Change Trends of Organ Weight Background Data in Sprague Dawley Rats at Different Ages

Organ weight is one of the most sensitive drug toxicity indicators, and its changes often precede morphological changes. So far, no background data about organ weight and its coefficient in SD rats at different weeks of age have been reported in China. The aim of this study was to summarize and analyze the change trends of organ weight and organ weight coefficients in SD rats at different weeks of age. The absolute of the weights of the brain, spleen, heart, lungs, liver, kidneys, adrenal glands and testes were increased in male SD rats from 13 to 78 weeks, and the weights of the brain, heart, lungs, liver, kidneys and especially the testes were decreased from 78 to 104 weeks. On the other hand, the absolute weight of the adrenal glands showed an increasing trend from 13 to 104 weeks. The absolute weight of the brain, spleen, heart, lungs, liver, kidneys, adrenal glands and ovaries showed an increasing trend from 13 to 104 weeks. A significant increase was observed in adrenal gland and ovary weights, whereas no obvious change trends were observed for the other organ weights mentioned above. It was surprising that the absolute of weight of the adrenal glands and organ-to-brain and organ-to-body weight ratios in female rats were significantly higher than those in males from 13 to 104 weeks. This study was the first to establish background data for organ weights in SD rats at different weeks of age and their reference ranges in line with the experimental animal status in China and to summarize their summarized their changes trend. (DOI: 10.1293/tox.26.29; J Toxicol Pathol 2013; 26: 29-34)