[GW28-e0558]

Inhibition of TRPA1 prevents Adriamycin-induced acute cardiotoxicity through suppression of oxidative stress and inflammation responses

Zhen Wang Menglong Wang Jianfang Liu Jing Ye Yao Xu Huimin Jiang Jun Wan
Renmin Hospital of Wuhan University

Objectives: To investigate the potential role of TRPA1 in the development of doxorubicin-induced acute cardiotoxicity
Methods: 80 experimental male C57BL/6J mice were randomly divided into four groups: sham + vehicle (n=20), sham + HC-030031(HC) (n=20), ADR + vehicle (n=20), and ADR + HC-030031(HC) (n=20). HC-030031 (10mg/kg, i.g.), a selective TRPA1 blocker, was administered from 0 to 10 d. Acute ADR cardiotoxicity was induced by a single intraperitoneal injection of 20 mg/kg DOX in mice on the 5th day. Cardiotoxicity was assessed by measuring the levels of various antioxidant parameters in the heart and the release of marker enzymes in the serum. Cardiac function was assessed 5 days after ADR exposure through echocardiography. Thereafter, the hearts were harvested and weighed. Heart sections were evaluated for pathological lesions. The RT-PCR, western blotting, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were performed to check for ADRinduced damages.
Results: The results demonstrated that ADR treatment enhanced myocardial TRPA1 mRNA andprotein levels. Next, we calculated the and body weight (BW) and heart weight (HW) of mice in each group. Compared to control mice, mice treated with ADR showed a decreased BW and HW. The HC alone group had similar BW and HW to those of the control animals. Meanwhile, HC treatment did not alter the BW and HW in ADR-treated animals. Interestingly, there was no differences in the HW/BW on day 10 among the 4 groups. Further, ejection fraction (EF) and fractional shortening (FS) were also reduced in the ADR+HC group, but the level was significantly higher than that observed in the ADR-only group at day 10. Histological examinations also revealed increased vacuolar and myofibrillar disorganization in mice with ADR treatment, while they were ameliorated in the ADR+HC group. Additionally, the significant increased biomarkers of cardiac injury including CK-MB, LDH, ALT and AST were further detected after ADR administration. Interestingly, administration of HC decreased the level of serum enzyme obviously, indicating the attenuated myocardial injury. Then, the administration of HC alone to mice had no effects on enzyme activities compared with control group. ADR treatment caused significant reduction in the activities of SOD and GSH as well as increase in the levels of MDA when compared with the sham groups. In addition, Treatment with HC indicated a statistically decrease in MDA levels and restored the activities of SOD and GSH antioxidant levels as compared with the ADR-treated group.
Furthermore, inhibition of TRPA1 with HC remarkable reduced the expression of pro-inflammatory cytokines, such as IL-1β, IL-6, IL-17 and TNF-α, and suppressed the downstream inflammatory cascade. TUNEL staining showed an increase in cardiomyocyte apoptosis rate in the ADR group, whereas the increased apoptosis rate was reduced by HC treatment with the ADR injection. To confirm these findings, western blot analysis was applied to assess the expression levels of the apoptosis-related proteins. The expression levels of casepase-3, caspase-9 and Bax/Bcl-2 in myocardial tissue were significantly higher in the ADR group than the other three groups. Furthermore, HC-treat decreased casepase-3 and caspase-9 as well as the ratio of Bax/Bcl-2 protein expression in ADR plus HC group
Conclusions: Inhibition of TRPA1 could prevent ADRinduced acute cardiotoxicity in mice by inhibiting oxidative stress and in?ammation.