Effects of Estrogen in Comparison with Combined Estrogen and Vitamin E on the Structure of the Ascending Aorta of Senile Female Albino Rats: A Light and Scanning Electron Microscopic Study

Abstract

Aim of the Work: The present study aimed at illustrating the structural changes in senile ascending aorta and comparing the effects of combined estrogen and vitamin E and estrogen therapy alone in improving these changes by both light and scanning electron microscopy. Material and Methods: Thirty female albino rats were used in the present work; adult rats (6 _ 7) month old and senile rats (22 - 23)- month old. The senile rats were divided into three subgroups, control group and a group that received 0.05 ml of folone by intramuscular injection (one injection/ month). The last group received combined estrogen and vitamin-E 40 IU daily by gastric intubation. Animals were anaesthetized after 10 weeks and specimens were processed for microscopic studies. Results: The ascending aorta of senile rats exhibited discontinuity of internal elastic lamina, large vacuolated foam cells in the tunica media and interrupted widely separated elastic lamellae of the tunica media. Collagen fiber deposition was noticed in the three layers. Scanning electron microscopy revealed loss of regular pattern of surface endothelium, desquamation, ulceration or focal shedding of endothelial lining. Upon administration of estrogen, internal elastic lamina appeared continuous. The elastic lamellae in the tunica media were less affected but the tunica adventitia still manifested cellular infiltration. Collagen was noticed in both the tunica intima and media. Scanning electron microscopy revealed that the surface endothelium was still rough with few blebs. Following combined estrogen and vitamin E administration, the characteristic finding was the appearance of elastic lamellae of the tunica media with no signs of separation between its layers. Collagen deposition was still prominent in some areas in the tunica media. Scanning electron microscopy revealed smooth endothelial surface with no signs of ulceration or bleb formation.