Compositions and methods are provided for modulating the growth, development and repair of cartilage, bone or other connective tissue. Devices and stimulus waveforms are provided to differentially modulate the behavior of chondrocytes, osteoblasts and other connective tissue cells to promote proliferation, differentiation, matrix formation or mineralization for in vitro or in vivo applications. Continuous-mode and pulse-burst-mode stimulation of cells with charge-balanced signals may be used. Cartilage, bone and other connective tissue growth is stimulated in part by nitric oxide release through electrical stimulation and may be modulated through co-administration of NO donors and NO synthase inhibitors. The methods and devices described are useful in promoting repair of bone fractures, cartilage and connective tissue repair as well as for engineering tissue for transplantation.