Doxycycline Loaded Collagen-Chitosan Composite Scaffold for the Accelerated Healing of Diabetic Wounds

Summary

The prepared DOX-CL scaffold satisfied the prerequisites of an ideal DW dressing in mechanical strength, porosity, water absorption, degradation rate, sustained release, anti-bacterial, biocompatibility, and anti-inflammatory properties, which are considered to be essential for the recovery of damaged tissue in DWs.

Abstract

One major complication of diabetes mellitus is diabetic wounds (DW). The prolonged phase of inflammation in diabetes obstructs the further stages of an injury leading to delayed wound healing. We selected doxycycline (DOX), as a potential drug of choice, due to its anti-bacterial properties along with its reported anti-inflammatory properties. The current study aims to formulate DOX loaded collagen-chitosan non-crosslinked (NCL) & crosslinked (CL) scaffolds and evaluate their healing ability in diabetic conditions. The characterization result of scaffolds reveals that the DOX-CL scaffold holds ideal porosity, a low swelling & degradation rate, and a sustained release of DOX compared to the DOX-NCL scaffold. The in vitro studies reveal that the DOX-CL scaffold was biocompatible and enhanced cell growth compared with CL scaffold treated and control groups. The anti-bacterial studies have shown that the DOX-CL scaffold was more effective than the CL scaffold against the most common bacteria found in DW. Using the streptozotocin and high-fat diet-induced DW model, a significantly (p≤0.05) faster rate of wound contraction in the DOX-CL scaffold treated group was observed compared to those in CL scaffold treated and control groups. The use of the DOX-CL scaffold can prove to be a promising approach for local treatment for DWs.

Introduction

Diabetes mellitus (DM) is a condition where the body's failure to deliver insulin or react to its outcomes in abnormal digestion of straightforward sugars brings about an upsurge of blood glucose ¹. The most consecutive and crushing entanglement of DM is the diabetic wound (DW). Roughly 25% of patients with DM have the opportunity to build up a DW in their lifetime ¹. The hindered healing of DW is accredited to a triopathy of DM: immunopathy, vasculopathy, and neuropathy. Whenever DW is left untreated, it may result in gangrene development, therefore prompting the removal of the concerned organ ²

Protocol

All the animal procedures performed were approved by the institutional animal ethical committee of JSS College of Pharmacy, Ooty, India.

1. Preparation of DOX loaded porous scaffolds by freeze-drying method

1. Add 1.2 g of COL to 100 mL of water (e.g., Millipore) and keep aside for swelling.
2. Stir the swollen COL dispersion at 2000 rpm overnight to ensure complete dissolution of COL.
3. Prepare CS solution by dissolving approximately 0.8 g of CS in 100 mL of 1% acetic acid.
4. Stir the CS solution overnight at 2000 rpm to ensure uniform dispersion.
5. Mix DOX (1% w/v), followed by CS solution, to the C....

Results

Characterization of the DOX loaded NCL and CL scaffold
On visual examination, the NCL and CL scaffold was found to be cream in color. Besides, both the scaffolds appear to be like a sponge, stiff and inelastic when examined physically. SEM images of the NCL and CL scaffolds are shown in Figure 1. From the figure, it was clear that there was a decrease in pore size after crosslinking by forming intermolecular linkages. Also, the NCL and CL scaffolds porosity were found to.......

Discussion

The main objective of this study was to determine the effect of DOX loaded COL-CS scaffold on DW healing in rats. CL and NCL were prepared and evaluated in terms of morphology, swelling index, in vitro release kinetics, and biocompatibility.

Characterization of the DOX loaded NCL and CL scaffold
The prepared scaffolds were found to be porous with interconnected pores. These interconnected pores assure the porous, spongy nature that helps in the proper diffusion of oxygen.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
1-ethyl-(3-3-dimethyl aminopropyl) carbodiimide hydrochloride (EDC)	Merck Millipore, Mumbai, India	E7750
2-(N-morpholino) ethane sulfonic acid (MES)	Merck Millipore, Mumbai, India	137074
3-(4, 5 dimethyl thiazole-2 yl) -2, 5-diphenyl tetrazolium bromide (MTT)	Thermo Fisher, Mumbai, India	M6494
Deep freezer verticle	Labline Instruments, Kochi, India
Dialysis sack	Merck Millipore, Mumbai, India	D6191-Avg. flat width 25 mm (1.0 in.), MWCO 12,000 Da
Doxycycline	Sigma chemicals Co. Ltd, Mumbai, India	D9891
Elisa kit	R&D Systems	RMP900
Escherichia coli (E. coli)	National Collection of Industrial Microorganisms, Pune, India	NCIM 2567
Ethanol	Merck Millipore, Mumbai, India	100983
Lyophilizer-SZ042	Sub-Zero lab instruments, Chennai, India
Mechanical Stirrer-RQ-122/D	Remi laboratory instruments, Mumbai, India
Medium molecular weight Chitosan	Sisco Research Laboratories Pvt. Ltd., Mumbai, India	18824
Microtome-RM2135	Leica, U.K
Mouse embryonic fibroblast cells (3T3-L1)	National Centre for Cell Sciences, Pune, India
Multiple plate reader -Inifinte M200 Pro	Tecan Instruments, Switzerland
N-hydroxy succinimide (NHS)	Sigma chemicals Co. Ltd, Mumbai, India	130672
Pseudomonas aeruginosa (P. aeruginosa)	National Collection of Industrial Microorganisms, Pune, India	NCIM 2036
Scanning Electron Microscopy (SEM)-S-4800	Hitachi, India
Sodium hydroxide (NaOH) pellets	Qualigen fine chemicals, Mumbai, India	Q27815
Staphylococcus aureus (S. aureus)	National Collection of Industrial Microorganisms, Pune, India	NCIM 5022
Staphylococcus epidermis (S. epidermis)	National Collection of Industrial Microorganisms, Pune, India	NCIM 5270
Streptozotocin (STZ)	Sisco Research Laboratories Pvt. Ltd., Mumbai, India	14653
Type-1 rat Collagen	Sigma chemicals Co. Ltd, Mumbai, India	C7661
Ultraviolet–visible spectroscopy-1700	Shimadzu