Renal Dysfunction and Tubulopathy Induced by High-Dose Tenofovir Disoproxil Fumarate in C57BL/6 Mice

Abstract

Tenofovir disoproxil fumarate (TDF) is the most preferred antiretroviral medicine in treating human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infections. Recent clinical trials have reported conflicting results on renal toxicity and safety in TDF-treated patients, but reference animal studies, testing high-doses of TDF for renal toxicity, are scarce. In this preclinical study, we investigated whether daily oral TDF administration (200, 500, or 800 mg/kg/d, p.o.) for four weeks induces renal insufficiency in C57BL/6 mice, by evaluating changes in body weight, urine micro-total protein, urinary microalbumin, serum blood urea nitrogen (BUN), and creatinine levels, along with histological examination of kidney samples. In the G3 group (TDF 800 mg/kg/d, p.o.), three mice died on the 17th, 23rd and 26th days, and overall, significant increases in urinary and serum levels were observed after two weeks of TDF treatment. In addition, the proportion of pyknotic epithelial cells and acidophilic cytoplasm in renal tubules was also increased after two weeks, and congestion and hemorrhage were observed in renal tubules after three weeks. Taken together, high-dose TDF treatment of 800 mg/kg/d might lead to renal tubular damage and dysfunction, great enough to cause death in mice, even after a short period of one to two weeks.

Keywords: nephrotoxicity; renal tubulopathy; tenofovir disoproxil fumarate.

Figure 1

Chemical structure of tenofovir disoproxil fumarate (TDF).

Figure 2

Effects of TDF on urine micro-total protein and microalbumin in mice. Forty-eight mice were divided into four groups, and each group (G0–G3) contained 12 mice. Each of the three treatment groups consisted of 12 mice: G1 group (TDF 200 mg/kg/d, p.o.), G2 group (TDF 500 mg/kg/d, p.o.), and G3 group (TDF 800 mg/kg/d, p.o.). Urinary micro-total protein (a) and microalbumin (b) levels of each group measured every week for four weeks were presented as a bar graph. The data are expressed as mean ± S.D. The comparison among the groups was performed by the ANOVA test followed by the LSD test. a: p < 0.05 compared with the G0 group, b: p < 0.05 compared with the G1 group.

Figure 3

Effects of TDF on serum BUN and creatinine levels in mice. Forty-eight mice were divided into four groups, and each group (G0–G3) contained 12 mice. Mice were treated with various doses of TDF (200, 500, or 800 mg/kg/d, p.o.) for four weeks. Serum BUN (a) and creatinine (b) levels of each group measured every week for four weeks are presented as a bar graph. The data are expressed as mean ± S.D. The comparison among the groups was performed by the ANOVA test followed by the LSD test. a: p < 0.05 compared with the G0 group, b: p < 0.05 compared with the G1 group, c: p < 0.05 compared with the G3 group.

Figure 4

Effects of TDF on renal tissue histology in mice. Mice were sacrificed each week over a four week period after TDF administration. Renal tissues were stained with Hematoxylin and Eosin (H&E) (×400). Black circles indicate renal tubular necrotic (pyknotic) cells and black arrows point to congestion and hemorrhage in renal tubules, respectively. Scale bar is 50 μm. (a) G0 group, week 1; (b) G0 group, week 2; (c) G0 group, week 3; (d) G0 group, week 4; (e) G1 group, week 1; (f) G1 group, week 2; (g) G1 group, week 3; (h) G1 group, week 4; (i) G2 group, week 1; (j) G2 group, week 2; (k) G2 group, week 3; (l) G2 group, week 4; (m) G3 group, week 1; (n) G3 group, week 2; (o) G3 group, week 3; (p) G3 group, week 4.