ABSTRACT
Regeneration of the renal tubules in rats, after death of the cells of the pars recta caused by a dose of 1.5 mg HgCl2/kg, was examined by histological and radioautographic methods. The tubules regenerated from surviving squamoid cells at both ends of the necrotic segments, which often appeared to arise from epithelial cells that had cast off superficial "dead cytoplasm" to leave the basal parts containing the nucleus in a rim of cytoplasm. The tubular epithelium was reconstituted between the 2nd and 5th days by proliferation and sliding extension of the squamoid cells along the tubules and predominantly from the distal end of the necrotic segments where the cell proliferation was extremely active. Inflammation in reaction to the dead cells was insignificant. Although the majority of tubules regenerated in a regular fashion some degree of anomalous epithelial proliferation occurred in patches, predominantly in the junctional area between the pars recta and the loops of Henle and perhaps most frequently in reference to those nephrons with superficial and mid-cortical glomeruli. The exuberant proliferation led to scattered epithelial growths projecting into the lumen of the tubules, and there was evidence that these obstructed the discharge of necrotic debris. Tubular collapse and atrophy leading to the formation of small scars followed, more often affecting the short looped nephrons.
Subject(s)
Acute Kidney Injury/physiopathology , Kidney Tubular Necrosis, Acute/physiopathology , Kidney Tubules/physiopathology , Mercury/toxicity , Regeneration , Animals , Autoradiography , Cell Division , Epithelium/pathology , Kidney Tubular Necrosis, Acute/chemically induced , Kidney Tubular Necrosis, Acute/pathology , Kidney Tubules/pathology , Male , RatsABSTRACT
A light microscopic study of the renal tubulonecrotic lesion in rats given a small dose of HgCl2 is described. The changes consist of a rapidly developing vacuolation of the cytoplasm with loss of basophilic staining within 4 h that leads to cell breakdown, fragmentation and dissolution by 48 h. Nuclear changes appear to set in later. Permanent patchy fibrotic lesions were found in the kidneys at 10 days. The animals pass a large amount of urine of low osmolarity, low Na+, K+ and Cl- for a period of 3 days accompanied by an increased water intake. Nevertheless there appeared to be no water or ionic imbalance between daily inputs and outputs. Blood urea levels were greatly increased for 3 days, but did not return to normal by the 10th day.
