Relationship between the density of degenerated neurons in the carotid body and changes in blood pH.

Abstract

Background and aim: The carotid artery is the main artery supplying blood to the brain. Carotid bodies (CB), located at the bifurcation of the carotid artery, regulate blood pH. This study aimed to assess the changes in CB-related pH levels following degeneration induced by ligation of both common carotid arteries (CCA).

Materials and methods: We included 23 adult male New Zealand rabbits in the study. The animals were divided into three groups: a control group (n = 5), a sham group (saline injection, n = 5), and a study group subjected to bilateral CCA ligation (n = 13). pH levels and cardiac rhythms were monitored before, during, and after the procedure at two-day intervals over three weeks. Additionally, we quantified both healthy and degenerated neuron densities in the CB.

Results: Initial pH levels were as follows: control group (7.42 ± 0.039), sham (7.39 ± 0.059), and study group (7.35 ± 0 .12). Prior to euthanasia, pH levels were the following: control (7.40 ± 0.029), sham (7.42 ± 0.041), and study (7.39 ± 0.12). The density of degenerated neurons in the CB was as follows: control (11 ± 4/mm³), sham (394 ± 74/mm³), and study (1363 ± 347/mm³). Statistical analysis showed the following significant differences: control vs. sham (p < 0.001), sham vs. study (p < 0.0005), and control vs. study (p < 0.000001).

Conclusions: Increased degenerated neuron density in CB leads to reduced blood pH following CCA ligation due to acute ischemia of CB. Timely pH normalization occurs as vertebrobasilar reverse blood flow supplies CB, reversing neurodegeneration and normalizing pH.