The three-dimensional microvascular and collagen fibrillar arrangements around rat vibrissa hairs as revealed by scanning electron microscopy

Abstract

The three-dimensional microvascular and collagen fibrillar arrangements around the vibrissa hairs of adult Wistar rats were studied by scanning electron microscopy. Each hair root was surrounded by the sinus, which consisted of the superficial ring sinus and the deeper cavernous sinus. Many trabeculae existed in the cavernous sinus but not in the ring sinus. The hair root within the cavernous sinus was surrounded by a basket-like capillary network which was denser at its lower part. The capillary network surrounding the lower part of the hair root was supplied by the radical artery and drained into the radical vein, while that surrounding the upper part of the hair root was supplied by the subcapsular artery and drained into the subcapsular vein. On the inside of the ring sinus, only a few arterioles ascended along the hair root and gave rise to the capillaries which were located below the epidermis. Our findings indicate that the lower part of the vibrissa hair, which is the most important area for hair growth, receives a more abundant blood supply than the upper part and is protected from external forces by the cavernous sinus with its many trabeculae.