Effects of bone marrow mesenchymal stem cell transplantation on collagen remodeling in rabbits following acute myocardial infarction

Xiaoyun QI; Guanlin YANG; Yan CHEN; Jifeng SUI; Wenjing BAO; Zhe ZHANG

ABSTRACT

BACKGROUND:

Stem cell transplantation can significantly improve heart function foUowing myocardial infarction. This is correlated with the differentiation of stem cells into cardiomyocytes and promotion effect on angiogenesis. Paracrine and ventricular reconstruction inhibition (especially extracallular collagen reconstruction) have important effects on improving heart function.

OBJECTIVE:

To investigate the effects of bone marrow mesenchymal stem cell (BMSC) transplantation on coUagen remodeling after acute myocardial infarction in rabbits.DESIGN, TIME AND

SETTING:

The randomized controlled animal study was performed at the Laboratory of Acupuncture and Electrophysiology of Liaoning University of Traditional Chinese Medicine from June to August 2007.MATERIALS A total of 57 healthy Japanese rabbits were purchased from Experimental Animal Center, Uaoning University of Traditional Chinese Medicine.

METHODS:

BMSCs were acquired from the bone marrow of two rabbits, and marked with BrdU before transplantation. Ten rabbits served as a normal group. Forty-five rabbits were used to establish the left ventricular infarct by ligation of the left coronary artery. Thirty success models of myocardial infarction were randomly divided into 3 groups (n=10)" model, saline and call transplantation groups. Following 7 days of myocardial infarction, rabbit models in the cell transplantation group were injected in the ear vein with 1 mL of BMSCs (2x106 cells). Rabbits in the saline group were infused with 1 mL of saline. The culture was performed for 5 weeks.MAIN OUTCOME

MEASURES:

Fibrous structure of myocardial stroma was observed, and collagen volume fraction was measured by Masson Trichrome staining. The ratio of type Ⅰ and Ⅲ collagen was determined by immunohistochemistry.

RESULTS:

BrdU-positive BMSCs could be seen in the cell transplantation group. After myocardial infarction, a few collagen fibers was confluent in or surrounding the infarct area, arranged orderly in the cell transplantation group. Collagen fiber plaque-shaped confluence was significant, and arranged disorderly in the model and saline groups. At 5 weeks following myocardial infarction, compared with the normal group, collagen volume fraction was significantly decreased in and surrounding the infarct region (P < 0.05), and the ratio of type Ⅰ and Ⅲ collagen was increased significantly in the model group (P < 0.05).Compared with the model group, collagen volume fraction and the ratio of type Ⅰ and Ⅲ collagen were significantly decreased (P< 0.05).

CONCLUSION:

BMSCs could survive in infarct heart. BMSCs transplantation could reduce collage volume and improve collage ratio and had beneficial effects on collage remodeling processes after acute myocardial infarction.