Aminophylline-mediated cardiotoxicity in zebrafish

Author(s): Hui Cao, Donghua Huang, Qiuxiang Cao, Yun Deng, Xiangding Chen

Background: Cardiotoxicity is one of the major side effects leading to withdrawal of aminophylline treatment. However, the aminophylline-mediated cardiotoxicity and its underlying mechanisms remain poorly studied. Recently, zebrafish has emerged as a valuable vertebrate animal model to study drug toxicity in vivo.

Methods: Wild-type zebrafish (Danio rerio) embryos were incubated with different concentrations of aminophylline solution, followed by evaluation of their survival rate, hatching rate, malformation rate, body length and Sinus Venous-Bulbus Arteriosus (SV-BA) distance to assess the potential developmental toxicity and cardiotoxicity. In addition, embryonic heart shapes of the Tg (cmlc2: EGFP), vmhcEGFP-KI, Tg (fli1: EGFP) reporter lines were also analyzed at 48 Hours Post-Fertilization (HPF) and 72 hpf, respectively. Furthermore, in situ hybridization was used to evaluate the expression levels of heart marker genes such as cmlc2, amhc, vmhc, and regulatory factors during early heart development such as hand2, nkx2.5, gata4, and valve development-related regulatory factors such as notch1b, has2, bmp4 as well.

Results: After the aminophylline drug treatment at the concentration of 0.2 mg/mL or above, zebrafish embryos exhibited reduced heart rate and increased distance between SV-BA. In addition, blood cells appeared to accumulate in the heart area, leading to pericardial edema and other poisoning phenomena. These aminophylline drug mediated cardiotoxicities were time and dose dependent. In situ hybridization analysis revealed altered expression of the regulatory factor of heart development gene nkx2.5 and valve development-related genes including notch1b, has2, which might convey the aminophylline-mediated cardiotoxicity.

Conclusion: Aminophylline-induced cardiotoxicity may be conveyed by inhibiting the expression of genes related to myocardial differentiation and valve development.