2733 2011Microscopic Anatomy of the Lower Respiratory System ofthe - PDF document

:27-33, 2011.Microscopic Anatomy of the Lower Respiratory System ofthe African Giant Pouched Rat (Cricetomys gambianus,Waterhouse 1840)Anatom’a Microsc—pica del Sistema Respiratorio Inferior de laRata Gigante Africana (Cricetomys gambianus, Waterhouse 1840) Waterhouse 1840). :27-33, 2011.SUMMARY:A qualitative and quantitative study, by light microscopy, was undertaken on the lower respiratory system of theAfrican Giant pouched rat. Specifically, the trachea, bronchi and lungs were stained with Haematoxylin and eosin, Alcian blue a2.5 and Periodic Acid-Schiff stains. Three cell types were identified in saggital sections of the trachea: the ciliated cells, Mucous thebronchi and respiratory bronchiole. Some tracheal cartilaginous rims stained blue with AB while most glandular cells stained rePAS. The diameter of respiratory bronchiole, alveoli duct and alveoli were 24.93 1.27), 21.14 0.66) and 12.95 0.21),respectively. These and other findings were compared with similar report in other rodents.KEY WORDS: African Giant pouched rat; Lower respiratory system; Histology.The African Giant pouched rat is one of the two alongside the EminÕs). It is among the largestrodent. This is not surprising because of the catalogue ofin food security. They have been successfully used to detect2003) due to high acuity of odour perception. They also serveas exotic pets (Cooper, 2008) and are proposed as laboratoryconditions (Olayemi & Adeshina, 2002).o better understand the African Giant pouched rat,for future biomedical investigations is paramount. Thus, severalinvestigators have made pioneering efforts to characterise 1995, 1988a, 1988b; Oke & Aire, 1989, 1990; Akinloye ., 2000; Widdicombe ., 1972) have been described in detail. However, suchdescription in the African Giant pouched rat is lacking. Theanatomy of the African Giant pouched rat was the grosstree reported by Valerius (1996). Department of Veterinary Anatomy, Ahmadu Bello University, Zaria, Nigeria. epithelial cells. The respiratory mucus gel, in conjunctionÒescalator,Ó which, along with cough, is essential for the& Sheehan, 2004). Although the cellular composition of themilar, pronounced differences exist in the distribution pattern(Reznik, 1990). These differences have been reported in theregional distribution of tracheal mucous gland in different; Widdicombe cells that build the air-

blood barrier and type II cells thatsynthesize and secrete surfactant. The lung surfactantproteins A and D are part of the pulmonary innate immunesystem (Wu ., 2003; Wright, 2004; Jung in the African Giant pouched rat, in order to add to theavailable information on the anatomy of the rodent. Thethe trachea, bronchi and lungs, to describe the regionaldistribution of the tracheal mucous glands and finally, toinvestigations regarding the respiratory system of the AfricanMATERIAL AND METHODhealthy African Giant pouched rats with an average weightof 1.07 Kg, were utilized for this study. The animals wereand measuring 1.0 m x 0.8 m x 0.8 m were used. The ratsof Veterinary Anatomy, Ahmadu Bello University Zaria,Tissue Processing. The rats were euthanized by intra-peritoneal injection of lethal dose of Thiopental Sodium(Rotexmedica, Trittau. Germany). With the animals on a dor-sal recumbency, tracheotomy through the ventral cervicalbuffered formalin, using a cannula. When the fixative stoppedposition for about four hours. The ventral cervical region andentire thoracic cavity were exposed surgically to reveal thelower respiratory system. The lungs were physically examinedThey were also fully expanded. This was evident by the factcavity. The lower respiratory system was exteriorized andfreed from other thoracic viscera. The trachea, principalbronchi and lungs were separated. These organs were fixedin 10 % phosphate-buffered formalin for three days.Thereafter, the samples were washed in water and kept thereinfor twenty four hours. Further processing involvedalcohol in that order, leaving them in each solution of alcoholfor an hour. The tissues were cleared in xylene, infiltratedwith molten paraffin wax (BDH Chemicals Ltd. Poole,England) at 60 0C, blocked in paraffin according to standardGermny). The sections were mounted on glass slides, dried,deparaffinized, stained, dehydrated, and coverslipped, usingHistomorphological Featureshistomorphology. Specifically, three regions of each tracheawere processed. These were; the trachea rings just caudal toeach principal bronchus was used. These tissues were stainedwith Haematoxylin and eosin (H/E), Alcian blue (AB) at apH of 2.5 and Periodic Acid-Schiff (PAS). H/E was used ton blue and PAS were adopted to differentiateMicroscopic anatomyof the lower respiratory system of the African giant pouched rat ( Waterhou

se 1840).:27-33, 2011. the conventional H/E. They were also stained with PAS toglycoproteins and with AB at a pH of 2.5 to demonstrate theConductive Airway. Trachea and principal bronchi of foursamples sectioned in the saggital plane and stained with ABand PAS were used to determine the regional distribution oftracheal mucous gland. The rostrocaudal extent of eachobtained by trimming each of these three parts. Thesemicroscope (OLYMPUS¨ Ð XSZ107BN, Hamburg,Germany). The regions of the tracheal epithelium occupiedobserved. This process was repeated until the entire lengthof section on the slide was studied. This was repeated forwere restricted to the respiratory portion of the lungs. This20 alveoli ducts and 64 alveoli. The diameters of the aboveocular micrometer (Leitz Wetzlar, Germany) and stagemicrometer (Graticules Ltd., London). A magnification fac-the light microscope (OLYMPUS¨ Ð XSZ107BN, Hamburg,Germany). This objective lens and the ocular micrometer(Leitz Wetzlar, Germany) were used for thehistomorphometry. The respiratory bronchioles and alveolioff alveolar sacs unlike the latter.RESULTSHistomorphological Features. Histologically, the tracheaof the African Giant pouched rat was clearly divided intothe cartilages from the epithelial layer (Fig. 2). The left andbranched off from the main bronchi. They consisted ofbronchioles (Fig. 3). The respiratory bronchioles continuedas alveolar ducts. The alveolar ducts opened into numerousalveolar sacs (Fig. 3). At a higher magnification (insert inobserved. This included simple squamous epithelial cellsinterspaced by simple cuboidal cells. The former were theType I pneumocytes while the latter were the Type IIAccording to Wilson mucosubstances and polysaccharides stain blue with the ABpolysaccharides stain red with the PAS stain. In utilizingrims stained blue with AB while most glandular cells stainedred with PAS.Fig. 1. Saggital section of the proximal trachea of the African Giantpouched rat, illustrating A: Epithelial cells. B: Membranous partFig. 2. Saggital section of the proximal trachea of the African Giantpouched rat, illustrating A: Respiratory epithelium. B: Trachealismuscle. C: Cartilage. PAS X 400Microscopic anatomyof the lower respiratory system of the African giant pouched rat ( Waterhouse:27-33, 2011. Regional Distribution of Tracheal Mucous Glandwas no significant difference in

the regional distribution ofmucous glands between the African Giant pouched rats. Inthe rostral trachea than the caudal trachea. The carina wasfree of mucous glands. The glands were predominant in the1). The cartilages were devoid of glands. They were more. The result of the avera-bronchioles and alveoli spaces were represented in Table Iwith the number of counted structures in parentheses. Theparticles. This important lung-protective function dependsboth on the availability and subsequent efficiency of mucosal. (2011) recorded 0.03) with an average of5.32 mm in the rostral trachea in the African Giant pouchedrat. In the present study, tracheal mucous glands werepredominant in the rostral trachea. This agrees with the li-. Widdicombe to their small tracheal diameter of approximately 1 mm. Theyobserved tracheal glands in other rodents such as hamster, rat1.5 mm, 2.5 mm and 2.5 mm respectively.the African Giant pouched rat. This is similar to what was et al (1997), Choi . and Widdicombe Similarly, Kennedy . and Reznik reported thattrachea of hamsters, near the larynx. Conversely, Choi . reported absence of mucous gland in the entire tracheafor the African giant pouched rat.Fig. 3. Coronal section of lung tissue of the African Giant pouchedthe alveoli spaces. A: lobar bronchus. B: Segmental bronchus. C:Respiratory bronchiole. D: Alveoli duct. E: Alveoli spaces. F:Pulmonary artery. H/E X 100. Insert shows Type I (i) and Type II StructureMinimum diameter (m)Maximum diameter (m)Mean diameter (m) ( SEM)Respiratory bronchioles (18)21.4027.7624.93 ( 1.27)Alveolar ducts (20)18.5125.4021.14 ( 0.66)Alveoli (64)11.4816.2912.95 ( 0.21)Table I. Sizes of airway structures in the African Giant pouched rat.Microscopic anatomyof the lower respiratory system of the African giant pouched rat ( Waterhouse 1840).:27-33, 2011. The tracheal epithelium recorded in the present studyHowever, Kennedy goblet cells. This is not similar to the result of the presenthamster. They also recorded an average diameter of 130 respectively. These values are very high, compared to thevalues we obtained in the African Giant pouched rats. TheSyrian Golden hamster is smaller in size than the AfricanGiant pouched rat. They have an average bodyweight of 125African Giant pouched rat. This finding supports the initial(2011) that the respiratory system of theless efficient when compared to

that of other smaller rodents.The works of Lindstedt (1984) and Valerius have alsosize of respiratory organs. The effect of the poorly developedrespiratory system to the habitat and life style of the AfricanIn the present study, histological features of the lowerrespiratory system in the African Giant pouched rat weresuggested that the lower respiratory system in the Africancompared to those of the Syrian golden hamster. Thus, thelower respiratory system in the African Giant pouched rat Anatom’a microsc—pica del sistema respiratorioinferior de la rata Waterhouse 1840). :27-33, 2011.Se realiz— un estudio cualitativo y cuantitativo, mediante microscop’a de luz, en el sistema respiratorio inferior dela rata gigante Africana. La tr‡quea, los bronquios y los pulmones fueron te–idos con hematoxilina y eosina, azul Alci‡n a pH ‡cido peri—dico de Schiff. Tres tipos de cŽlulas fueron identificadas en las secciones sagitales de la tr‡quea: cŽlulas ciliadasegmentarios respiratorias. Algunos bordes azules cartilaginoso traqueal manchada con AB, mientras que la mayor’a de las cŽlulaglandulares te–ido de rojo con PAS. El di‡metro de los bronquiolos respiratorios, conductos alveolares y los alvŽolos fueron 24 0,66) y 12,95 m ( 0,21), respectivamente. Estos y otros resultados se compararon con el informe similar en otrosPALABRAS CLAVE: Rata gigante africana; Sistema respiratorio inferior; Histolog’a. Ajayi, S. S. Observations on the biology, domestication andreproductive performance of the African Giant rat, Waterhouse) in Nigeria.Akinloye, A. K., Oke, B. O. & Soley, J. T. Ultrastructuralfeatures of the vagina at different phases of oestrus cyclein the female African giant rats (Cricetomys gambianus,Waterhouse). Proceedings of the 44 Annual Congressof the Nigerian Veterinary Medical Association(NVMA), 112-6, 2007.S. M., Umosen, A. D., Alphonsus, C. & Nzalak, J. O.of the wild African Giant pouched rat (Chabot, S., Salez, L., McCormack, F. X., Touqui, L. &Chignard, M. Surfactant protein A inhibits lipopo- production of interleukin-10J. Respir. Cell Mol. Biol., 28Microscopic anatomyof the lower respiratory system of the African giant pouched rat ( Waterhouse 1840).:27-33, 2011. Choi, H. K., Finkbeiner, W. E. & Widdicombe, J. H. AJ. Anat., 197Cooper, R. G. Care, husband

ry and diseases of the AfricanJ. S. Afr. Vet. Med.Gardai, S. J., Xiao, Y. Q., Dickinson, M., Nick, J. A., Voelker,D. R., Greene, K. E. & Henson, P. M. By binding SIRPCell, 115Goco, R. V., Kress, M. B. & Brantigan, O. C. ComparisonAnnals of the New York Academy of Sciences,Hayashi, M., Sornberger, G. C. & Huber, G. L. MorphometricAm. Rev. Respir. Dis., 119Ibe, C. S., Onyeanusi, B. I., Ayo, J. O., Salami, S. O. &Preliminary neuroanatomical study of thevisual and auditory senses in the African Giant pouchedrat (Cricetomys gambianus Waterhouse-1840). Annual Conference of theNigerian Society for Animal Production (NSAP), pp.Ibe, C. S., Onyeanusi, B. I., Hambolu, J. O. & Ayo, J. O.morphometry in the African Giant pouched rat, Waterhouse - 1840). Ibe, C. S., Onyeanusi, B. I., Salami, S. O. & Ajayi, I. E.Waterhouse-1840). J. Vet. Anat. 3 (2)Ibe, C. S., Onyeanusi, B. I. Nzalak, J. O. & Ajayi, I. E. Onthe structure of the spleen in the African Giant pouchedWaterhouse 1840). Vet. Res.Ibe, C. S., Salami, S. O. & Onyeanusi, B. I. Macroscopicburrowing rodent: African giant pouched rat ( Waterhouse 1840). :112-119, 2011.Jung, A., Allen, L., Nyengaard, J. R., Gundersen, H. J. G.,Richter, J., Hawgood, S. & Ochs, M. Design-basedarchitecture and alveolar Type II cells in surfactantprotein A and D double deficient mice. Kennedy, A. R., Desrosiers, A., Terzaghi, M. & Little, J. B.J. Anat., 125Kiernan, J. A. theory and practice. Oxford Per-gamon Press, 1990. pp.Kliment, V., Libich, J. & Kaudersova, V. Geometry of gui-Epidemiol. Microbiol. Immunol., 16Lindstedt, S. L. Pulmonary transit time and diffusing capacityAm. J. Physiol. Regul. Integr. Comp.Giant Rats to Sniff Out Tuberculosis. In:www.NewScientist.com news service. 2003. Accessed:16/12/2008. 17:33:32 GMT.Giant African rats used to sniff landmines.news.nationalgeographic.com. 2004. Accessed: 11/09/2009. 07: 20: 34 GMT.Nzalak, J. O., Ayo, J. O., Neils, J. S., Okpara, J. O.,Onyeanusi, B. I., Ghaji, A. & Ojo, S. A. MorphologicStudies of the Cerebellum and Forebrain of the AfricanTrop. Vet., 23Ogwuegbu, S. O., Oke, B. O. & Aire, T. A.male African Giant rat (Waterhouse) in Ibadan, Nigeria. Afr. J. Ecol., 21Microscopic anatomyof the lower respiratory system of the African giant pouched rat ( Waterhouse 1840).:27-33, 2011. Oke, B. O & Aire, T. A. Ultrastrucural evidence of secretionin different zones of the caput ep

ididymis of the African waterhouse). Vet.Archiv., 60Oke, B. O. & Aire, T. A. The bulbourethral gland of Africa Waterhouse)Vet. Archiv,. 59Oke, B. O., Aire, T. A., Adeyemo, O. & Heath, E. Thestructure of the epididymis of the African giant ratWaterhouse). Histological,Oke, B. O., Aire, T. A., Adeyemo, O. & Heath, E. The ultrastructure of the epididymis of the African giant rat Waterhouse). J. Anat., 165Oke, B. O., Oke, O. A. & Aire, T. A. The prostate gland ofthe African Giant rat (Waterhouse). Vet. Arhiv., 65:115-25, 1995.Olayemi, F. & Adeshina, E. Plasma biochemical values inthe African Giant rat (Waterhouse) and the West African hinge backed tortoiseVet. Arhiv., 72Olayemi, F. O., Oke, O. A., Oyewale, J. O. & Ogunsanmi,A. O. The effect of season on the blood profile of the, Waterhouse).Israel Journal of Veterinary Medicine. 56 (4)/www.isrvma.org/article/56_4.htm. 2001. Accessed: 27/07/2007. 05:30:23 GMT.Olude, M. A., Olopade, J. O., Fatola, I. O. & Onwuka, S. K.Some aspects of the neurocraniometry of the African Waterhouse), Onyeanusi, B. I., Adeniyi, A. A., Ayo, J. O. & Nzalak, J. O.Morphometric studies of the kidneys of the African giant Waterhouse). JAVA,6(11)Onyeanusi, B. I., Adeniyi, A. A., Ayo, J.O., Ibe, C. S. &Onyeanusi, C. G. A comparative study on the urinarysystem of the African Giant rat (Waterhouse) and the Wistar rat. Pak. J. Nutr., 8(7)Reznik, G. K. Comparative anatomy, physiology andEnviron HealthRogers, D. F. Airway goblet cells: responsive and adaptableEur. Respir. J., 7Spicer, S. S., Setser, M. E., Mochizuki, I. & Simson, J. A. V.Toward a more coherent understanding of this essentialbarrier. Proc. Am. Thorac. Soc., 1Valerius, K. Size-dependent morphology of the conductiveWiddicombe, J. H., Chen, L. L-K., Sporer, H., Choi, H. K.,Pecson, I. S. & Bastacky, S. J. Distribution of trachealJ. Anat., 198Wilson, T. S., McDowell, E. M. & Trump, B. F. An AlcianNeutral and Acidic Mucosubstances. Wright, J. R. Host defence functions of pulmonary surfactant.Wu, H., Kuzmenko, A., Wan, S., Schaffer, L., Weiss, A.,Fisher, J. H., Kim, K. S. & McCormack, F. X. Surfactantproteins A and D inhibit the growth of gram-negativebacteria by increasing membrane permeability. Invest., 111Dr. Chikera Samuel IbeDepartment of Veterinary AnatomyMicroscopic anatomyof the lower respiratory system of the African giant pouched rat ( Waterhouse 1840).:27-33, 2