Serum biomarker changes of type I collagen fragments in diet-induced obesity rat during cardiac interstitial remodeling

Abstract

Objective: The obesity-prone rat model has been used to study mechanisms responsible for obesity-related abnormalities in blood pressure, cardiac function, but the mechanism of this model that exhibits cardiac interstitial remodeling has not been cleared. This study investigated the serum biomarker carboxy-terminal propeptide of type I procollagen (PICP) and type I collagen telopeptide (ICTP) changes and whether these serum biomarkers related with insulin resistance index (HOMA-IR). Methods: Male Wistar rats were fed a control diet or a high fat and high fructose diet for 12 weeks, then given telmisartan (8 mg/kg/d) for 12 weeks, assessed PICP/ICTP by enzyme linked immunosorbent assay (ELISA). Results: Obesity rats were significantly heavier and had greater body fat compared with controls, but blood pressure, heart rate and directly measured heart weight didn't differ among groups. The concentration of plasma PICP in obesity rats was significantly higher than those in control respectively (P<0.05), PICP is positively correlated with HOMA-IR (r=0.447, P<0.05). The concentration of plasma PICP in telmisartan rats was significantly lower than those in obesity. The concentration of plasma ICTP in obesity rats was significantly higher than those in control respectively (P<0.05), ICTP is negatively correlated with HOMA-IR (r=−0.47, P<0.01). Conclusion: These results suggested that the degradation of type I collagen of heart decrease and the synthesis of type I collagen of heart increase, and this change correlated to the degree of insulin resistance. Insulin resistance may be part of the mechanism of cardiac interstitial remodeling in the diet-induced obesity rat.