International Journal of Medical Laboratory Research (Vol. 5 Issue 1, April 2020) www.ijmlr.com/IJMLR© All right are reserved 20 ISSN No. 2456-4400 Int J Med Lab Res 2020, 5(1):20-25 RESEARCH ARTICLE THE EFFECT OF INTERMITTENT NEGATIVE PRESSURE ON COLLAGEN CONCENTRATION IN MICE SKIN Osama S Abbadi 1 , Amal H Osman 2 , Nagla A M Ali 3 1 Department of Biochemistry, Faculty of Medicine, Omdurman Islamic University. 2 Department of Histology, National referral laboratories, Khartoum, Sudan. 3 Department of Histology and Cytology, East Nile College, Sudan. Received: 22 December, 2019/ Revision: 17 February, 2020/ Accepted: 10 March, 2020 ABSTRACT: Overview: Physical forces are known to affect biological structure and modulate the extracellular matrix. Collagen is the most abundant protein outside the cell, and it is clearly highlighted through Masson trichrome and van Geison’s stain. This research aimed to calculate the specific concentration of collagen within histology slides, after being subjected to sessions of intermittent negative pressure (INP), using Adobe® Photoshop® software and mice models. Objectives: To measure the collagen concentration in histology slides through Adobe® Photoshop®, using two types of stains: Masson trichrome, and van Gieson’s stain. Methods: Sixteen mice were put into sessions of INP ten minutes daily, for three weeks. Skin tissues were extracted from test and control sides. Stained slides were photographed and inserted in the Adobe® Photoshop® program to measure collagen concentration according to the specified calculated areas within the slides. Results: Masson’s trichrome slides gave a mean Collagen concentration of (58.4%) in the test slides, compared to the control which was (39.9%). In van Gieson stained slides, the collagen gave a mean concentration of (54.93%) in test slides and (41.32%) in the control. The difference was statistically insignificant in both staining. Conclusion: Applying INP to mice skin for three weeks did not significantly change the concentration of the collagen in the extracellular matrix. KEYWORDS: Collagen, Negative pressure, Masson’s trichrome, van Gieson stain. INTRODUCTION: Collagen is a protein with different subtypes and high abundance in Human and other animals 1,2 . Exactly 28 protein subtypes currently hold the name collagens 2,3,4 . Outside the cell, Collagens are mainly seen as long fibers of ordered or semi- ordered structures, and could vary in length 1 . It gives the extracellular matrix its strength and coherence 3 . Collagen fibers give the tissues its resilient ability, and mechanical forces can affect collagen alignment and expression. Uni- directional stretch in rat mesechymae promoted the synthesis of collagens I and III which RESEARCH ARTICLE Corresponding Author: Osama S Abbadi Department of Biochemistry, Faculty of Medicine, Omdurman Islamic University, Sudan.