Organogenesis of lung and kidney in Thoroughbreds and ponies

Equine lung and kidney organogenesis has not previously been examined with the use of unbiased stereological techniques. The present study examined he althy (control) pony and Thoroughbred lungs and kidneys to establish baseli ne data of organ development from before birth until maturity at age 3-18 y ears. Whole left lungs and kidneys were collected from 45 equine postmortem examinations (34 Thoroughbred, 11 pony). Stereological techniques were use d to estimate whole kidney, cortex and medulla volume, total glomerular num ber and volume-weighted mean glomerular volume, lung volume, total terminal bronchiolar duct ending number and total gas exchange surface area. Lungs were demonstrated to be more developed at birth in ponies compared with Tho roughbreds. Thoroughbreds showed continued lung development after birth, a unique micromorphogenic postnatal development. Kidneys were developed equal ly in ponies and Thoroughbreds. This study has provided data on the baselin e development of the equiune lung and kidney which can be used in further s tudies to examine whether the development of these organs is affected by sp ecific illnesses.