[Improvement in cardiac morphology and function in young rats with dilated cardiomyopathy by recombinant human growth hormone].

Objective: To investigate the effects of recombinant human growth hormone (rhGH) on the morphology and function of the left cardiac ventricle in young rats with dilated cardiomyopathy (DCM), and to evaluate the efficacy and safety of rhGH in the treatment of DCM.

Methods: Sixty male Sprague-Dawley rats were randomly and equally assigned to control group, DCM group, and rhGH group. Furazolidone (0.25 mg/g) was given by gavage for 12 weeks to prepare the DCM model. Rats in the rhGH group received an intraperitoneal injection of rhGH (0.15 U/kg) once per day for 12 weeks, while rats in the DCM group received an equal volume of normal saline instead. Rats in the control group did not receive any treatment. Cardiac indices, serum biochemical parameters, hemodynamic indices, cardiac histopathological changes, and levels of myocardial collagen fibrils in each group were determined using Doppler echocardiography, enzyme-linked immunosorbent assay, multi-channel physiological recorder, light and electron microscopy, and picrosirius red staining plus polarization microscopy, respectively.

Results: Compared with the control group, rats in the DCM group had significantly increased cardiac chamber size, significantly reduced ventricular wall thickness, and significantly decreased fractional shortening (FS) and ejection fraction (EF) (P<0.05). Rats in the rhGH group had significantly improved cardiac chamber size, ventricular wall thickness, FS, and EF compared with the DCM group (P<0.05). Those indices in the rhGH group were similar to those in the control group (P>0.05). There were significant differences in serum biochemical parameters and hemodynamic indices between the DCM and control groups (P<0.05). Compared with the DCM group, the rhGH group had significantly improved serum biochemical parameters and hemodynamic indices (P<0.05). Those indices in the rhGH group were similar to those in the control group (P>0.05), except for the levels of insulin-like growth factor-1 and insulin-like growth factor-binding protein-3. The DCM group had a significantly higher collagen type I/collagen type III (Col I/Col III) ratio in the myocardium than the control group (P<0.05), and there was no significant difference in the Col I/Col III ratio between the control and rhGH groups (P>0.05).

Conclusions: rhGH plays a certain role in improvement in the morphology and function of the left cardiac ventricle in young rats with DCM.