Effects of Cannabidiol (CBD) on Doxorubicin-Induced Anxiety and Depression-like Behaviors and mRNA Expression of Inflammatory Markers in Rats

Abstract

Background: Post-treatment side effects of chemotherapy can include cognitive deficits commonly known as Chemo-brain. The treatment of patients with Doxorubicin (DOX), one of the most widely used chemotherapeutic drugs in the treatment of cancer, can induce depression, anxiety, and impaired cognitive function. Cannabidiol (CBD) is a non-psychoactive component of Cannabis sativa that has been identified as a possible therapeutic agent against many neurodegenerative disorders, including traumatic brain injury, spinal cord injury, Tau-protein-induced neurodegeneration, and neuropathic pain. Therefore, this study aimed to assess whether oral CBD administration could reduce DOX-induced anxiety and depression-like behaviors and alter the expression of mRNA associated with neuroinflammation. Methods: Female Long Evans Hooded rats received intraperitoneal injections of DOX (6 mg/kg) or the vehicle (0.9% saline) once a week for four weeks, followed by oral administration of CBD (10 mg/kg) three times a week for the same period. Results: CBD was significantly protective against DOX-induced anxiety and depression-like behaviors, as measured by several behavioral tests. Furthermore, CBD improved DOX-induced alterations in the gene expression of biomarkers of neuroinflammation in the hippocampus and prefrontal cortex. Conclusions: This provides insights into future studies on possible mechanisms by which DOX-induced cognitive dysfunction could be alleviated by CBD.

Keywords: cannabidiol; chemo-brain; cognitive deficits; doxorubicin; neuroinflammation.

Figure 1

Experimental timeline. After acclimatization, rats were injected intraperitoneally with DOX (6 mg/kg) or the vehicle. Beginning the day after injection, rats received either CBD (10 mg/kg in MCT oil; 4 consecutive days each week; oral route) or MCT oil alone (0.5 mL/kg) for 4 consecutive weeks. Behavioral tests were conducted serially over 4 weeks (in the order shown from top to bottom), beginning one week after experimental treatments concluded. At the end of the study, rats were euthanized, and brain tissue samples were collected for qPCR assay at week 10. DOX—doxorubicin; CBD—Cannabidiol; MCT—Medium-Chain Triglyceride; IP—intraperitoneal; EPM—Elevated Plus Maze; OFT—Open Field Test; NOR—Novel Object Recognition; MBT—Marble Burying Test; SPT—Sucrose Preference Test.

Figure 2

Effects of CBD and DOX on (a) body weight (n = 4/group), (b) food consumption (n = 4/group). Rats in all the treatment groups were monitored to study the effect on body weight and food intake over the entire study period. All the data points were collected at baseline and 1 week after treatment. Two-way repeated measures ANOVA with Tukey’s post hoc test was used to analyze the data and are presented as means ± SEM, DOX, doxorubicin; CBD, Cannabidiol.

Figure 3

CBD treatment significantly alleviated anxiety-like behaviors induced by DOX treatment in EPM. (a) Time spent in closed arms. (b) Time spent in open arms. Data are presented as mean ± SEM (n = 4). * p ≤ 0.05, ** p ≤ 0.01, one-way ANOVA followed by Tukey’s post hoc test). DOX—doxorubicin; CBD—Cannabidiol.

Figure 4

Effects of CBD and DOX treatment on Open Field Test. (a) Time spent in center. (b) Time spent in corner. Data are presented as mean ± SEM (n = 4; one-way ANOVA followed by Tukey’s post hoc test). DOX—doxorubicin; CBD—Cannabidiol.

Figure 5

Anxiolytic effect of CBD against DOX treatment in Marble Burying Test (n = 4). Number of marbles buried was counted for each animal after 30 min of test session. Data are displayed as mean ± SEM (n = 4). ** p ≤ 0.01, *** p ≤ 0.001, (one-way ANOVA followed by Tukey’s post hoc test). DOX—doxorubicin; CBD—Cannabidiol. Some error bars may be too small to see on the chart.

Figure 6

The percentage of preference for a novel object during the Novel Object Recognition test. The percentage of novel object preference was calculated as novel object exploration time/Total (novel + familiar) object exploration time × 100%. Data are presented as mean ± SEM (n = 4). * p ≤ 0.05 (one-way ANOVA followed by Tukey’s post hoc test). DOX—doxorubicin; CBD—Cannabidiol. Some error bars may be too small to see on the chart.

Figure 7

Effects of CBD on DOX-induced sucrose preference deficit. Percentage of sucrose preference (sucrose intake/total intake × 100). Data are displayed as mean ± SEM (n = 4). * p ≤ 0.05, one-way ANOVA followed by Tukey’s post hoc test). DOX—doxorubicin; CBD—Cannabidiol.

Figure 8

CBD suppressed neuroinflammatory response in the prefrontal cortex of DOX-injected rats. Quantification of gene expression by qPCR. Relative mRNA expressions of Tnf (a), Nfkb1 (b), Il1b (c), Il6 (d), Tgfb1 (e), Il10 (f), GFAP (g), Aif1 (h) were measured. Real-time PCR results were standardized against Actb, and data are presented as mean ± SEM. n = 4/group; *, **, ***: significant differences observed for p ≤ 0.05, p ≤ 0.01, and p ≤ 0.001, respectively (one-way ANOVA followed by Tukey’s post hoc test). DOX—doxorubicin; CBD—Cannabidiol; qPCR—real-time polymerase chain reaction; Tnf—tumor necrosis factor; Nfkb1—Nuclear factor kappa-light-chain-enhancer of activated B cells Subunit 1; Il1b—Interleukin beta 1; Il6—Interleukin 6; Tgfb1—Transforming growth factor beta 1; Il10—Interleukin 10; Aif1—Allograft inflammatory factor 1; Gfap—glial fibrillary acidic protein; Actb—beta actin. Some error bars may be too small to see on the chart.

Figure 8

CBD suppressed neuroinflammatory response in the prefrontal cortex of DOX-injected rats. Quantification of gene expression by qPCR. Relative mRNA expressions of Tnf (a), Nfkb1 (b), Il1b (c), Il6 (d), Tgfb1 (e), Il10 (f), GFAP (g), Aif1 (h) were measured. Real-time PCR results were standardized against Actb, and data are presented as mean ± SEM. n = 4/group; *, **, ***: significant differences observed for p ≤ 0.05, p ≤ 0.01, and p ≤ 0.001, respectively (one-way ANOVA followed by Tukey’s post hoc test). DOX—doxorubicin; CBD—Cannabidiol; qPCR—real-time polymerase chain reaction; Tnf—tumor necrosis factor; Nfkb1—Nuclear factor kappa-light-chain-enhancer of activated B cells Subunit 1; Il1b—Interleukin beta 1; Il6—Interleukin 6; Tgfb1—Transforming growth factor beta 1; Il10—Interleukin 10; Aif1—Allograft inflammatory factor 1; Gfap—glial fibrillary acidic protein; Actb—beta actin. Some error bars may be too small to see on the chart.

Figure 9

CBD suppressed neuroinflammatory response in the hippocampus of DOX-injected rats. Quantification of gene expression by qPCR. Relative mRNA expressions of Tnf (a), Nfkb1 (b), Il1b (c), Il6 (d), Tgfb1 (e), Il10 (f), GFAP (g), Aif1 (h) were measured. Real-time PCR results were standardized against Actb, and data are presented as mean ± SEM. n = 4/group; *, **, ***, ****: significant differences observed for p ≤ 0.05, p ≤ 0.01, p ≤ 0.001, p ≤ 0.0001 respectively (one-way ANOVA followed by Tukey’s post hoc test). DOX—doxorubicin; CBD—Cannabidiol; qPCR—real-time polymerase chain reaction; Tnf—tumor necrosis factor; Nfkb1—Nuclear factor kappa-light-chain-enhancer of activated B cells Subunit 1; Il1b—Interleukin beta 1; Il6—Interleukin 6; Tgfb1—Transforming growth factor beta 1; Il10—Interleukin 10; Aif1—Allograft inflammatory factor 1; Gfap—glial fibrillary acidic protein; Actb—beta actin. Some error bars may be too small to see on the chart.

Figure 9

CBD suppressed neuroinflammatory response in the hippocampus of DOX-injected rats. Quantification of gene expression by qPCR. Relative mRNA expressions of Tnf (a), Nfkb1 (b), Il1b (c), Il6 (d), Tgfb1 (e), Il10 (f), GFAP (g), Aif1 (h) were measured. Real-time PCR results were standardized against Actb, and data are presented as mean ± SEM. n = 4/group; *, **, ***, ****: significant differences observed for p ≤ 0.05, p ≤ 0.01, p ≤ 0.001, p ≤ 0.0001 respectively (one-way ANOVA followed by Tukey’s post hoc test). DOX—doxorubicin; CBD—Cannabidiol; qPCR—real-time polymerase chain reaction; Tnf—tumor necrosis factor; Nfkb1—Nuclear factor kappa-light-chain-enhancer of activated B cells Subunit 1; Il1b—Interleukin beta 1; Il6—Interleukin 6; Tgfb1—Transforming growth factor beta 1; Il10—Interleukin 10; Aif1—Allograft inflammatory factor 1; Gfap—glial fibrillary acidic protein; Actb—beta actin. Some error bars may be too small to see on the chart.