilizes cytoplasmic membrane of Staphylococcus epidermidis biofilm cells.

This study evaluated the effect of low-molecular weight chitosan on Staphylococcus epidermidis, a common colonizer of joint implants and other prosthetic devices. We have also attempted to elucidate its mechanism of action. Chitosan was found to be effective against both the planktonic and biofilm cells (MIC80 35-40mg/L; MBIC80 40-150mg/L), in contrast to the antibiotics erythromycin and tetracycline with no antibiofilm activity (MBIC80 not found). In combination, chitosan had an additive effect with antibiotics on suspension growth of S. epidermidis (FICi 0.7-1.0), and the combinatory action caused a complete inhibition of biofilm metabolic activity in some cases. In addition, chitosan caused rapid cellular damage and enhanced antihaemolytic activity of tetracycline in combination towards S. epidermidis biofilm cells. Chitosan efficiently inhibited S. epidermidis growth acting via cell membrane damage, yet the extent of antimicrobial and antibiofilm activities was quite strain-specific. It was proved to be a very efficient antimicrobial agent worth further examination as a potent candidate in pharmaceutical research. Apart from antimicrobial activity, it also acted as antivirulence enhancing agent which is a very promising strategy for alternative infectious diseases treatment.

Effects of low-molecular-weight-chitosan on the adenine-induced chronic renal failure rats in vitro and in vivo

The effects of low-molecular-weight-chitosan (LMWC) on chronic renal failure (CRF) rats induced by adenine were investigated in vivo and in vitro. Chitosan were hydrolyzed using chitosanase at pH 6–7 and 37° for 24 h to obtain LMWC. In vitro, the effect of LMWC on the proliferation of renal tubular epithelial cells (RTEC) showed that it had no cytotoxic effect and could promote cell growth. For the in vivo experiment, chronic renal failure rats induced by adenine were randomly divided into control group, Niaoduqing group, and high-, medium- and low-dose LMWC groups. For each group, we detected serum creatinine (SCR), blood urea nitrogen (BUN), and total superoxide dismutase (T-SOD), glutathione oxidase (GSH-Px) activities of renal tissue, and obtained the ratio of kidney weight/body weight, pathological changes of kidney. The levels of serum SCR, BUN were higher in the adenine-induced rats than those in the control group, indicating that the rat chronic renal failure model worked successfully. The results after treatment showed that LMWC could reduce the SCR and BUN levels and enhance the activities/levels of T-SOD and GSH-PX in kidney compared to control group. Histopathological examination revealed that adenine-induced renal alterations were restored by LMWC at three tested dosages, especially at the low dosage of 100 mg kg−1 d−1.

Preparation and Properties of Nanochitosan

Chitosan was degraded into low-molecular-weight chitosan (LWCS) using different concentrations of H2O2. Then different concentrations of tripolyphosphate (TPP) were incorporated to make nanochitosan. The effects of LWCS on nanochitosan particle size and the zeta potential are discussed. The cross-linking was best when the LWCS/TPP mass ratio was approximately 5:2, at which nanochitosan particles formed and the zeta potential measured at this moment was minimal. A lower molecular weight corresponded to a smaller nanoparticle size.

Depolymerized products of chitosan as potent inhibitors of tumor-induced angiogenesis

Water-soluble low-molecular weight chitosan (LMWC) and chitooligosaccharides (COs) were obtained from chitosan (16% N-acetylation) by depolymerization induced by potassium persulfate under nitrogen atmosphere for 2 h. They were characterized by IR, X-ray, HPLC and (13)C-NMR. Splitting of C3/C5 signals in the latter indicated a newer conformation, and also showed prominence of acetyl groups in LMWC, may be due to cleavage between two consecutive deacetylated residues. Molecular weight of LMWC, determined by HPSEC, showed a single peak of approximately 37 kDa. HPLC analysis of the solvent-extracted fraction revealed COs enriched with pentamer, hexamer and higher oligomers. The effect of LMWC and COs on the growth of Ehrlich ascites tumor (EAT) cells and tumor-induced neovascularization was studied. COs (50 microg) were more effective compared to LMWC (100 microg) and proved to be potent angioinhibitory and antitumor compounds, as shown by inhibition of angiogenesis and inducing apoptosis as a function of DNA fragmentation.

The effect of low molecular weight chitosan on bone resorption in vitro and in vivo.

We studied the effect of low molecular weight chitosan (LMWC) on the formation of osteoclast-like multinucleated cells (OCLs) in the co-culture of mouse osteoblastic cells and bone marrow cells in the presence of 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3]. LMWC at 440 microg/ml inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive OCLs induced by 1alpha,25(OH)2D3. We prepared OCLs in the co-culture of osteoblastic cells and bone marrow cells. The effect of LMWC on pit formation by OCLs was examined using dentin slices, and LMWC inhibited pit formation at 440 microg/ml. Oral administration of the LMWC to ovariectomized rats prevented a decrease in bone mineral density (BMD) of the lumbar vertebra without affecting the body and uterus weights. These results suggested that LMWC prevented a decrease in BMD in vivo by inhibiting osteoclastic bone resorption.