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A reliable and reproducible rodent model of Tenofovir disoproxil fumarate (TDF) (anti-HIV drug) nephrotoxicity that resembles human TDF tubulopathy.

Tenofovir disoproxil fumarate (TDF) is recommended as a first-line therapy in HIV treatment. However, TDF is nephrotoxic especially with long-term use. Early detection of nephrotoxicity and its prevention are key to avoid irreversible renal damage. This requires knowledge of the mechanism of TDF nephrotoxicity. A reliable animal model is therefore necessary to study the mechanism of TDF nephrotoxicity. To standardize a rodent model of TDF nephrotoxicity resembling humans, adult male Wistar rats were used for the studies. Initially the optimal dose and the duration of treatment required to produce nephrotoxicity in rats was established and it was found that a dose of 600 mg/kg body weight for 5 weeks p.o. was required. The histological changes (in the kidney) and biochemical changes (in the serum and urine) were recorded after treatment at different doses of TDF. At this dose the TDF treated rat kidneys showed structural and functional alterations in the proximal tubule resembling that of HIV patients on TDF therapy. The proximal convoluted tubules were distorted and their lining epithelium was absent. Biochemically, the rats exhibited Fanconi syndrome characterized by bicarbonate wasting, phosphaturia, kaluria, low serum bicarbonate and phosphate. TDF dose of 600 mg/kg body wt. which is 12 x the human dose and the treatment period of 5 weeks induces proximal tubular damage and dysfunction that is very similar to that seen in TDF treated humans. Thus, the rat model appears to be a suitable model for the study of TDF nephrotoxicity.

Author(s): Premila Abraham, R Hemalatha, Bina Isaac