The albino rat with rupture of kneecap tendon in the rear leg can restore its normal motor function by transplantation of tendon, which was differentiated from embryonic stem (ES) cells step by step. The research production by Professor Hongwei Ouyang's group, College of Medicine, Zhejiang University, provide a feasible way to put the theory of ES cell therapy for injured soft tissue such as tendon into application. The relevant thesis was published in STEM CELL, the prestigious journal with the highest Impact Factor (IF) in the field of stem cell. It was the first paper concerning the tendon of the reparative regeneration by ES cells in the world and the reviewers of the journal considered the research as pioneering work.

Professor Ouyang's group placed 10~20 ES cell blocks on the processed culture plate for low-density culture and then collected the mesenchymal stem cells for further cloning cell sieve, gene amplification, qualitative research. After two weeks' soak in the special culture solution, these differentiated mesenchymal stem cells turned into membranaceous mesenchymal stem cell patches which could be rolled into tendon-shaped tissue. The stem cell patches differentiated into tendon cells to work properly by a series of continual stimulations such as traction or extrusion.
There are more and more connective tissue damage, nearly 50% of the sport injury, in the joints like shoulder, knee, elbow, and etc. Authoritative data makes clear that there are at least millions of tendon injuries in two hundred million people every year. Currently the therapies for tendon injury include physiotherapy and suture, which have limited curative effect. Besides, tendons cannot be completely regenerated, so the repaired tendon tissue is always fragile. In a word, the patients have to suffer the pain in the rest of their life. To the athlete it means the end of his career. The development of tissue engineering technique and stem cell technology brings the new hope to the improvement of tendon reparation.

According to the report of the University of Pennsylvania, the embryonic tendon cell can be completely regenerated, while the adult tendon cell cannot. The ES cell, which Professor Hongwei Ouyang called 'the queen of reinvention', can be differentiated into all kinds of tissues and organs because of its totipotency, so it is the optimal embryonic regenerative cell material. People haven't transplanted the ES cells cultured in vitro to repair the injured tissue until FDA of the USA  conferred clearance on Geron company to begin world's first human clinical trial of ES cell-based therapy for nervous tissue lesions in 2009, since they didn't find a proper way to control the differentiation. Professor Hongwei Ouyang took a new measure of step induction culture to reduce the risk of incomplete differentiated ES cell's canceration dramatically. All of the test albino rats didn't have cancer; on the contrary the quality of regenerative tendons was greatly improved. The judges of the journal considered that the research product provided clinical application of ES cell-based connective tissue regeneration with experimental data and a new method.

Professor Ouyang has long been engaged in the research of cell-transplanted tissue regeneration technology. He had once successfully extracted mesenchymal stem cell from marrow for culture in vitro; this time he cultured ES cell in vitro for transplantation. He said, both growing ability and biological nature of the ES cell are better than the ones of the mesenchymal stem cell. What's more, the ES cell is suitable for batch production and has a promising perspective. Furthermore Professor Ouyang's group invented natural-silk tendon steadier and took out the national patent. The research product was published in Biomaterials, the journal with the highest IF in the field of biomaterial. His group became one of the handful domestic research groups that published papers in both of the key fields' journals with the highest IF in regenerative medicine.

ES cell, the initial stage of body development, is regarded as the best material for body reparation. American President Obama's first technology policy is to support the ES cell research and he thinks that it will influence American strategic priority in the future. The ES cell industry is considered as the next strategic industry following the IT industry by Mr Li Jiacheng and Osiri stem cell company, USA, is considered as the next Microsoft. The adult stem cell is put into clinical application at the present time. In addition, ES cell will gradually be used in clinical therapy with the refining of the stem cell technology. It's sure that the application of ES cell will accelerate the development of the clinical medicine greatly.