The distribution and function of aquaporin 1 and 2 along the kidney in different species / Distribución y función de la acuaporina 1 y 2 a lo largo del riñón en diferentes especies

SUMMARY: Water metabolism in kidney is critical for organisms living in arid environments. In this study, the kidney structure and the expression of AQP1 and AQP2 in Phrynocephalus vlangalii and Camelus bactrianus were studied. It was found that the Phrynocephalus vlangalii has fewer renal corpuscle but developed kidney tubules, and AQP1 and AQP2 were mainly expressed in the kidney tubules. Camelus bactrianus has a large diameter of glomerulus, thick bulbar membrane, and long and dense urinary tract. AQP1 was highly expressed in the proximal convoluted tubule, proximal straight tubule, and Ansa nephroni (Henle´s loop), and AQP2 was also highly expressed in the collecting tubule and distal convoluted tubule. In the long-term evolutionary adaptation, the morphological structure of animal kidney is consistent with its environment. In addition to structural and functional adaptation, aquaporin also participates in the adaptation to water scarcity environment, and may also play a key role.

RESUMEN: El metabolismo del agua en los riñones es fundamental para los organismos que viven en ambientes áridos. En este estudio, se estudió la estructura renal y la expresión de AQP1 y AQP2 en Phrynocephalus vlangalii y Camelus bactrianus. Se encontró que Phrynocephalus vlangalii tiene menos corpúsculos renales. pero desarrolló túbulos renales, y AQP1 y AQP2 se expresaron principalmente en los túbulos renales. Camelus bactrianus tiene un glomérulo de gran diámetro, una membrana bulbar gruesa y un tracto urinario largo y denso. AQP1 se expresó en gran medida en el túbulo contorneado proximal, el túbulo recto proximal y el Ansa nephroni o asa nefrónica (asa de Henle), y AQP2 también se expresó en gran medida en el túbulo colector y el túbulo contorneado distal. A largo plazo, en la adaptación evolutiva la estructura morfológica del riñón animal es coherente con su entorno. Además de la adaptación estructural y funcional, la acuaporina también es parte de la adaptación al entorno de escasez de agua y puede desempeñar un papel clave.

Expression of aquaporin 2, aquaporin 3 and aquaporin 4 in renal medulla of Bactrian camel ( Camelus bactrianus ) / Expresión de acuaporina 2, acuaporina 3 y acuaporina 4 en la médula renal del camello bactriano ( Camelus bactrianus )

SUMMARY: Aquaporins (AQPs) are members of the aquaporin water channel family that play an important role in reabsorption of water from the renal tubular fluid to concentrate urine. Using immunohistochemical staining on paraffin sections, We studied expression of AQP2, AQP3 and AQP4 in renal medulla of Bactrian camel (Camelus bactrianus). The renal medulla of cattle (Bos taurus) acted as the control. Compared with the control, strong expression of AQP2 was observed at the apical plasma membrane and intracellular vesicles, in both the outer medullary collecting duct (OMCD) and the inner medullary collecting duct (IMCD) of camel. Strong expression of AQP3 was observed at the basolateral plasma membrane of the IMCD of camel. Strong AQP4 expression, however, was observed at the basolateral plasma membrane in the OMCD of camel. Moreover, moderate AQP4 expression was detected in endothelium of capillary in medullary region of camels, whereas very weak/absent expression was detected in endothelium of capillary of cattle. We concluded that expression of AQP2, AQP3 and AQP4 in the camel kidney showed some differences from cattle in renal trans-epithelial water transport. It may enhance our better understanding of special water metabolism mechanisms that enable camels to survive in extreme environments.

RESUMEN: Las acuaporinas (AQP) son miembros de las proteínas de transporte que desempeñan un papel importante en la reabsorción de agua del líquido tubular renal para concentrar la orina. Estudiamos la expresión de AQP2, AQP3 y AQP4 en la médula renal del camello bactriano (Camelus bactrianus) usando tinción inmunohistoquímica en secciones de parafina. La médula renal del bovino (Bos taurus) se usó como control. En comparación con el control, se observó una fuerte expresión de AQP2 en la membrana plasmática apical y vesículas intracelulares tanto en el conducto colector medular externo (CCME) como en el conducto colector medular interno (CCMI) del camello. Se observó una fuerte expresión de AQP3 en la membrana plasmática basolateral del CCMI del camello. También se observó una expresión fuerte de AQP4 en la membrana plasmática basolateral en el CCME de camello. Además, se detectó una expresión moderada de AQP4 en el endotelio de los capilares en la región medular de los camellos, mientras que en el endotelio de los capilares del bovino se detectó una expresión muy débil. Concluimos que la expresión de AQP2, AQP3 y AQP4 en el riñón de camello mostró algunas diferencias con el bovino en el transporte trans-epitelial de agua renal. El estudio podría mejorar nuestra comprensión de los mecanismos especiales del metabolismo del agua que permiten a los camellos sobrevivir en ambientes extremos.

OBSERVATION ON THE ARCHITECTURE OF SUBPLEURAL PULMONARY MICROVASCULATURE IN BACTRIAN CAMEL (CAMELUS BACTRIANUS) UNDER SEM / 解剖学报

Objective To study the architecture of the subpleural pulmonary microvasculature and its functional relationship in the bactrian camel. Methods The replica scanning electron microscopic method was used. Results According to their continuous branches,the subpleural pulmonary microvasculatures were recognized into four grades: arteriole,terminal arteriole,precapillary arteriole and capillary.The subpleural pulmonary capillaries generally came from the subpleural precapillary arteriole and communicated each other to form the subpleural pulmonary capillary network.Sometimes,the subpleural terminal arteriole directly gave rise to capillaries to unite with the subpleural pulmonary capillary network.The network was loose,in which the diameter of the mesh was larger than that of the capillary,and the mesh was often hexagon and pentagon in appearance.There were obvious imprints of the smooth muscles on the surface of the casts of the subpleural pulmonary arteriole,the terminal arteriole and the precapillary arteriole.On the surface of the casts of the subpleural pulmonary capillary,there were obvious imprints of the endothelial nuclei as well.In addition,the broad and different level communications were found among the pulmonary interstitial capillary and subpleural pulmonary microvasculature.Conclusion There were no significant differences on the architecture of the subpleural pulmonary microvasculature between the bactrian camel and other kind of mammals.