Department of Integrative Biology, University of California at Berkeley, Berkeley, CA 94720-3140, USA.
Int J Mol Sci. 2023 Aug 25;24(17):13195. doi: 10.3390/ijms241713195.
Brain injuries (BI) are highly disruptive, often having long lasting effects. Inadequate standard of care (SOC) energy support in the hospital leads to dietary energy deficiencies in BI patients. However, it is unclear how underfeeding (UF) affects protein synthesis post-BI. Therefore, in a rat model, we addressed the issue of UF on the protein fractional synthesis rate (fSR) post-BI. Compared to ad libitum (AL)-fed animals, we found that UF decreased protein synthesis in hind-limb skeletal muscle and cortical mitochondrial and structural proteins ( ≤ 0.05). BI significantly increased protein synthesis in the left and right cortices ( ≤ 0.05), but suppressed protein synthesis in the cerebellum ( ≤ 0.05) as compared to non-injured sham animals. Compared to underfeeding alone, UF in conjunction with BI (UF+BI) caused increased protein synthesis rates in mitochondrial, cytosolic, and whole-tissue proteins of the cortical brain regions. The increased rates of protein synthesis found in the UF+BI group were mitigated by AL feeding, demonstrating that caloric adequacy alleviates the effects of BI on protein dynamics in cortical and cerebellar brain regions. This research provides evidence that underfeeding has a negative impact on brain healing post-BI and that protein reserves in uninjured tissues are mobilized to support cortical tissue repair following BI.
脑损伤（BI）具有高度破坏性，常伴有持久的影响。医院中 SOC 能量支持不足会导致 BI 患者的饮食能量不足。然而，UF 如何影响 BI 后的蛋白质合成尚不清楚。因此，我们在大鼠模型中研究了 BI 后 UF 对蛋白质合成率（fSR）的影响。与自由进食（AL）组相比，我们发现 UF 降低了后肢骨骼肌以及皮质线粒体和结构蛋白的蛋白质合成（≤0.05）。与未受伤的假手术组相比，BI 显著增加了左右皮质的蛋白质合成（≤0.05），但抑制了小脑的蛋白质合成（≤0.05）。与单独 UF 相比，UF 与 BI 联合（UF+BI）导致皮质脑区的线粒体、胞质和全组织蛋白的蛋白质合成率增加。AL 喂养减轻了 UF+BI 组中发现的蛋白质合成率增加，表明热量充足可减轻 BI 对皮质和小脑脑区蛋白质动态的影响。这项研究提供了证据，表明 UF 对 BI 后的脑愈合有负面影响，并且未受伤组织中的蛋白质储备被动员起来以支持 BI 后的皮质组织修复。
