Recombinant human endostatin reduces radiation-induced myocardial fibrosis in rats / 中华放射医学与防护杂志

ABSTRACT

Objective:To assess the effects of recombinant human endostatin (rh-ES) on radiation-induced myocardial fibrosis.Methods:Totally 40 SD rats were randomly divided into 4 groups, including A group as normal control, B group receiving rh-ES with a dosage of 6 mg·kg -1·d -1, in traperitoneal injection, for 14 consecutive days, C group with local heart irradiation delivered to the precordial region of rats in five fractions with a dose of 25 Gy, D group receiving rh-ES as the same as B group and local heart irradiation as C group. At 1 and 3 months after irradiation, five rats were killed under anesthesia. Mason staining was used to observe myocardial injury and fibrosis. Western blotting was used to detect the expression of TGF-β1, CTGF and COL-I in myocardium. Results:Masson staining showed that no obvious myocardial fibrosis was found in group B at 1 month and 3 months after irradiation, while collagen fibers were distributed in myocardium in groups C and D. One month after irradiation, the result of semi-quantitative analysis showed that the CVF in group A was (5.20 ±0.75)%, which was significantly lower than that in group C (10.12 ±2.17)% ( t=4.74、4.93, P<0.01) and the CVF in group D (10.32 ±1.36), and the CVF of group C was similar to that of group D ( P<0.01). Three months after irradiation, CVF in group C (13.17±2.67)% was still higher than that in group A (5.23 ±1.32)% ( t=4.49, P<0.01), but lower than that in group D (16.92 ±3.58)% ( t=3.19, P<0.05). One month after irradiation, the expression of TGF-β1 in group A was 0.441 ±0.063, lower than that in group C (0.817 ±0.079, t=5.81, P<0.01). Three months after irradiation, the expression of TGF-β1 in group A was 0.501 ±0.110, lower than that in group C (0.832 ±0.150, t=4.19, P<0.01), and the expression of TGF-β1 in group D was 1.403 ±0.133, which was significantly higher than that in group C ( t=7.24, P<0.01). Conclusions:Radiation can cause the formation of myocardial fibrosis, and recombinant human endostatin may aggravate the formation of late radiation fibrosis.