Structural Changes in Rat Hepatocyte Nucleolus under Nucleolar Stress Caused by Hypothermia

Structural changes in rat hepatocyte nucleoli were studied during deep hypothermia simulated by immersion in water at 5 °C for 40 min (ambient air temperature 7°C). In comparison with the control, phenomena of nucleolar stress occurred in rats during hypothermia: the number of fibrillar centers (FC) per nucleus (by 1.7 times) and per nucleolus (by 1.6 times), nucleolonemal nucleoli per nucleus (by 2.8 times), and t he relative content of nucleolonemal nucleoli per nucleus (by 2.6 times) significantly decreased (p=0.0000001); the number of FC per nucleolonemal nucleolus also decreased by 1.4 times (p=0.01). In the hepatocyte nuclei, we observed an increase in the relative content of transitional type nucleoli per nucleus (by 1.3 times;p=0.01), the number of FC per transitional type nucleolus (by 1.4 times;p=0.003), the content of free FC per nucleus (by 3 times;p=0.00004), and the percentage of free FC per nucleus (by 3.5 times;p=0.00004). These changes can be considered as compensatory and adaptive reactions, and transitional type nucleoli can be attributed to the"reserve" nucleolar pool.

Source: Bulletin of Experimental Biology and Medicine - March 16, 2024 Category: Biology Source Type: research