Comparative effects of incretin-based therapy on doxorubicin-induced nephrotoxicity in rats: the role of SIRT1/Nrf2/NF-κB/TNF-α signaling pathways

Abstract

Introduction: Nephrotoxicity represents a major complication of using doxorubicin (DOX) in the management of several types of cancers. Increased oxidative stress and the activation of inflammatory mediators play outstanding roles in the development of DOX-induced kidney damage. This study aimed to investigate whether the two pathways of incretin-based therapy, glucagon-like peptide-1 receptor agonist (presented as semaglutide, SEM) and dipeptidyl peptidase-4 inhibitor (presented as alogliptin, ALO), differentially protect against DOX-induced nephrotoxicity in rats and to clarify the underlying molecular mechanisms. Methods: Adult male rats were divided into six groups: control (received the vehicle), DOX (20 mg/kg, single I.P. on day 8), DOX + ALO (20 mg/kg/day, P.O. for 10 days), DOX + SEM (12 μg/kg/day, S.C. for 10 days), ALO-alone, and SEM-alone groups. At the end of the study, the animals were sacrificed and their kidney functions, oxidative stress, and inflammatory markers were assessed. Kidney sections were also subjected to histopathological examinations. Results: The co-treatment with either ALO or SEM manifested an improvement in the kidney functions, as evidenced by lower serum concentrations of creatinine, urea, and cystatin C compared to the DOX group. Lower levels of MDA, higher levels of GSH, and increased SOD activity were observed in either ALO- or SEM-treated groups than those observed in the DOX group. DOX administration resulted in decreased renal expressions of sirtuin 1 (SIRT1) and Nrf2 with increased NF-κB and TNF-α expressions, and these effects were ameliorated by treatment with either ALO or SEM. Discussion: Co-treatment with either ALO or SEM showed a renoprotective effect that was mediated by their antioxidant and anti-inflammatory effects via the SIRT1/Nrf2/NF-κB/TNF-α pathway. The fact that both pathways of the incretin-based therapy demonstrate an equally positive effect in alleviating DOX-induced renal damage is equally noteworthy.

Keywords: dipeptidyl peptidase-4 inhibitor; doxorubicin; glucagon-like peptide-1; incretins; nephrotoxicity.

FIGURE 1

Experimental design.

FIGURE 2

Effect of incretin-based therapies (alogliptin and semaglutide) and doxorubicin (DOX) on the kidney index. Data are represented as mean ± SEM. * is significant compared to the control group at p <0.05. # is significant compared to the DOX group at p <0.05.

FIGURE 3

Aligned dot plots showing the effect of incretin-based therapies (alogliptin and semaglutide) on the DOX-induced renal dysfunction: (A) serum creatinine, (B) urea, and (C) cystatin C concentrations. Data are represented as mean ± SEM. * is significant compared to the control group at p <0.05, and # is significant compared to the DOX group at p <0.05.

FIGURE 4

Aligned dot plots showing the effect of DOX and incretin-based therapies (alogliptin and semaglutide) on the renal levels of MDA (A), GSH (B), and SOD (C). Data are represented as mean ± SEM. * is significant compared to the control group at p <0.05. # is significant compared to the DOX group at p <0.05.

FIGURE 5

Western blot analysis of the effect of DOX and incretin-based therapies (alogliptin and semaglutide) on the renal expression of Nrf2. Nrf2 and β-actin bands of each group are shown (A), along with the bar chart of their densitometric analysis (B). Data are represented as mean ± SEM. * is significant compared to the control group at p <0.05. # is significant compared to the DOX group at p <0.05.

FIGURE 6

Western blot analysis of the effect of DOX and incretin-based therapies (alogliptin and semaglutide) on the renal expression of SIRT1. SIRT1 and β-actin bands of each group are shown (A), along with their bar chart of their densitometric analysis (B). Data are represented as mean ± SEM. * is significant compared to the control group at p <0.05. # is significant compared to the DOX group at p <0.05.

FIGURE 7

Western blot analysis of the effect of DOX and incretin-based therapies (alogliptin and semaglutide) on the renal expression of NF-κB, showing NF-κB bands and the corresponding β-actin bands of each group (A) and the bar chart of their densitometric analysis (B). Data are represented as mean ± SEM. * is significant compared to the control group at p <0.05. # is significant compared to the DOX group at p <0.05.

FIGURE 8

Western blot analysis of the effect of DOX and incretin-based therapies (alogliptin and semaglutide) on the renal expression of TNF-α, showing TNF-α bands and the corresponding β-actin bands of each group (A) and bar chart of their densitometric analysis (B). Data are represented as mean ± SEM. * is significant compared to the control group at p <0.05. # is significant compared to the DOX group at p <0.05.

FIGURE 9

Photomicrographs of the kidney tissue sections of the control group ((Aa), X200 and (Ab), X400), alogliptin group ((Ba), X200 and (Bb), X400), and semaglutide group ((Ca), X200 and (Cb), X400), showing their normal histological structure; the DOX group ((Da), X200 and (Db), X400) shows a tubular form with necrosis with the intratubular albuminous casts (arrow) and the marked retraction of capillary tufts and the widening of Bowman’s space (red arrow). The DOX + ALO group ((Ea), X200 and (Eb), X400) shows the loss of the tubular epithelial brush border with the integrity of the basal membrane (arrow), along with the mild retraction of capillary tufts and the widening of Bowman’s space (red arrow). The DOX + SEM group ((Fa), X200, (Fb), X400) shows the intact tubular epithelial lining (arrow) and the mild thickening of Bowman’s capsule without the retraction of capillary tufts (red arrow), and the bar chart (G) represents the total damage score of each group. Data are represented as mean ± SEM. * is significant compared to the control group at p <0.05. # is significant compared to the DOX group at p <0.05.