Architecture of blood vessels in the mouse infraorbital nerve

Abstract

We examined the normal intraneural vascularisation of the infraorbital nerve from the infraorbital foramen to the peripheral vibrissae to know a normal intraneural vascularisation in a peripheral pure sensory nerve. Indian ink was injected into the heart of the mouse for observation of vascular architecture in the infraorbital nerve. Three-dimensional images of blood vessels in the infraorbital nerve were then reconstructed using 3D visualization software.Optical microscopic observation of the peripheral section of the normal mouse infraorbital nerve (near mouse vibrissae) revealed fascicles of nerve fibers (10-60 µm in diameter) covered with perineurium, with one blood vessel normally present within the fascicle. Optical microscopic observation of the cross-section of normal mouse infraorbital nerve near the infraorbital foramen revealed nerve fiber fascicles (about 150 µm in diameter) covered with epineurium extending from proximal to peripheral areas, increasing in number as they branched. In the nerve fascicle surrounded by the perineurium near the infraorbital foramen, a few blood vessels were distributed. As the nerve fascicle branched and extended, the blood vessels also branched, providing one blood vessel in each nerve fascicle. There were multiple blood vessels in between the epineurium and perineurium. The blood vessels in nerve fascicles consisted of thin branches communicating with blood vessels outside of the perineurium. Nerve fascicles were surrounded by networks of blood vessels communicating with capillaries, arteriolae and venulae. Some blood vessels showed chain-like distribution in nerve fascicles. In the peripheral part of the infraorbital nerve, the blood vessel in the nerve fascicle exited before the nerve entered a vibrissa. The blood vessel goes out of the nerve to this point that enters the vibrissa.