A triglyceride-rich lipoprotein environment exacerbates renal injury in the accelerated nephrotoxic nephritis model

Figures

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  Figure 1. Poloxamer 407 (P‐407)‐induced hyper‐triglyceride‐rich lipoprotein (TGRL) state promotes kidney damage in the accelerated nephrotoxic nephritis (ANTN) model. (a) Schematic representation of the experimental design. A hyper‐TGRL state was induced in B6 mice by injecting 10 mg P‐407 intraperitoneally (i.p.) every other day for 28 days. Phosphate‐buffered saline (PBS)‐injected mice served as controls. Nine days post P‐407 treatment, the mice were immunized with sheep immunoglobulin (Ig)G followed 5 days later by intravenous (i.v.) injection of nephrotoxic serum (NTS). The mice were monitored for a further 2 weeks. Plasma levels of TG (b), cholesterol (CHOL) (c) and urea (d) at three time‐points, before commencing P‐407 injections (day 0), 14 days following P‐407 administration and prior to NTS injection (day 14) and 2 weeks after the induction of ANTN (day 28). Values represent mean ± standard error (s.e.); n = 9 in the P‐407 group, n = 11 in the PBS group; P‐values using the unpaired t‐test when comparing two groups and the paired t‐test when comparing days 0 and 28 within the same group. Due to insufficient blood collection a few samples were not available at days 0 and 14.…

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  Figure 2. The hypersensitive response to accelerated nephrotoxic nephritis (ANTN) in hyper‐triglyceride‐rich lipoprotein (TGRL) mice does not appear to be complement‐mediated. (a) Representative images of glomerular C3 (top panels) and immunoglobulin (Ig)G (bottom panels) staining at day 28 in chow‐fed B6 mice treated with 10 mg poloxamer 407 (P‐407) or phosphate‐buffered saline (PBS), as shown in Fig. 1a. (scale bar = 50 μm). (b) Quantification of glomerular C3 expressed as arbitrary fluorescence units (AFU). Data shown are the mean fluorescent signal in 10 glomeruli per section. Each dot represents a mouse and horizontal bars denote the mean. P‐value calculated using the unpaired t‐test. (c) Plasma C3 levels (μg/ml) measured at the indicated time‐points. Data are presented as mean ± standard error (s.e.). P‐value by the unpaired t‐test. Due to insufficient blood collection a few samples were not available at days 0 and 14. (d) Quantification of glomerular IgG expressed as AFU. Each dot represents the mean fluorescent signal in 10 glomeruli per section from each mouse. Horizontal bars denote the mean, unpaired t‐test. **P < 0·01; ***P < 0·001; n.s. = not significant.

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  Figure 3. Cytokine and chemokine levels in hyper‐triglyceride‐rich lipoprotein (TGRL) mice following accelerated nephrotoxic nephritis (ANTN). Plasma levels measured at day 28 in chow‐fed B6 mice injected with either 10 mg poloxamer 407 (P‐407) or phosphate‐buffered saline (PBS), as Fig. 1a, n = 5 in each group. Each dot represents a mouse; horizontal bars indicate the median; Mann–Whitney U‐test. *P < 0·05; **P < 0·01; n.s. = not significant.

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  Figure 4. No enhancement of renal damage in diet‐induced hypercholesterolemic Ldlr–/– animals following accelerated nephrotoxic nephritis (ANTN). (a) Schematic representation of the experiment conducted in Ldlr–/– and B6 female mice (n = 7–11 in each group) fed a high‐fat (HF) diet. Nine days following diet modification, the mice were immunized with sheep immunoglobulin (Ig)G, followed 5 days later by intravenous (i.v.) injection of nephrotoxic serum (NTS). Blood was collected at baseline before commencement of HF diet (day 0), after 2 weeks of diet modification and before NTS injection (day 14), and 2 weeks following NTS injection (day 28). Plasma levels of triglycerides (TGs) (b), cholesterol (CHOL) (c) and urea (d) measured at the indicated time‐points. Urea levels were not available for one mouse in each group at day 0. (b–d) Data are presented as mean ± standard error (s.e.); P‐values calculated using the unpaired t‐test. Haematuria (e) and proteinuria (f) assessed by urine dipstick at day 28. Not all urine samples were available for the analysis. (g) Glomerular cellularity score (0–4) assessed on periodic acid‐Schiff (PAS)‐stained renal tissue in a blinded fashion. (e–g) Each symbol…

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  Figure 5. Cytokine and chemokine levels in high‐fat (HF)‐fed Ldlr–/– mice following accelerated nephrotoxic nephritis (ANTN). Plasma levels measured at day 28 in Ldl–/‐‐ and B6 female fed HF diet. Each dot represents a mouse; horizontal bars indicate the median; Mann–Whitney U‐test; n = 5/group. *P < 0·05, **P < 0·01; n.s. = not significant.