Nitric oxide and wound healing

مرکز و کتابخانه مطالعات اسلامی به زبان های اروپایی

منو

" Nitric oxide and wound healing "
M. Shabani

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1113396
Doc. No	:	TLpq304287162
Main Entry	:	M. Shabani
Title & Author	:	Nitric oxide and wound healing\ M. Shabani
College	:	The University of Akron
Date	:	1996
student score	:	1996
Degree	:	Ph.D.
Page No	:	165
Abstract	:	Nitric oxide (NO) is a free radical with a multitude of tissue specific functions. Its expanding range of functions includes host defense, signal transduction, vasodilation, and neurotransmission. Many wound resident cells including macrophages synthesize NO, which is subsequently metabolized to NO3\sp-. The present study was designed to further clarify the level of NO production during wound healing. Rats fed low NO3\sp- diets were wounded, following the establishment of baseline urinary NO3\sp- levels. The rate of wound closure was measured using computer based video imaging analysis (VIA), while urinary NO3\sp- levels were monitored for several weeks post-wounding. After wounding, both arginine-free diet and arginine fed animals responded with a many-fold increase in the urinary NO 3\sp- levels, demonstrating that dietary arginine is not necessary for the sudden increase in NO3\sp- output immediately after wounding. It was found that rats fed arginine-free diet responded to LPS challenge with a typical increase in NO3\sp- output. Lack of dietary arginine apparently does not prevent the NO producing activity of macrophages during the early phase of healing, but NO synthesis suppressed in the later stages of tissue repair. Post-wound urinary NO3\sp- levels in both steroid-treated and diabetic rats were significantly lower compared to controls. Steroid-treated and diabetic rats also demonstrated suppressed NO3\sp- response to LPS challenge. VIA analysis confirmed impaired wound healing in the early post-wound period with both models. In addition, topical application of nitric oxide synthase (NOS) inhibitors, L-NMMA and L-NO2A, caused reduced NO synthesis during wound healing, indicating that post-wound increase in urinary NO3\sp- levels were due to enhanced NO synthesis primarily at the wound site. Topical delivery of NO releasing polymer (PEIC-NO) resulted in a significant enhancement of the healing process (p < 0.05) in normal wounded rats. No hypotensive effects of PEIC-NO application were observed, probably due to the controlled release of NO from PEIC-NO. NO was also shown to be delivered transdermally through the use of NONOates. Results obtained from experiments in this dissertation reveal that delayed wound healing is associated with attenuated NO production, and that site specific delivery of NO via NONOates may overcome healing impairment.
Subject	:	arginine
	:	Biochemistry
	:	Biological sciences
	:	Health and environmental sciences
	:	Pharmacology
	:	Pure sciences