Histological and Urinalysis Assessment of Nephrotoxicity Induced by Mercuric Chloride in Normal and Uninephrectomized Rats

Abstract

Assessment of the health threat to human populations that have been exposed to nephrotoxic metals requires accurate information about relationships between exposure and renal function. Currently, urinalysis is relied on heavily for the evaluation of impairment of renal function and for describing dose-response relationships in numans (Gotelli et al., 1985; Roels et al., 1981; Stonard et al., 1983; Thun et al., 1985). This is because urine is the one biological product of renal function that can be readily sampled in field studies. The rationale for using urinalysis is to detect the increased excretion of marker substances that are normally conserved by physiological mechanisms susceptible to injury by metals. The most useful urinary markers are those that reflect the severity of functional impairment and that can be detected in the early stages of renal toxicity, hopefully before irreversible injury has occurred. Many different urinary markers have been used; including glucose (Falck et al., 1983; Tohyama et al., 1982) amino acids (Bernard et al., 1979; Buchet et al., 1980; Clarkson and Kench, 1956; Thun et al., 1985) plasma proteins (Bernard et al., 1979; Buchet et al., 1980; Falck et al., 1983; Roels et al., 1981; Stonard et al., 1983; Thun et al., 1985) and cellular enzymes (Bernard et al., 1979; Buchet et al., 1980; Gotelli et al., 1985; Stonard et al., 1983). Clearly, the selection of urinary markers that are appropriate for the anticipated form of toxicity is important. Analytical procedures that enable the investigator to describe variability within the urinalysis results due to variation in sampling time, urine flow rate and body mass of the subjects being studied are also required for accurate interpretation of urinalysis data.