Differential effects of dihydropyridine calcium antagonists on doxorubicin-induced nephrotoxicity in rats

Area of Science:

• Nephrology
• Pharmacology
• Toxicology

Background:

• Doxorubicin (DXR) is an effective chemotherapy agent but can cause kidney damage (nephrotoxicity).
• Dihydropyridine calcium antagonists are commonly used to manage hypertension.
• The protective effects of specific calcium antagonists against DXR-induced nephrotoxicity require further investigation.

Purpose of the Study:

• To compare the protective roles of amlodipine, nifedipine, and nitrendipine against doxorubicin-induced nephrotoxicity in a rat model.
• To evaluate the biochemical, histopathological, and immunohistochemical changes associated with DXR treatment and calcium antagonist co-administration.

Main Methods:

• Male Sprague-Dawley rats were assigned to five groups: control, DXR alone, DXR + nifedipine, DXR + nitrendipine, and DXR + amlodipine.
• Kidney injury was assessed through urinary protein, serum creatinine (SCr), and blood urea nitrogen (BUN) levels.
• Oxidative stress markers, including malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), and superoxide dismutase (SOD), were measured.
• Kidney tissue was examined histopathologically, and apoptosis-related proteins (Bcl-2, Bax) were analyzed immunohistochemically.

Main Results:

• DXR administration significantly increased urinary protein, SCr, and BUN levels, indicating nephrotoxicity.
• Amlodipine co-administration effectively reversed these DXR-induced changes.
• Nifedipine and nitrendipine either showed no benefit or exacerbated DXR-induced kidney damage.
• DXR increased oxidative stress markers (MDA, NO) and decreased antioxidant markers (GSH, SOD), effects mitigated by amlodipine.
• Histopathological analysis revealed significant kidney structural damage with DXR, characterized by increased apoptosis and altered Bcl-2/Bax expression, which amlodipine ameliorated.

Conclusions:

• Amlodipine demonstrated significant protective effects against doxorubicin-induced nephrotoxicity in rats.
• Nifedipine and nitrendipine did not provide protection and, in some cases, worsened kidney injury.
• These findings suggest amlodipine may be a beneficial adjunct therapy in patients undergoing doxorubicin treatment to mitigate nephrotoxicity.