Study of Volumetric Changes of Rat's Embryonic Renal Glomeruli, Cortex and Medulla Following Lithium Carbonate Administration by Means of Stereological Method

Purpose: To study the effects of lithium on the fetal rat's kidney and determine volumetric changes by an unbiased stereological method. Materials and Methods: Thirty female and ten male Sprague dawley rats were chosen. Following cohabitation and observation of spermatozoa in the vaginal smear, the pregnant rats were divided into three groups (n=10). Treatment and control groups received 50 mg/kg lithium carbonate in distilled water and the same volume of normal saline by intraperitoneal injection on 7th, 10th, 13th, 16th and 19th days of gestation, respectively. On 20th day of gestation, under deep anesthesia, the right kidneys of the rats were dissected and fixed in modified Lillie's solution. Then tissue processing was performed, and 5-micrometer sections were cut and stained with H & E. To determine the volume parameters of the kidneys, a stereological technique based on Cavalier's principle was used. Results: The study showed that lithium could cause a significant decrease in the glomerular volume (52%), total volume (44%) and volume of the cortex (42%) and medulla (49%) of the kidney. Conclusion: Administration of lithium during pregnancy has effects on the volume of different parts of fetal kidneys, especially on glomeruli. Since normal volumetric parameters are indicators of renal development, it seems that lithium causes some defects in the normal development of the kidney.