Ethanol has chronobiological effects, which are associated with inhibition of melatonin synthesis and secretion and disruption of the sleep-wake cycle. Ethanol is known to cause sleep fragmentation due to frequent awakenings, prolong wakefulness, and reduce the duration of the slow sleep phase. At the same time, changes in the morphology of the pineal gland under chronic exposure to ethanol remain poorly studied. Of particular interest are changes in the basic morphometric parameters of pinealocytes, because they are a marker of the functional state of the pineal gland. The aim of the study was to morphometrically study the features of morphological changes in rat pinealocytes in the physiological norm and in chronic ethanol intoxication. To achieve this goal, we used 20 laboratory male rats: a control group and an experimental group. The control group was under standard vivarium conditions. For the experimental group, alcohol intoxication was modeled by injecting a 40% ethanol solution at the rate of 12 mg/kg of body weight intragastric 4 times a day. The morphometric parameters of pinealocytes were studied on day 30 from the start of the study. According to the results of morphometric measurements, a significant increase in the parameters of light pinealocytes and a decrease in the parameters of dark cells were established. It was determined that the average values of the cytoplasm area of light pinealocytes increase by 54.55% (p<0.05), the area of the nucleus increases by 61.32% (p<0.05), and the area of the nucleolus by 32.84% (p<0.05) compared with the control group. The area of the cytoplasm of dark pinealocytes decreases by 27.2% (p<0.05), and the area of the nucleus by 37.33% (p<0.05). Changes in the ratio of light and dark pinealocytes were also noted. An increase in the number of active light cells by 8.17% was found. The detected morphometric changes indicate high functional activity of cells, which has a compensatory nature in response to apoptosis of pinealocytes.
Inhibition of hepatic regeneration in rats by acute and chronic ethanol intoxication
