Doxorubicin is a widely used anticancer drug whose efficacy is limited due to its cardiotoxicity. There is no ideal cardioprotection available against doxorubicin-induced cardiotoxicity. This study aimed to investigate the anticipated cardioprotective potential of metformin and dapagliflozin against doxorubicin-induced acute cardiotoxicity in Wistar rats. At the beginning of the experiment, cardiac screening of experimental animals was done by recording an electrocardiogram (ECG) before allocating them into the groups. Thereafter, a total of thirty healthy adult Wistar rats (150-200 g) were randomly divided into five groups (n = 6) and treated for eight days as follows: group I (normal control), group II (doxorubicin control), group III (metformin 250 mg/kg/day), group IV (metformin 180 mg/kg/day), and group V (dapagliflozin 0.9 mg/kg/day). On the 7th day of the treatment phase, doxorubicin 20 mg/kg was administered intraperitoneal to groups II, III, IV, and V. On the 9th day (immediately after 48 h of doxorubicin administration), blood was collected from anesthetized animals for glucose, lipid profile, CK-MB & AST estimation, and ECG was recorded. Later, animals were sacrificed, and the heart was dissected for histopathological examination. We found that compared to normal control rats, CK-MB, AST, and glucose were significantly increased in doxorubicin control rats. There was a significant reversal of doxorubicin-induced hyperglycemia in the rats treated with metformin 250 mg/kg compared to doxorubicin control rats. Both metformin (180 mg/kg and 250 mg/kg) and dapagliflozin (0.9 mg/kg) significantly altered doxorubicin-induced ECG changes and reduced the levels of cardiac injury biomarkers CK-MB and AST compared to doxorubicin control rats. Metformin and dapagliflozin protected the cellular architecture of the myocardium from doxorubicin-induced myocardial injury. Current study revealed that both metformin and dapagliflozin at the FDA-recommended antidiabetic doses mitigated doxorubicin-induced acute cardiotoxicity in Wistar rats. The obtained data have opened the perspective to perform chronic studies and then to clinical studies to precisely consider metformin and dapagliflozin as potential chemoprotection in the combination of chemotherapy with doxorubicin to limit its cardiotoxicity, especially in patients with comorbid conditions like type II diabetes mellitus.
Conjugation of Doxorubicin (DOX) to N-(2-hydroxypropyl) methylacrylamide copolymer (HPMA) has significantly reduced the DOX-associated cardiotoxicity. However, the reports on the impact of HPMA-DOX conjugates on the cardiovascular system such as blood pressure (BP) and heart rate (HR) were in restrained animals using tail cuff and/or other methods that lacked the resolution and sensitivity. Herein, we employed radiotelemetric-spectral-echocardiography approach to further understand the in vivo cardiovascular hemodynamics and variability post administration of free DOX and HPMA-DOX. Rats implanted with radio-telemetry device were administered intravenously with DOX (5 mg/kg), HPMA-DOX (5 mg DOX equivalent/kg) and HPMA copolymer and subjected to continuous cardiovascular monitoring and echocardiography for 140 days. We found that DOX-treated rats had ruffled fur, reduced body weight (BW) and a low survival rate. Although BP and HR were normal, spectral analysis indicated that their BP and HR variabilities were reduced. All rats exhibited typical signs of cardiotoxicity at histopathology. In contrast, HPMA-DOX rats gained weight over time and survived. Although BP, HR and related variabilities were unaffected, the left ventricular end diastolic volume (EDV) of these rats, as well as of the HPMA copolymer-treated rats, was found increased at the end of observation period. Additionally, HPMA copolymer caused microscopic injury of the heart tissue. All of these suggest the necessity of caution when employing HPMA as carrier for prolonged drug delivery. The current study also indicates the potential of radiotelemetric-spectral-echocardiography approach for improved preclinical cardiovascular risk assessment of polymer-drug conjugate and other nano-sized-drug constructs.
The current study evaluated the cardioprotective activity of genistein in cases of doxorubicin-(Dox) induced cardiac toxicity and a probable mechanism underlying this protection, such as an antioxidant pathway in cardiac tissues. Animals used in this study were categorized into four groups. The first group was treated with sodium carboxymethylcellulose (0.3%; CMC-Na) solution. The second group received Dox (3.0 mg/kg, i.p.) on days 6, 12, 18, and 24. The third and fourth groups received Dox (3 mg/kg, i.p.) on days 6, 12, 18, and 24 and received protective doses of genistein (100 [group 3] and 200 [group 4] mg/kg/day, p.o.) for 30 days. Treatment with genistein significantly improved the altered cardiac function markers and oxidative stress markers. This was coupled with significant improvement in cardiac histopathological features. Genistein enhanced the Nrf2 and HO-1 expression, which showed protection against oxidative insult induced by Dox. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay showed substantial inhibition of apoptosis by genistein in myocardia. The study showed that genistein has a strong reactive oxygen species scavenging property and potentially (P ≤ .001) decreases the lipid peroxidation as well as inhibits DNA damage in cardiac toxicity induced by Dox. In conclusion, the potential antioxidant effect of genistein may be because of its modulatory effect on Nrf2/HO-1 signalling pathway and by this means exhibits cardioprotective effects from Dox-induced oxidative injury.
The antiproliferative activity of a styrylpyrone derivative (SPD) plant extract, was studied in three different human breast cancer cell lines in culture, and was compared with tamoxifen. The number of living cells was evaluated by Methylene Blue staining technique. SPD showed strong antiproliferative activity in estrogen receptor (ER) and progestin receptor (PgR) positive MCF-7 cells (EC50 = 6.30 x 10(-7) M) and receptor-negative MDA-MB-231 (EC50 = 5.62 x 10(-7) M), but it partially inhibited the high progestin receptor positive T47D cells (EC50 = 1.58 x 10(-6) M). Whereas tamoxifen, a nonsteroidal antiestrogen exhibited strong inhibition on MCF-7 cells (EC50 = 1.41 x 10(-6) M) and partial inhibition on T47D cells (EC50 = 2.5 x 10(-6) M), but did not affect the MDA-MB-231 cells in the concentration range 0.1 nM-1 microM (EC50 = 5.01 microM). At the same concentration range SPD and tamoxifen did not inhibit the proliferation of normal human liver cell line CCL 13 and normal bovine kidney MDBK; whereas adriamycin, a common chemotherapy drug for the treatment of advance cancer, caused 95% inhibition at 10(-6) M. Competitive binding studies showed SPD had no ability to inhibit the binding of [3H]estradiol and [3H]progesterone to ER and PgR, respectively but, tamoxifen exhibited affinity for ER. Therefore, it can be concluded that the antiproliferative activity of SPD was selective towards breast cancer cell lines and not mediated by ER or PgR.