Nerves in human epiphyseal uncalcified cartilage

Increasing evidence demonstrates clinical and neuroendocrine regulation of the skeletal system. We have demonstrated nerve fibers in cartilage canals in human fetal epiphyseal uncalcified cartilage. We investigated specimens from the femur, the proximal tibia, and the humerus from 12 human bodies with an age from the 22nd gestational week to 13 months after birth. We performed Bodian silver staining, Kluver-Barrera staining, and immunostaining for neurofilaments, myelin basic protein, S-100 protein, and vimentin. We observed positive Bodian staining and immunoreaction to neurofilaments in all specimens older than the 30th week of gestational age. Myelin or Schwann cells could not be demonstrated, nor could mechanoreceptors. This indicates a traditional classification as type C nerve fibers with sensory or sympathetic function. In skeletal nerves, an increasing number of neuropeptides influencing bone cells has been detected. The nerves in the cartilage canals may have functions such as regulation of developmental or pathological processes.