[Preparation of vascular calcification in vivo and vascular smooth muscle cell calcification in vitro of rats].

OBJECTIVE: To investigate simple, economical, stable and efficient methods of in vivo and in vitro cardiovascular calcification models in rats.

METHODS: Rats received Vitamin D(3) (300 000 U/kg, i.m.) and nicotine (25 mg/kg, 5 mL/kg in peanut oil, p.o.) at 8 a.m. on day 1. The nicotine administration was repeated at 6 p.m. Rats in control group received an injection of normal saline (i.m.) and two gavages of medium oil. All of the rats were then allowed to recover for 4 weeks and given standard rodent chow. After the measurement of cardiac function the rats were sacrificed and the calcium content in myocardium and aorta were measured. Von Kossa staining was used to detect the deposit of calcium in myocardium and aorta. Cultured smooth muscle cell(SMC) derived from rat thoracic aorta was treated with beta-glycerophosphate for 14 days, then the calcium content and deposit were measured.

RESULTS: Compared with control group, the rats with cardiovascular calcification showed a lower body weight, The ratio of left heart to body weight, myocardial and aortic calcium content were increased respectively. Alkaline phosphatases activity in calcified myocardium and aorta were increased respectively, compared with the control. The values of animal mean blood pressure (MBP), heart rate (HR) and left ventricle end-distolic pressure (LVEDP) showed no significant alteration (P>0.05) in vitamin D3 plus nicotine (VDN) group. The values of +LV dp/dt(max) and -LV dp/dtmax were significantly lower in VDN group (P<0.05 and P<0.01, respectively). In calcified vascular smooth muscle cells(VSMCs), von Kossa staining for calcification, showed positive staining as black/brown areas within the main, large, nodular structures as shown in extracellular matrix and cytoplasma. The content of calcium, (45)Ca(2+) uptake and alkaline phosphatase (ALP) activity in calcified VSMCs were increased (all P<0.01), respectively, compared with that of the control.

CONCLUSION: These methods can be used to produce calcification models in vivo and in vitro, which save money and time and are easy to manipulate.