Chitosan-hyaluronic acid hydrogel for cartilage repair
Authors: Prabha Nair
Neethu Mohan
A Sabareeswaran
P V Mohanan
Journal: International Journal of Biological Macromolecules (2017)
Discipline: BIOLOGY & BIOCHEMISTRY
Keywords: Cartilage regeneration; Chitosan; Chondrocyte encapsulated gels; Hyaluronic acid dialdehyde; Hydrogels
Affiliations: Division of Tissue Engineering & Regeneration Technologies, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences & Technology, 695012, India., Division of Toxicology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences & Technology, 695012, India., Division of Histopathology, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences & Technology, 695012, India., Division of Tissue Engineering & Regeneration Technologies, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences & Technology, 695012, India. Electronic address: .

Abstract:  The current study investigates the potential of chitosan-hyaluronic acid dialdehyde hydrogels for in vivo cartilage regeneration following two different approaches: Gel alone for cartilage regeneration or combination of chondrocytes and gel for cartilage repair. Critical size osteochondral defects were created in knee joints of Newzealand White rabbits. Allogenic rabbit chondrocytes were encapsulated in hydrogels and gel or gel+cells were implanted in defects aseptically. The regenerated cartilage was analyzed after 12 weeks of implantation. The morphological scoring indicates that repair tissue was formed in all the animals by 12 weeks irrespective of whether they were sham, received gel, or gel with cells as implant. However the repair tissue formed in sham appeared fibrous and opaque, where as those that received gel had texture similar to the surrounding native cartilage and animals with gel+cells showed varied response. Histology staining, score distribution and immunostaining for collagen Type II showed animals that received gel alone as the implant had a mixture of hyaline and fibro cartilage. The animals with cell encapsulated gels had more fibrous cells with weak staining for collagen type II. There was no significant enhancement in the quality of regenerated cartilage in presence of encapsulated chondrocytes. 

Retracted: No

PubPeer comments:
 The images Figure 1 b and c are having striking similarities in the background.  **b - Chitosan-hyaluronic acid dialdehyde gel implanted at the defect site (Gel alone group) c- Chitosan-hyaluronic acid dialdehyde gel encapsulated with allogenic chondrocytes implanted at the defect site (Gel + cells group) ** , 
 These photographs are gross pictures of the knee joint taken at the time of implantation. We have performed implantation in 6 animals in each of the gel alone and gel+ cells group. The gross images of the gels and gel with cells looks the same, and cannot be distinguished. The cells can be visible only under the microscope. However, as pointed out the photographs look similar and this must be an error that went unnoticed from our side at the time of submission. We will recheck our files and submit an erratum to the journal. The results of the study are based on the performance of retrieved implants and therefore the error pointed out in the figure1 is not expected to impact the results of the total study. , 
 My co-author and First author of the study - Dr Neethu Mohan has given an adequate comment to the image as pointed out by PuB peer. I agree with her comments above and we would do the needful for correcting the figure ,