الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Cutaneous ageing is a complex biological phenomenon consisting of two components; intrinsic ageing, which is largely genetically determined and extrinsic ageing caused by environmental exposure, primarily UV light.
In sun-exposed areas, these two processes are superimposed. The process of intrinsic skin ageing resembles that seen in most internal organs and is thought to involve decreased proliferative capacity leading to cellular senescence. Extrinsic ageing, more commonly termed photoaging, also involves changes in cellular biosynthetic activity but leads to gross disorganisation of the dermal matrix. Ageing of the skin is commonly associated with increased wrinkling, sagging and increased laxity.
Hyaluronic acid is a glycosaminoglycan polysaccharide synthesized by fibroblasts within the cell membrane and then released in the extracellular space. Hyaluronic acid used in mesotherapy is not cross-linked. It is not much stable. It is very fluid and it has a short half life.
Injection of hyaluronic acid is thought to promote skin rejuvenation by increasing both hydration and fibroblast activation. In fact, hyaluronic acid injected into the skin can stimulate fibroblast to express collagen type-1 (Col-1), and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1).
The aim of this work was to study the efficacy of intradermal injection of 2% non-cross linked hyaluronic acid in skin rejuvenation.
The study was carried on 30 female patients. All subjects were above 40 years with signs of photoaging. Patients with known hypersensitivity to HA ,pregnant or breast feeding females, patients with active skin lesions as infection or eczema and patients treated with other skin rejuvenation techniques in the previous 6 months were excluded from the study.
Twenty patients received intradermal injection of 2% non-cross linked HA in both sides of the face using the standard serial puncture technique with injections placed 1 cm apart and approximately 1 mm of the product was injected at each point. Ten patients received intradermal injection of saline as control using the same serial puncture technique. The aim of saline injection was to exclude the effect of percutaneous collagen induction by multiple needle application.
The patients received three injection sessions two weeks apart. They were photographed before and after the injections using skin analysis camera. The following parameters were recorded before and after; skin wrinkles score, skin texture score and UV spots score
The results were assessed and statistical analysis revealed statistically significant improvement in both wrinkles (p = 0.001) and UV spots (p =0.005). While the study failed to show statistically significant improvement in skin texture (p = 0.551).