Changes in the Vascular Tissue Protein Profile of the Diabetic Rats and the Protective Role of the Beta Blockers

Abstract

Cardiovascular complication is the main cause of mortality in diabetes mellitus. Beta blockers are groups of drugs that used in the treatment of heart disease in diabetes mellitus. The object of this study is to investigate the changes in the mass spectrometric profile of the vascular tissue of the streptozotocin induced diabetic rats and the role of beta-blockers propranolol and timolol on this profile. Vascular tissues of four groups of rats (6 in each group): control, diabetic, diabetic treated with propranolol and diabetic treated with timolol were homogenized by liquid nitrogen treatment and sonication and Matrix Assisted Laser Desorption Ionization - Time of Flight - Mass Spectrometry (MALDI-TOF-MS) spectra were obtained. The data was analyzed by Mann-Whitney U test with α = 0.05. Results demonstrated 16 peaks in all groups. The intensities of 12 peaks were altered between control and diabetic group. The intensities of two were increased, while the intensities of the rest were decreased as compared to the control. The protein(s) corresponding to these 12 peaks may be involved in the changes that take place in the diabetic vascular tissue. Among these peaks, 9 of them were changed in propranolol and/or timolol treated groups as compared to diabetes group. The levels of the six peaks for both propranolol and timolol treated groups were changed as compared to the corresponding peaks of diabetic group, the levels of the five approaching to the levels of the control. The level of another peak in the propranolol treated and two other peaks in the timolol treated groups were statistically similar to the levels of the corresponding peaks of the control. The protein(s) corresponding to these peaks may be the targets of propranolol and/or timolol in the diabetic vascular tissue of the rat and they may be involved in the protective events that take place when these drugs are administered. It will be of value to investigate the identity of these protein(s) for better understanding of the mechanism of diabetic complications and for development of novel drugs for the treatment of the complications of the disease.