A hypothesis on biological protection from space radiation through the use of new therapeutic gases as medical counter measures

Table 2 Cited Properties of NO as a Medical Gas with Suggested Chemical/Biological Mechanisms.

Biochemical Mechanism	Notes
radical scavenging antioxidant	• NO reacts with peroxy and oxy radicals generated during the process of lipid peroxidation. The reactions between NO and these ROS can terminate lipid peroxidation and protect tissues from ROS-induced injuries [70].
	• induces the rate-limiting antioxidant enzyme, heme oxygenase (HO)-1 thus imparting resistance to H₂O₂ induced cell death [71].
	• in bacteria, activates the redox-sentive transcriptional regulator protein (oxyR), resulting in the subsequent expression of protein protective against ROS [72].
anti-inflammatory	• inhibiting P-selectin expression and leukocyte recruitment [73].
decreased radiosensitivity	• vasodilator through relaxation of vascular tone by stimulating soluble guanylate cyclase (sGC) and increased cGMP content in vascular smooth muscle cells [23].

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