Department of Physiology and Biochemistry, Gdansk University of Physical Education and Sport, Kazimierza Górskiego 1, 80-336 Gdansk, Poland.
Department of Animal and Human Physiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland.
Nutrients. 2021 Mar 14;13(3):936. doi: 10.3390/nu13030936.
(1) The study aimed to investigate whether vitamin D supplementation would positively affect rats with glucocorticoids-induced muscle atrophy as measured by skeletal muscle mass in two experimental conditions: chronic dexamethasone (DEX) administration and a model of the chronic stress response. (2) The study lasted 28 consecutive days and was performed on 45 male Wistar rats randomly divided into six groups. These included two groups treated by abdominal injection of DEX at a dose of 2 mg/kg/day supplemented with vegetable oil (DEX PL; = 7) or with vitamin D 600 IU/kg/day (DEX SUP; = 8), respectively, and a control group treated with an abdominal injection of saline (CON; = 6). In addition, there were two groups of rats chronically stressed by cold water immersion (1 hour/day in a glass box with 1-cm-deep ice/water mixture; temperature ~4 °C), which were supplemented with vegetable oil as a placebo (STR PL; = 9) or vitamin D at 600 IU/kg/day (STR SUP; = 9). The last group was of sham-stressed rats (SHM; = 6). Blood, soleus, extensor digitorum longus, gastrocnemius, tibialis anterior, and quadriceps femoris muscles were collected and weighed. The heart, liver, spleen, and thymus were removed and weighed immediately after sacrifice. The plasma corticosterone (CORT) and vitamin D metabolites were measured. (3) We found elevated CORT levels in both cold water-immersed groups; however, they did not alter body and muscle weight. Body weight and muscle loss occurred in groups with exogenously administered DEX, with the exception of the soleus muscle in rats supplemented with vitamin D. Decreased serum 25(OH)D concentrations in DEX-treated rats were observed, and the cold water immersion did not affect vitamin D levels. (4) Our results indicate that DEX-induced muscle loss was abolished in rats supplemented with vitamin D, especially in the soleus muscle.
（1）本研究旨在探讨维生素 D 补充剂是否会对两种实验条件下的糖皮质激素诱导的肌肉萎缩大鼠产生积极影响，这两种实验条件分别为：慢性地塞米松（DEX）给药和慢性应激反应模型。（2）研究持续 28 天，在 45 只雄性 Wistar 大鼠上进行，这些大鼠随机分为六组。其中两组通过腹腔注射 2mg/kg/天的 DEX 并用植物油（DEX PL；n = 7）或维生素 D 600IU/kg/天（DEX SUP；n = 8）进行处理，另有一组用生理盐水（CON；n = 6）进行腹腔注射作为对照组。此外，还有两组大鼠通过冷水浸泡进行慢性应激（在一个玻璃盒中每天浸入 1 小时，玻璃盒中含有 1cm 深的冰/水混合物；温度约为 4°C），并用植物油作为安慰剂（STR PL；n = 9）或维生素 D 600IU/kg/天（STR SUP；n = 9）进行补充。最后一组为假应激大鼠（SHM；n = 6）。收集和称重血液、比目鱼肌、趾长伸肌、腓肠肌、胫骨前肌和股四头肌。处死大鼠后立即取出心脏、肝脏、脾脏和胸腺并称重。测量血浆皮质酮（CORT）和维生素 D 代谢物。（3）我们发现，两组冷水浸泡大鼠的 CORT 水平均升高；然而，它们并没有改变体重和肌肉重量。在外源性给予 DEX 的组中，体重和肌肉损失发生，除外源性给予维生素 D 的大鼠的比目鱼肌。DEX 处理的大鼠血清 25（OH）D 浓度降低，冷水浸泡不会影响维生素 D 水平。（4）我们的结果表明，维生素 D 补充剂可消除 DEX 诱导的肌肉损失，尤其是在比目鱼肌。
