Preparation Of Temperature - Sensitive Chitosan Hydrogel And Its Application In Sheep Experimental Study On Repair Of Articular Cartilage Defects

Articular cartilage plays important physiological role but has limited self-repair capacity. Until now, many methods have been developed to repair articular cartilage defects, but no one is perfect. Therefore, new methods were needed to be developed to get ideal results in repairing cartilage defects. Tissue-engineering is a new technique that brings new hopes for the functional and biological replacement of articular cartilage injuries.In recent years, the studies of hydrogel material show that the chitosan hydrogel biomaterial has nice histocompatibility and biodegradability, and is a hopeful scaffold material in cartilage tissue engineering. However, chitosan hydrogels were usually used as injectable cartilage scaffold. There is no report about its use in non injectable tissue engineering, which means, solidified before transplantation.In this paper, we studied this kind of possibility. First we prepared temperature-responsive chitosan hydrogel, and evaluated its characters of the toxicity and histocompatibility. Then, we constructed tissue engineered cartilage, with the prepared chitosan hydrogel and rabbit chondrocytes expanded in vitro. After that, the constructions were cultured in vitro and the survival and growth of the chondrocytes in the construction were observed and detected, the results confirmed that the chondrocytes survived well and produced matrix in constructions when cultured in vitro. Finally, we autologus transplanted the chitosan hydrogels-chondrocytes construction to the sheep's articular cartilage injuries. the transplantation of single chitosan hydrogels and injuries without treatments were servied as control groups. After 12 weeks and 24 weeks of transplantation, the orbicular articulars were taken out for detection. The results show that at 12 weeks, the articular cartilage defects of the experimental group have been restored obviously, at 24 weeks, the newborn cartilage is similar to its natural neighbor. However, the single chitosan hydrogels tansplantation group only has a partly repairment at 12 weeks, and has obvious repairment at 24 weeks, but still incomplete. In the group of no treatments, only the circumjacent of defects has newborn tissues. To sum up, the chitosan hydrogels is a good scaffold of cartilage tissue engineering and have good capability to repair the articular defects. The contents are divided into three parts as follows:1. Preparation of temperature-responsive chitosan hydrogel, and evaluation of its biological characters.2. Construction and detection of tissue engineered cartilage in vitro.3. Autologus transplantation of chitosan hydrogel-chondrocytes in vivo to repair cartilage injuries.