Transoral intratracheal inoculation method for use with neonatal rats

Background and Purpose: Studying the effects of toxic and infective compounds on the respiratory system requires a reliable method for delivering inoculum into the distal region of the lung. Although transoral intratracheal inoculation methods have been well documented for adult rats, to the authors' knowledge, a reliable method has not been validated for neonatal rats. The purpose of the study reported here was to develop a simple method for transoral inoculation in rat neonates, Methods: Seven-day-old Fischer 344 rats were anesthetized with halothane, and a spinal needle was inserted in the tracheal lumen, by use of illumination and a modified otoscope, Meconium was injected into the lungs as a marker, and the neonates were kept under close observation After euthanasia at 24 h, lungs were removed and fixed in formalin, and the microscopic distribution of the inoculum was assessed in the left, right cranial, middle, median, and caudal lung lobes. Results: Microscopic examination of lungs indicated that intratracheal inoculation was achieved in 100% of neonatal, lungs and the inoculum was consistently distributed in the alveoli of all pulmonary lobes, Important complications or mortality were not observed in the neonates, Conclusions: Intratracheal inoculation of neonatal rats is possible by use of a modified otoscope for transoral illumination. This technique is simple and reproducible and ensures, without complications, widespread distribution of inoculum in the lungs of neonatal rats.PT: J; CR: *CAN COUNC AN CAR, 1993, GUID CAR US EXP AN BAKER DEJ, 1979, LAB RAT, P154 BECKNELL P, 1996, LAB ANIMAL ANAESTHES, P7 BOORMAN GA, 1990, PATHOLOGY FISCHER RA, P339 BRAIN JD, 1976, ENVIRON RES, V11, P13 CLEARY GM, 1997, PEDIATRICS, V100, P998 CLEARY GM, 1998, PEDIATR CLIN N AM, V45, P511 CUMMINGS EC, 1987, INHAL TOXICOL, P153 EGER EI, 1981, ANESTHESIOLOGY, V55, P559 GREEN CJ, 1981, LAB ANIM, V15, P397 HAYEK A, 1982, LAB ANIM SCI, V32, P171 LAFUENTE VC, 1998, VET MEXICO, V29, P147 LIBBIN RM, 1979, SCIENCE, V206, P66 MARTINEZBURNES J, 1985, CAN J COMP MED, V49, P327 NICHOLSON JW, 1982, LAB ANIM SCI, V32, P509 PARK CM, 1992, LAB ANIM SCI, V42, P508 PHIFER CB, 1986, PHYSIOL BEHAV, V38, P887 PINKERTON KE, 1982, AM J ANAT, V164, P155 PINKERTON KE, 1985, TOXICOLOGY INHALED M, P259 PRITCHARD JN, 1985, ENVIRON RES, V36, P268 REYNOLDS RD, 1981, SCIENCE, V213, P1146 RUZINSKI JT, 1995, LAB ANIM SCI, V45, P205 SUGIMOTO M, 1980, J RETICULOENDOTHEL S, V27, P595 SUN B, 1993, BIOL NEONATE, V63, P96 WAYNFORTH HB, 1980, EXPT SURG TECHNIQUE, P247; NR: 25; TC: 4; J9: COMPARATIVE MED; PG: 4; GA: 428WRSource type: Electronic(1