JPC SYSTEMIC PATHOLOGY
Signalment (JPC #1713077): Multiple male mice
HISTORY: An accident in the hallway of a laboratory animal facility resulted in the leakage of several bottles of chloroform. The following day many male mice housed in the facility were found dead.
HISTOPATHOLOGIC DESCRIPTION: Kidney: Multifocally proximal tubular epithelial cells are swollen with pale granular cytoplasm (degeneration) or cells are hypereosinophilic with retention of cytoplasmic detail and multifocal nuclear pyknosis or karyolysis (necrosis). The tubule epithelial cells in these areas are either attenuated or swollen with numerous intracytoplasmic, variably sized (up to 15um diameter) eosinophilic hyaline globules. Multifocally within the cortex there are moderate numbers of mildly dilated renal tubules that contain bright eosinophilic homogenous fluid (proteinosis) or granular eosinophilic cellular debris. Less affected cortical and medullary tubules are dilated and contain proteinaceous fluid. There is a focal aggregation of lymphocytes in the medulla.
MORPHOLOGIC DIAGNOSIS: Kidney, tubules: Degeneration and necrosis, acute, multifocal, moderate, with tubular proteinosis, mouse, rodent.
ETIOLOGIC DIAGNOSIS: Chloroform nephrosis
CAUSE: Chloroform (CHCI3)
- Prototypical organohalide
- Chloroform toxicity results in acute coagulative renal tubular necrosis (especially proximal tubules) in male mice and hepatotoxicity in males and females
- Male DBA and C3H mice are especially sensitive due to the presence of cytochrome P450 isoenzyme 2E1; F344 rats are also sensitive but less so than these mouse strains
- Castration eliminates the nephrotoxic effects in male mice due to decrease of renal cytochrome P450 and incites nephrotoxic effects in female mice treated with testosterone
- Inhalation or ingestion of chloroform
- Increased binding of chloroform in males (6 x that of females) because the action of chloroform is mediated via the androgen receptor
- Metabolism of chloroform (CHCI3) to unstable trichloromethanol to phosgene (COCI2) occurs in the proximal renal tubule epithelium by cytochrome P-450 (mixed function oxidase) system
- Phosgene depletes renal glutathione resulting in autocatalytic peroxidative degradation of membranes > glutathione conjugation with chloroform metabolites reduces or prevents covalent binding with tissue macromolecules
- Covalent adduct formation with DNA may cause renal and hepatic carcinomas in rats
TYPICAL CLINICAL FINDINGS:
- Lethargy, tremors and convulsions
- Death 1-10 days later
- Deaths may be primarily in male animals
- Clinical Pathology:
- Elevated BUN, ALP, ALT, AST, CK
TYPICAL GROSS FINDINGS:
- The kidneys are pale and enlarged with a finely granular surface
- White capsular mottling and cortical streaks due to calcification of necrotic tubules (nephrocalcinosis) may occur in survivors
TYPICAL LIGHT MICROSCOPIC FINDINGS:
- Coagulative necrosis of primarily proximal renal tubular epithelial cells
- Tubules may contain hyaline casts and protein
- The glomeruli, collecting tubules and renal papilla are not affected
- Hepatic lesions are characterized by centrilobular necrosis, fatty degeneration of hepatocytes and nodular hyperplasia
- Myocardial and neuronal degeneration and lymphocytic necrosis
- Swelling of tubular epithelial cells
- Swollen mitrochondria
- Dilated and fragmented endoplasmic reticulum
- Loss of villi
- Focal rarefaction of cytplasmic matrix
- Renal tubule damage is nonspecific; mercury bichloride, uranyl nitrate, and potassium dichromate produce similar lesions
- Chloroform and 1,1,2-trichloroethane are the only chlorinated compounds that produce severe renal disease
- Susceptibility to chloroform nephrotoxicity is a species- and sex-specific response of the male mouse
- F-344 male rats are susceptible but require a higher concentration
- Mice and rats are used as animal models for acute and chronic chloroform nephrotoxicity and hepatotoxicity
- Inudces hepatocellular carcinomas in B6C3F1 mice and renal epithelial tumors in Osborne-Mendel rats in long-term studies
- Gathumbi PK, Mwangi JW, Mugera GM, Njiro SM. Toxicity of chloroform extract of Prunus Africana stem bark in rats: gross and histologic lesions, Phytother Res. 2002 May; 16(3):244-7.
- Haschek WM, Rousseaux CG, Wallig MA. Kidney and lower urinary tract. Fundamentals of Toxicological Pathology. 2nd ed. San Diego, CA: Academic Press; 2010:287.
- Miller MA, Zachary JF. Mechanisms and morphology of cellular injury, adaptation, and death. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. Saint Louis, MO: Elsevier; 2017:13.
- Percy DH, Barthhold SW. Pathology of Laboratory Rodents and Rabbits. 4th ed. Ames, Iowa: Iowa State University Press; 2016:107-108.
- Sebastian MM, Baskin SI, Czerwinski SE. Renal toxicity. In: Gupta RC, ed. Veterinary Toxicology. 1st ed. San Diego, CA: Elsevier; 2007:162-163.
- Sehata S, et al. 26 week carcinogenicity study of chloroform in CB6F1 rasH2-transgenic mice. Toxicol Pathol. 2002 May-Jun;30(3):328-38.
- Schnellmann RG. Toxic responses of the kidney. In: Klaassen CD, ed. Casarett and Doull’s Toxicology, The Basic Science of Poisons. 6th ed. San Francisco, CA; McGraw-Hill; 2001:508.