BACKGROUND: Doxorubicin is one of the most widely used anticancer chemotherapeutic agents in small animal practice. The use of doxorubicin can cause cardiotoxicity, hepatotoxicity, neurotoxicity, and nephrotoxicity. OBJECTIVES: This study was carried out to evaluate the effects of ascorbic acid on doxorubicin hepatotoxicity in mice. METHODS: Twenty-four Balb/c mice were randomly divided into four groups. Group one received normal saline, group two received 100 mg/kg ascorbic acid, group three received 8 mg/kg doxorubicin and group four received ascorbic acid and doxorubicin intraperitoneally, with the same doses of groups 2 and 3. Twenty-one days after injection, the mice were euthanized. The activities of ALP, ALT, AST enzymes and total bilirubin levels in the serum samples were measured. Liver samples were evaluated histopathologically. RESULTS: The activities of ALP, ALT, AST, and total bilirubin levels and histopathologic scores of hepatotoxicity were significantly lower in the group that received ascorbic acid + doxorubicin in comparison to those of the doxorubicin group. CONCLUSIONS: Ascorbic acid may be useful in the prevention of doxorubicin hepatotoxicity in mice. Further studies are recommended for evaluation of the use of ascorbic acid in small animals.

BACKGROUND: Breast cancer is the most commonly diagnosed cancer in women. One in eight women will be diagnosed with breast cancer in their lifetime. Chemotherapy works on active cells. Active cells are cells that are growing and dividing into more of the same type of cell. Cancer cells are active, but so are some healthy cells. Also, scientists work constantly to develop ways of providing treatment with fewer chemotherapy side effects. Objectives: The aim of this study was antitumor effect of simultaneous low-intensity, 150 kHz ultrasound, in combination with the reduced dose of anticancer drug Doxorubicin (DOX) on breast adenocarcinoma using murine model (BALB/c). Methods: Twenty-five female BALB/c mice were used in this study. The tumor was implanted under the breast skin of mice. Mice were divided into five groups, namely control, sham, drug (IV injected of 2 mg/kg of DOX), drug (IV injected of 1 mg/kg of DOX) + US (150 kHz for 15 minutes) and exposure to ultrasound (150 kHz for 15 minutes) alone. The data were analyzed employing ANOVA using SPSS software V.13 and complementary test of Tooki was done. Results: It was shown that, after injection of DOX, exposure to ultrasound at 150 kHz the necrotic spaces in adenocarcinoma tumors compared to control and sham groups have meaningful variance (p<0.001). There was also a significant difference (the bigger the necrotic spaces) between the drug+US group and drug treated group (p<0.05), It should be mentioned that the dose of DOX in drug+US group was reduced to 1mg/kg. Conclusions: The co-administration of DOX and low-intensity ultrasound provided a more effective treatment than the drug alone in murine adenocarcinoma breast cancer. The combined treatment appeared to produce synergistic effects that could prove potentially useful in reducing the side effects of DOX by lowering the required effective dose of the drug while increasing the efficiency of the therapy as a whole.

Introduction: Due to the high heterogeneity of canine lymphoma, the aim of the present study was to test in vitro the chemosensitivity of canine high-grade primary lymphoma cells to various cytostatic drugs commonly used to treat dogs: 4-HO-cyclophosphamide, doxorubicin, dexamethasone, prednisolone, vincristine, etoposide, chlorambucil, lomustine, and cytosine arabinoside. Material and Methods: To determine the cell viability and drug ability to induce apoptosis two different tests were used: an MTT assay and annexin V/propidium iodide staining. Results: Both in vitro tests were found to be useful tools. Significant differences in the sensitivity, depending on the drug type, between B-, T- and mixed/null-type lymphoma cells were found for the majority of the tested drugs. B-type cells were the most sensitive in vitro, whereas T-type cells seemed to be the most resistant. Doxorubicin, chlorambucil, etoposide, and vincristine most strongly reduced the cell viability and induced apoptosis. Conclusion: In vitro assays, such as the MTT test and especially the annexin V/PI assay, may be useful tools for predicting a response to the treatment of high-grade lymphoma in dogs or improving the treatment outcomes in individual animals.

The proposed advantages of intra-arterial chemotherapy (IAC) are based on the premises of local dose escalation to the tumor and reduced availability of systemic drugs. There is a lack of objective pharmacokinetic data to confirm the advantage of IAC in dogs with naturally occurring urogenital tumors. The objective of this study was to determine if IAC administration in urogenital tumors would result in decreased systemic drug exposure when compared to intravenous routes. Twenty-two dogs with naturally occurring urogenital tumors were enrolled in this prospective case-controlled study. Mitoxantrone, doxorubicin, or carboplatin were administered by IAC and intravenous routes [intravenous awake (intravenous chemotherapy - IVC) and under general anesthesia (IVGAC)] 3 weeks apart. Serum assays were used to determine the extent of systemic drug exposure. Dose-normalized peak systemic serum concentration (Cmax) and area under the serum drug concentration-time curve (AUC) were used to quantify systemic exposure. A total of 26 mitoxantrone treatments were administered to 10 dogs. While there was no significant difference in Cmax, the AUC was significantly lower after IAC compared with IVGAC. Ten doxorubicin treatments were administered to 5 dogs. There were no significant differences in Cmax or AUC. A total of 14 carboplatin treatments were administered to 7 dogs. The Cmax was significantly lower for IAC compared to IVC, while the AUC values were equivocal. This study demonstrates certain lower serum values may be achieved after IAC delivery of carboplatin and mitoxantrone. These chemotherapy agents may have a preferred pharmacological profile for regional chemotherapy delivery in dogs with urogenital tumors.

The present study was designed to evaluate the probable ameliorative effect of dandelion extract against doxorubicin hemato-cardiotoxicity. To accomplish this study, four groups of male albino rats (n=7) were used as follow, Group I: served as a control group, Group II: received dandelion extract (200 mg/ kg), Group III: received doxorubicin (2.5 mg/kg) and Group IV: received dandelion extract and doxorubicin identically to groups II and III. Doxorubicin was administrated 3times/week for two consecutive weeks, while dandelion extract was administrated daily for two consecutive weeks before doxorubicin administration and continued during doxorubicin treatment. The results illuminated that, administration of doxorubicin has a deleterious effect on both of blood cellular components and cardiac tissues, which was indicated by significant pancytopenia (decrease in all blood cell types), elevated serum cardiac enzymes activity (CK-MB and LDH), increased serum level of cardiacrelated proteins (troponin I, atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) with a depletion of cardiac tissues antioxidant (GSH, and SOD enzyme) and elevated lipid peroxide (MDA) level in this tissues. Coadministration of dandelion extract with doxorubicin significantly alleviated its hemato-cardiotoxic effect which was reflected positively on hematobiochemical changes and cardiac histopathological alterations.

OBJECTIVE To assess the in vitro effects of doxorubicin and tetrathiomolybdate (TM) on cells from a canine hemangiosarcoma cell line. SAMPLE Cultured cells from the canine hemangiosarcoma–derived cell line DEN-HSA. PROCEDURES Cells were treated with TM (0 to 1.5μM), doxorubicin (0 to 5μM), or both with or without 24 hours of pretreatment with ascorbic acid (750μM). Degree of cellular cytotoxicity was measured with a colorimetric assay. Long-term growth inhibition was assessed with a 10-day colony-formation assay. Induction of apoptosis was quantitated by fluorometric assessment of caspase-3 and −7 activation. Formation of reactive oxygen species (ROS) was also detected fluorometrically. RESULTS Exposure of cells to the combination of TM and doxorubicin resulted in a greater decrease in proliferation and clonogenic survival rates than exposure to each drug alone. This treatment combination increased ROS formation and apoptosis to a greater extent than did doxorubicin or TM alone. Ascorbic acid inhibited both TM-induced ROS formation and apoptosis. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the enhancement in cytotoxic effects observed with DEN-HSA cell exposure to the combination of doxorubicin and TM was achieved through an increase in ROS production. These findings provide a rationale for a clinical trial of this treatment combination in dogs with hemangiosarcoma.

Pharmacokinetics and toxicity of a single dose of doxorubicin, at dosages of 30 mg/m2 of body surface area and 1 mg/kg of body weight, were compared in 17 dogs. Effects of doxorubicin on complete blood cell count, platelet count, and the dogs' clinical condition were evaluated for 14 days. Cluster analysis, on the basis of clinical signs of doxorubicin toxicosis at the 30-mg/m2 dosage, revealed that 6 of 7 small dogs (less than or equal to 10 kg) became ill, whereas 7 of 10 large dogs (> 10 kg) remained clinically normal. Small dogs that received doxorubicin at a dosage of 30 mg/m2 had higher peak plasma concentrations, greater area under the curve for plasma drug concentration vs time, longer drug elimination half-lives, greater volumes of distribution, and more clinical signs of toxicosis than had large dogs (P less than or equal to 0.05). Five of 9 small dogs that received doxorubicin at a dosage of 30 mg/m2 developed severe myelosuppression (< 1 X 103 granulocytes/microliter). In contrast to the toxicoses with body surface area-based dosing, myelosuppression was not induced in small dogs that received doxorubicin at a dosage of 1 mg/kg. In small and large dogs given doxorubicin at a dosage of 1 mg/kg, pharmacokinetic characteristics and clinical signs of toxicosis were similar. Mean WBC counts and granulocyte counts for all dogs were lower on day 7 with 30 mg of doxorubicin/ m2 (n = 17), compared with that for 1 mg of doxorubicin/kg (n = 14; P S 0.01). This study indicated that a body weight-based (milligram per kilogram) dosing regimen may result in more uniform therapeutic and toxic responses in dogs. Limited toxicosis was observed in dogs weighing > 10 kg treated with doxorubicin with either dosing scheme; however, differences in pharmacokinetic profiles suggested that 1 mg/kg may be an inappropriately low dosage.

A rapid, simple chemosensitivity assay, assessing tumor cell nuclear uptake of doxorubicin hydrochloride, was evaluated in 16 dogs with appendicular osteosarcoma. Doxorubicin was administered to dogs in 5 biweekly treatments, and surgical resection was performed after the second or third treatment, The chemosensitivity assay was performed on biopsy specimens from all dogs before chemotherapy. It was repeated on tissue from resected tumors, and tumors were evaluated histologically to determine the degree of necrosis resulting from chemotherapy. Disease-free and total survival time correlated significantly (P < 0.05 in both cases) with the degree of postchemotherapy necrosis of the primary tumors. Significant correlation was not apparent between the percentage of tumor cells with nuclear uptake of doxorubicin (in either biopsy or resection samples) and disease-free or total survival time. The percentage of cells with nuclear uptake of doxorubicin in surgically resected tumors correlated significantly (P < 0.05) with percentage of necrosis,

Canine erythrocytes were loaded with the antineoplastic drug doxorubicin and then treated with 0.16% glutaraldehyde. This procedure has been previously shown to slow down the efflux of doxorubicin from erythrocytes and to result in the selective targeting of the carrier erythrocytes to liver. Three dogs were treated each with 2 different schedules of IV bolus administration of doxorubicin (0.4 mg/kg of body weight): free drug and doxorubicin encapsulated in glutaraldehyde-treated erythrocytes. The 2 treatments yielded consistent differences in the plasma pharmacokinetic properties of doxorubicin and of its only metabolite, doxorubicinol. A triphasic exponential decay of doxorubicin plasma concentrations was observed on injection of the free drug. Conversely, in the case of erythrocyte-encapsulated doxorubicin, 4 phases of plasma concentrations of doxorubicin were found. The plasma concentrations of doxorubicinol, after a steady increase during the first hour, followed patterns of decay comparable to those of the parent drug. On the basis of the kinetic variables calculated with the 2 administration schedules, area under curve concentrations of plasma doxorubicin were 136 microgram.h/L (free infusion) and 734 microgram.h/L erythrocyte-encapsulated drug). Significant alterations of hematologic and hematochemical factors were not observed in the 3 dogs during and after the 2 treatments. On the basis of our findings, doxorubicin-loaded and glutaraldehyde-treated erythrocytes may potentially be used in the treatment of systemic and hepatic tumors in dogs.

Natural killer (NK) cell activity and function were determined for 11 untreated and treated dogs with lymphoma. Concurrent chromium release and single cell binding assays, methods used to measure overall cytotoxic activity and that from individual cells, respectively, were performed at effector-to-target cell ratios of 50:1 and 100:1, with incubation periods of 12 and 16 hours. Significant reduction was achieved in overall activity for untreated dogs, using a 16-hour incubation period and an effector-to-target ratio of 100:1 (P less than 0.05). Decreased activity (P less than 0.025) was also achieved for those dogs that were administered combination chemotherapy, consisting of such drugs cyclophosphamide, vincristine, prednisone, and doxorubicin. There was no significant difference in binding or cytotoxin activity by individual cells in the untreated or treated dogs, compared with the healthy controls. Short- or long-term treatment with glucocorticoids did not influence overall NK cell activity or individual cell cytotoxicity. The overall cytotoxic activity in untreated dogs was reduced, but these dogs had relatively normal numbers of NK cells compared with paracontrols. This suggests that a defect in recycling, or the ability to kill targets repetitively, may be involved. A similar defect was found in NK cells of dogs treated aggressively with combination chemotherapy.