Changes in cytoplasmic chromatophily and RNA content in neurons of the cingulate cortex of rats with subhepatic cholestasis

BACKGROUND: Cholestasis refers to the stagnation of bile, leading to the release of its components into the blood, which has a toxic effect on various organs and systems, including the brain, and is accompanied by cognitive and behavioral disorders. The cingulate cortex is responsible for emotions, learning, and memory. Studies of this area of the brain will help understand the mechanisms of neuropsychiatric disorders in this pathology. Moreover, studying the cytoplasmic chromatophily of cingulate cortex neurons and the RNA content will help elucidate the morphofunctional state and severity of damage to neurons and their protein synthetic apparatus (ribosomes containing RNA).

AIM: To examine the RNA content and cytoplasmic chromatophily of neurons in the cingulate cortex of the rat brain with cholestasis.

MATERIALS AND METHODS: Neurons of the second parvocellular and fifth magnocellular layers of the anterior cingulate cortex of rats were evaluated at different times after ligation/transection of their common bile duct or sham operation (control). Histological, histochemical, morphometric, and statistical analyses were performed.

RESULTS: Structural and histochemical changes in cingulate cortical neurons increase as cholestasis worsens in rats. Moreover, the number of normochromic neurons and shadow cells and hyperchromic, hyperchromic wrinkled, hypochromic neurons, and shadow cells increased, whereas the RNA content in the remaining neurons decreased. These changes reach a maximum of 10–20 days after the transection of the common bile duct. In surviving animals, in the preserved neurons of the cingulate cortex on days 45–90 after surgery, cytoplasmic chromatophily and RNA content are gradually normalized. Disturbances in the morphofunctional state of the neurons during cholestasis begin and end quite earlier in the small-cell than in the large-cell layer of the cingulate cortex.

CONCLUSION: As cholestasis increases among the neurons of the rat cingulate cortex, the number of normochromic cells decreases, whereas the number of neurons with changes in cytoplasmic chromatophily and reduction in the RNA content increases. This indicates severe morphofunctional disorders of neurons and their protein-synthesizing capabilities. As cholestasis is eliminated, the studied parameters gradually normalized in the surviving neurons, which confirms the high adaptive capabilities of rat brain neurons.