The book showed the existence of two different populations of hypertrophic chondrocytes in the growth cartilage of prenatal and postnatal horses, and they die by non-apoptotic modes of physiological death. An in vitro three-dimensional model for inducing hypertrophic chondrocytes to die by the same mechanisms seen in vivo has been established. The system produced in the current work has been used to study the gene expression differences between different populations of hypertrophic chondrocytes during their early and late stages.