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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, METHODS, METHODS, METHODS, METHODS, RESULTS. Meshes: Animals, Collagen, Gene Expression, Granuloma, Male, RNA, Messenger, Rats, Rats, Sprague-Dawley, Tumor Necrosis Factor-alpha, Wound Healing.
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Does tumour necrosis factor-alpha selectivity modulate expression of collagen genes in rat granulation tissue? Context: To study the effects of tumour necrosis factor-alpha (TNF-alpha) on granulation tissue in rats. Animal experiment. University Hospital, Finland. 48 rats in 6 groups. The test implants were treated with either a single or daily injections of 200 ng of TNF-alpha. The samples were collected 4 and/or 7 days postoperatively. Pro alpha 1 (I) and pro alpha 1 (III) collagen mRNA concentrations, hydroxyproline, nitrogen, uronic acids, and hexosamine content of the sponge; and ingrowth of new granulation tissue into the sponge. A single application of TNF-alpha resulted in no significant differences between the groups. After daily applications of TNF-alpha the accumulation of collagen hydroxyproline and volume of ingrowth of granulation tissue were significantly lower than in the controls. After 7 days there were significant reductions in the concentrations of RNA-ribose, nitrogen, and uronic acids. Daily injections of TNF-alpha reduced pro alpha 1 (I) collagen mRNA concentrations but those of pro alpha 1 (III) collagen mRNA levels were not lowered to the same extent.
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Repeated application of TNF-alpha was required to reduce the synthesis of collagen. This down-regulation was selective as pro alpha 1 (I) collagen mRNA concentrations were lowered more than those of pro alpha 1 (III) collagen mRNA. Final Decision: yes