MORPHOLOGICAL AND TOPOGRAPHICAL PARTICULARITIES OF SOME LYMPH NODES FOR HOUSE RABBIT

Anca ŞEICARU Faculty of Veterinary Medicine of Bucharest, SplaiulIndependenței 105, sector 5, Email: [email protected];

Abstract In the present study it was investigated some lymph nodes in the: cephalic region, cervical region, limbs region, and also the cavitary lymph nodes - abdominal cavity. The lymph nodes have generally at this species a grey-ash colour being represented by several lymphonodal units. The lymph nodes at house rabbit have a lighter colour when compared to other rodents. The perilimfonodular amount of fat tissue is reduced compared with other laboratory rodents. Through the regional and stratigraphical dissection have been kept the physiological relations between lymphnodes and the formations close to them. In this investigated regions it was made also the dissection of the vascular-nervous formations of the musculature. Keywords: home rabbit, lymph nodes, dye, lymphatic vessels.

Introduction Extending the knowledge of the at leporidae brings additions and justifies the research in this field, and the new particularties described will supplement the scientific knowledge (Azargoshas B.K., 1963, Ciudin Elena, 1996, ViorelDanacu, et. al., 2013). The laboratory rodents are commonly used for testing a vast array of drugs. Knowledge of the topography and morphology of the lymphatic system at this species can provide an assessment with respect to its pathological aspects. In laboratory, the examination of the lymphatic structures orientates from the necropsy point of view, not only for the diagnose establishing.These animals are also used as pets (Baciu I., 1977,Predoi, G., Belu, C., 1995, Predoi, G., Belu, C., 2001)

Materials and methods For this study were usedfive house rabbits of both sexes, Oryctolaguscuniculus species, all clinically healthy. The rabbits belong to the Leporide family, Lagomorpha order, Glires supraorder. The animals were separated in the group of growth for three days before the injection of the dye. For the morphotopographical study of some lymph nodes was used China ink solution 40% saline, 20 minutes filtered through a filter paper before using. Injection of the dye solution was carried out in the following points of election: plantar and palmar pads until forming a local intradermic button (dose of 0.5 ml); tip of the nose, caudal face of the concha, lower lip (dose of 0.3 ml); nearby the flank region (dose of 0.2 ml). Abdominal lymph nodes were stained by the method of intraperitoneal injection on the white line, in separate points, with ink dye in a dose of 1.5 ml, where syringes with atraumatic needle were used. The visualization of the lymphatic vessels after injecting the dye was needed because the dye was crossing them rapidly. The lymph nodes remain coloured for a long time. The methods used were stratigraphical and regional dissection, using also the stereomicroscope Nikon.

110 Results and discussions Cephalic lymph nodes Mandibular lymph centres represented by rostral and aboral mandibular lymph nodes. The rostral mandibular lymphnode is represented by a lymphatic formation about 0.5 mm length with oval appearance. Is situated on the ventral and cranial edge of the jaw, nearby the facial vein, near the ventral edge of pterygoid medial muscle. The aboral mandibular lymph nodes appear disposed behind the lingofacial vein. They are represented by two lymph nodes, in size of 0.6 mm and 0.4 mm respectively, with oval form, located close to each other(figure 1).

Figure 1– Mandibular lymph nodes 1 – Ln.parotidian at the origin of transversal face artery and vein; 2 – Ln.mandibular on the sublingual artery; 3 – M.masseter; 4 – M.buccinator.

Afferent lymphatic vessels are coming from the portion of the upper region of the neck. Efferent lymph vessels are tributaries for ventral superficial . Parotid is represented by an oval lymph node of about 0.7 mm along the course of the transversal face artery and vein. It is disposed caudal by the masseter muscle and anterior by the parotid gland and it is not covered by the parotid gland. Afferent vessels come from the parotid region, the dorsal half of the head region, the mastoidian region. Efferent lymph vessels are tributaries to superficial cervical lymph nodes.

The anterior limb lymph centre The axillary accessory lymph nodes are represented by twonearby unequal lymph nodes (0.3-0.5 mm), which are rounded. They are disposed close by thoracodorsal artery and vein. Afferent lymphatic vessels are coming from the medio-caudal portion of the thoracic limb. The efferent lymhpatic vessels are tributary to the own axillary lymph node (figure 2).

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Figure 2 – Axillary accessory lymph nodes 1- Axillary accessory lymph nodes; 2 – The long portion of brachial triceps muscle; 3 – Subscapular muscle; 4 – Great wide dorsal muscle; 5 – Thoracodorsal artery and vein

The pelvic limb lymph nodes The subiliac lymph node is disposed at the cranial edge of the fascia lata tensor muscle, near the ilium bone. Here appear two globular lymph nodes (figure 3). The subiliac lymph node is located on the deep circumflex iliac artery.

Figure 3. Subiliac lymph nodes 1 – Ln.subiliac; 2 – Ventrolateral abdominal musculature; 3 – Cranial edge of tensor of fascia lata muscle; 4 – The branch of deep iliac circumflex artery.

The abdominal cavity lymph centres The cranial mesenteric lymph centres represented by a lymph centre, in size of 1.7 cm, on the origin of the cranial mesenteric artery (figure 4). Afferent lymphatic vessels are collecting the lymph from the jejunum and ileum. Efferent lymph vessels participating in the formation of visceral lymphatic trunk.

112 Gastric lymph nodes are formed by two groups of lymph nodes of two ovoid lymphatic structures near the pylorus (figure 5). This gastric lymph nodes have a dimension of 2 mm. Jejunal lymph nodes appear on jejunal arteries path, perpendicular branch and have dimensions of about 2 mm. Afferent lymphatic vessels come in from the jejunum and ileum. The efferent lymphatic vessels are tributary to the cranial mesenteric lymph centre (figure 6).

Figure 4 Cranial mesenteric artery 1 – Cranial mesenteric lymph nodes; 2 – Jejunal lymph nodes; 3 – Cranial mesenteric artery; 4 – Jejunal artery branches; 5 – Jejun; 6 – Ascending colon; 7 – Cecum.

Figure 5 – Gastric lymph nodes 1 – Gastric lymph nodes; 2 – Oesophagus; 3 – Pylor; 4 – Left extremity.

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Figure 6 - Jejunal lymph nodes 1 – Jejunal; 2 – Descending colon; 3 – Jejunal lymph node; 4 –Small mesenteric.

Conclusions At leporidae great epiploon is a lymphoid structure due to the existing peritoneal macrophages. Subiliac lymph nodes are disposed at this species in the flank region, nearby the ilium bone and it can be palpated transcutaneous. Mandibular lymph nodes cannot be palpable transcutaneous and are located in a small amount of fat. The axillary accessory lymph node is located near the half tricipital lane. The cranial mesenteric lymph centre ishighly developed, being formed by many small lymph nodes. This lymph centre in surrounding the origin of the mesenteric cranial artery, where is located.

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