Abstract: To evaluate the influence of volume and pressure overload on rat right ventricle remodeling, we developed a special model which connect the arteria carotis communnis and venae jugularis externa by using a special technique, which result in volume and pressure overload. We investigated the histological changes and the fibrosis characteristics were studied by RTPCR. Methods: Four experimental groups and four controlled groups were carried out, each had 10 weigh/sex matched Wistar rats. The experimental groups undergone the surgery which we mentioned above. After 1, 2, 4 and 8 weeks later, the right ventricle pressure and body weight were observed and the ratios of right ventricle/(left ventricle + septum) ［R/(L+S)］、 right ventricle/body weight (RVmg/BWg) were calculated. We performed RTPCR to examine the fibrosis changes while the right ventricle remodeling. The controlled groups undergone the same operation except connecting the arteria carotis communnis and venae jugularis externa of the right side, and were fed on the same conditions. Results: The right ventricle pressure was elevated and maintained relatively stable at the 1st, 2nd, 4th and 8th week after surgery. ①There′s increment of (RV mg/BW g) after 8weeks, (0.64±0.05 vs 0.43±0.03， P＜0.01); At the same time, the ［R/(L+S)］ increased too(0.36±0.04 vs 0.21±0.02，　P＜0.05); ②No heart failure occurred in all groups. The changes of mRNA expression of type Ⅰ collagen、type Ⅲ collagen were increased at 2nd week(type Ⅰ collagen： 0.93±0.18 vs 0.79±0.07，　P＜0.05；　type Ⅲ collagen：　0.43±0.07 vs 0.36±0.07，　P＜0.05. average of densitometry). No difference existed between the experimental groups and controlled groups at the 1st, 4th and 8th week. And the expression of fibronectin Ⅰ mRNA was increased at the 1st week(0.26±0.06 vs 0.20±0.05，　P＜0.05). At the 2nd week, it returned to controlled group level. Conclusions: ①Volume and pressure overload can cause myocardial remodeling in the rat right ventricle, include the myocyte and the interstitial connective tissue. Such changes should be related to the duration and right ventricle pressure； ② The interstitial connective tissue also changed in the earlier stage, include the type Ⅰ collagen、 type Ⅲ collagen and fibronectin Ⅰ.

Key words: Rats, Wistar, Pressure, Ventricle remodeling, Collagen, Fibronectin, Fibrosis