Histology of Vermiform Appendix-Like Organ in Slow Loris.

Abstract

Abstract:The vermiform appendix-like organ (VALO) of the slow loris was investigated for its histology and immunohistochemical characteristics. The VALO has a much thinner wall with flat folded mucosa and shallower crypts than the cecal mucosa, while cellular components and population of the mucosa were similar to those of the cecum. No coalescent lymph nodules were seen in the submucosa. Immunohistochemically 5-HTpositive cells in the crypts and CD3-and CD8-positive lymphocytes in the lymph nodules were shown in the VALO as well as in the cecum. These findings suggest that the VALO is a low-differentiated vermiform appendix of the slow loris. Key words: slow loris, vermiform appendix-like organThe slow loris (Nycticebus coucang) is a prosimian species distributed throughout South-East Asia, and is characterized by unique slow locomotion. To clarify the details of the anatomical and histological features contributing to its locomotion, the locomotive [4,16,17], optical [7] and nervous [8][9][10][11][12] organs have been reported by many researchers. However, little information is available concerning the digestive organs of the slow loris, except for the vermiform appendix-like organ (VALO) at the blind-end of the cecum [18]. It is very interesting that VALO bears an apparent resemblance to the vermiform appendix, which is observed in the old world monkey [15]. The VALO is considered to be useful for understanding the role of the vermiform appendix in primates. The objectives of this study were to establish histological and immunohistochemical characteristics of the VALO of the slow