The Stapedial Artery in the Mongolian Gerbil ( Meriones unguiculatus )

Head arteries of the red squirrel (Sciurus vulgaris)

The red squirrel (Sciurus vulgaris) is a medium-sized rodent protected in most of Europe. The present study aimed to investigate and describe the arterial vascularization of the head of the adult red squirrel. In the study, 48 specimens of adult red squirrels were used. The first preparation method used in the study was corrosion casting using a stained solution of the chemo-setting acrylic material injected into bilateral common carotid arteries resulting in corrosion castings of the vessels on a bone scaffold. The second method was injecting liquid-stained latex into both common carotid arteries. It resulted in a stained arterial vessel on fixed soft tissue preparations. The main vessels providing blood to the head were paired with common carotid arteries that divide into external and internal carotid arteries. The internal carotid artery passes into the stapedial artery. After giving its branches, the stapedial artery exits the cranial cavity through the sphenofrontal foramen and enters the orbit. The suborbital and the mandibular regions were supplied by the maxillary artery, linguofacial trunk, and their branches. Description of the detailed anatomy of the head arteries in red squirrels may contribute to establishing diagnostic and treatment protocols for wildlife rehabilitation centers, which may be crucial since red squirrels are endangered by the spreading of invasive Eastern gray squirrels (Sciurus carolinensis) in Europe. It may also contribute to veterinary care for other members of the Sciuridae family kept as pets.

Applicability of vital staining and tissue clearing to vascular anatomy and melanocytes' evaluation of temporal bone in six laboratory species

The purpose of the present study was to define the applicability of tissue clearing to the field of otology. We combined tissue clearing with vital staining perfusion via a pumping system to examine the vascular anatomy of temporal bones in laboratory animals. We used six different types of species including Korean wild mouse, mouse, Mongolian gerbil, hamsters and Guinea pigs. A mixture of Alcian blue reagent and 4% paraformaldehyde was circulated throughout the entire circulatory system of the animal via a perfusion pump system. Transparency images were obtained from the temporal bones according to the protocol of the SunHyun 3D Imaging Kit. In examining the inner surface of the tympanic membrane, flaccid part (pars flaccida) was positioned along the entire marginal area in Guinea pig. In the Guinea pig, unlike the other species, the cortical bone of the mastoid (bullae) was easily removed using cold instruments, allowing a direct approach to the enclosed structures. The distribution and pattern of cochlea melanocytes were compared among the species. "Mobius strip"-like accumulated melanocytes in vestibules were shown in both the Korean wild mouse and mouse. The collateral blood supply to the cochlea in six different species was checked in various pattern. Combining dye infusion with tissue-clearing techniques, we documented the middle ear and transparent inner ear structures in six different species. The information and associated images will help other researchers to develop hypotheses and design experimental investigations.