背景：Rabbit tendon stem cells were isolated from tendon tissue. A tendon is a cord-like or membranous dense connective tissue at both ends of the muscle belly, which is convenient for muscle attachment and fixation. The tendon of a muscle is attached to two or more different bones. The traction of the tendon can make the contraction of the muscle drive the movement of the different bones. Each piece of skeletal muscle is divided into two parts： muscle belly and tendon. The muscle belly is composed of muscle fibers. It is red and soft and has the ability to contract. The tendon is composed of dense connective tissue, and the color is milky white and harder, without contraction ability. Tendons attach skeletal muscles to bones. The tendons of the long muscles are mostly round cords, and the tendons of the platysma are broad, thin, and membranous, also called aponeurosis. The muscle belly here is the so-called red muscle, and the tendon is the white muscle, which respectively control muscle strength, explosive power and endurance. Tendon stem cells （TSCs） are mesenchymal stem cells derived from tendon tissue. They have multi-directional differentiation potential and abnormally differentiate under the action of exogenous prostaglandin E2. When cultured in vitro, the cell population has the common characteristics of stem cells such as clonal formation, self-renewal and multi-differentiation potential. Tendon stem cells can be induced to differentiate into adipocytes, chondrocytes, and bone cells. In the nude mouse model, tendon stem cells can also form tendon-like tissues, cartilage-like tissues, and tendon-bone junction-like tissues. Compared with bone marrow mesenchymal stem cells, TSCs have better clonogenic ability and proliferation ability, higher expression of cartilage-related genes and tendon-related genes, and better osteogenic, adipogenic, and cartilage capabilities, so they can be used as seed cells in tissue engineering. The rabbit tendon stem cells produced by our company are prepared by the method of mixed digestion with collagenase and neutral protease and through the culture and selection of the special medium for tendon stem cells. The total amount of cells is about 5×10^5 cells/vial. The cells are identified by CD90/CD44 and CD34/CD45 immunofluorescence, and the purity is more than 90％ without HIV-1, HBV, HCV, mycoplasma, bacteria, yeast, and fungi.
