The subject invention concerns a method of introducing at least one DNA sequence expressing a protein or protein fragment which substantially alleviates articular cartilage defects. This method involves in vitro culture of chondrocytes, transfection of the chondrocytes with a recombinant vector housing the DNA sequence to be expressed, and delivery of the transfected chondrocytes to the damaged cartilage region. This method can also be used in tandem with synovial cell delivery techniques of the present invention. This method is also useful as a model in animal studies regarding joint pathologies.