Investigation of the Effects of Lipopolysaccharide on Vascular Development using the Chick Embryo Extraembryonic Membrane Model

The proper functioning of all body tissues depends on an effective and well-structured vascular system. Consequently, the formation of blood vessels is essential for the development of any tissue. Angiogenesis, the process by which new blood vessels develop from pre-existing ones, plays a fundamental role in maintaining health and is implicated in the pathogenesis of numerous diseases. Lipopolysaccharide (LPS) is a crucial structural component of the cell wall of Gram-negative bacteria, possessing certain pathogenic properties and being regarded as a bacterial toxin. Fourteen fertilized Ross 308 eggs, with an average weight of 51 ± 3 grams, were randomly divided into two equal groups of seven. In the first group (experiment), LPS was injected at a dose of 100 mg/kg body weight into the shell membrane, and in the second group (control), the same amount of PBS was injected. LPS was inoculated at 24, 48, and 72 hours after the start of incubation. Twenty-four hours after the last inoculation, the eggs were longitudinally opened to access the membranes. Then, the shell membrane was removed, and the evolution of the vascular network was evaluated by various image analysis software. The assessment revealed a significant reduction in vessel area, vessel length, number of vessel branches, percentage of new vessel formation areas, and vascular complexity in the experimental group compared to the control group (p < 0.05). Based on the obtained results, it was determined that the composition of LPS can have an inhibitory effect on the growth and development of the extraembryonic vascular network of chickens.