Quelle est l’utilisation de l’acide hyaluronique pour la peau en Hindi?

Many skdansscientists have shown a growing interest dansAcide hyaluronique, as the La peauis an important reservoir of hyaluronic acideEt en plusan essential component of the extracellular mesenchyme (ECM), which plays an important role in the maintenance of the skin's morphology, structure Et en plusfunction. There are at least three English names for hyaluronic acide[1. 2]: Hyaluronan, Hyaluronan, Hyaluronan, Et en plusHyaluronan. 2]: hyaluronan, hyaluronicacid, hyaluronate. glucuronic acid, isolated from the vitreous body of the cow&#En 1934, il était le premier glycoside à contenir de l’acide hyaluronique [2].

Hyaluronic acid has good moisturising properties in Hindi, where it is used as a carrier for medicines, and skin care is closely linked to the pharmacological action of drugs [3]. Hyaluronic acid also plays an important role in the pathogenesis of many dermatological diseases4], as it is a natural macromolecule with the ability to retain water and moisturise the skin, and is widely used in cosmetics.

1 biologie de l’acide hyaluronique

1.1 structure biologique

Hyaluronic acid (HA) is an important class of aminoglycans, and its disaccharide does not contain sulfate groups, so it is also called non-sulfated aminoglycans. The disaccharide units of hyaluronic acid are glucuronic acid (GlcUA) and N-acetylglucosamine (GlcNAc), which are linked to GlcNAc by the β1,3 bond of GlcUA, and to the next GlcUA by the β1,4 bond of GlcNAc. UDP-glcA provides D-glycuronate for the Synthèse de l’acide hyaluronique through epimerisation at the C5 position, and hydrogen bonding between the 4-OH of GlcNAc and the O-acetyl group of GlcNAc is formed by bridging the water molecules, which is an important function in maintaining the natural activity of hyaluronic acid in the skin. At the same time, GlcUA has a strong acidic structure similar to that of AHA, but is completely neutral in the body. The bound form of hyaluronic acid exists as the hyaluronan récepteurcomplex (HARV) [5].

1.2 biosynthèse

The main site of hyaluronic acid biosynthesis in the body is the plasma membrane of fibroblasts or other cells, but also keratinocytes in the epidermis. Hyaluronic acid is synthesised rapidly in the body and is rapidly excreted or broken down. Its synthesis is influenced by hormones in the body, age, environmental factors and other factors. Hyaluronic acid is degraded by the enzyme hyaluronidase, which is produced by a variety of cells and first degrades hyaluronic acid to a medium-sized molecule of 20 KD containing 50-60 disaccharide units, which is then further degraded by other enzymes to oligosaccharide molecules. The half-life of hyaluronic acid in plasma is 2.5 min to 5.5 min, and urinary excretion is less than 1% of total clearance [6].

2 peau Et etacide hyaluronique

2.1 répartition dans la peau

Hyaluronic acid is synthesized by fibroblasts, keratinocytes or the plasma membrane of other cells. Hyaluronic acid exists in almost all tissues and fluids of the body, and the content of hyaluronic acid in the umbilical cord is 4100mg/L, and the content of hyaluronic acid in the bursal fluid is 1420mg/L~3600mg/L. However, the content of hyaluronic acid in the blood is only 0.01mg/L~0.1mg/L, and the content of hyaluronic acid in the urine is 0.1mg/L ~0.5mg/L. The amount in the urine is only 1% of the total amount excreted [6]. ~ However, blood contains at least 0.01mg/L to 0.1mg/L, and urine contains 0.1mg/L to 0.5mg/L. More than half of the body&#L’acide hyaluronique est localisé dans la peau. Il est enrichi dans l’épiderme Et etle derme, où il est le plus abondant au milieu de la strate spinosum Et etdiminue progressivement jusqu’à la couche basale; Cependant, l’acide hyaluronique n’existe pas du tout dans les strates granulosum et corneum. La coloration à l’acide hyaluronique révèle que l’intensité de la coloration est en ordre décroissant: espace intercellulaire épidermique, derme papillaire, derme réticulaire [1.2].

2.2 acide hyaluronique et cicatrisation des plaies

Hyaluronic acid also plays an important role in the process of skin wound healing7], Hyaluronic Acid is one of the substances that reach the wound very early after injury, and the one that reaches the wound is the high molecular hyaluronic acid. When the body is in a metabolically stable state, HA binds to fibrinogen in the blood and forms a fibrous reticulum as a skeleton in combination with fibrin. hyaluronic acid is degraded under the action of hyaluronidase in 6-10 days, which stimulates the subsequent wound repair until the wound is completely repaired.

The time of inactivation of the enzyme of Hyaluronic Acid is in line with the change from the cell wandering and proliferation of the wound to the differentiation of the cells and maturation of the wound. Hyaluronic acid also enhances the action of thrombin at the site of injury, acting as a catalyst for fibrous clot formation. It also promotes pathological phagocytosis by monocytes. Due to its water-retaining and hydrating properties, HA facilitates cell movement by enlarging the intercellular space, creating a suitable environment for inflammatory cells to enter and maintain their activity. At the same time, hyaluronic acid promotes the entry and adhesion of epidermal cells, but also the proliferation and travelling of fibroblasts.

Il a été démontré que lorsqu’il est appliqué sur des ulcères de peau,L’acide hyaluronique favorise la guérison des plaies, encore plus que les traitements conventionnels [8]. Son effet hydratant favorise également un environnement hydrologique constant dans la peau, propice à la cicatrisation des plaies. Il est également à noter que l’utilisation de préparations d’acide hyaluronique sur la surface de la peau des femmes pendant la grossesse peut réduire l’apparence des vergetures et faciliter leur récupération après l’accouchement [1,13].

2.3 acide hyaluronique et vieillissement de la peau

Hyaluronic acid, as a major component of the extracellular interstitium, has a strong water-absorbent capacity that facilitates the flow of nutrients and plays an important role in maintaining the elasticity of the skin [1,13]. As the body continues to age, the skin's hyaluronic acid content becomes less and less, reducing the amount of water, leading to shrinkage of its contents and a decrease in viscosity. At the same time, the exchange of substances and energy between the skin&#Le liquide tissulaire et la circulation sanguine sont réduits, la peau est privée de nutriments adéquats et les cellules vieillissent progressivement et perdent leur fonction.

Several in vivo Études de cashave confirmed that Hyaluronic Acid levels decrease during the maturation process. In vitro experiments have shown that hyaluronic acid levels also decrease during cellular ageing [1,2,9]. Specifically, hyaluronic acid staining decreases in the middle stratum spinosum and basal layer of the epidermis during aging, and in the dermis around collagen fibres and between collagen and elastin fibres, while staining increases in the papillary layer of the dermis. The decrease in hyaluronic acid content of the dermis can cause the aging skin to lose its fullness and microvascular support, leading to the appearance of wrinkles and a decrease in skin elasticity. Pulsed EMF treatment, however, resulted in a sense of fullness, a reduction in wrinkles, and an increase in the content of amino-polysaccharides such as hyaluronic acid in the extracellular mesenchyme and between elastin fibres and collagen fibres. Other researchers have found that hyaluronic acid is reduced in the upper epidermis, and that hyaluronic acid is still present in the dermis of aged skin, but not in the epidermis. A decrease in free hyaluronan and an increase in bound hyaluronan were also found, suggesting that hyaluronan-binding proteins (HABPs) are also strongly associated with ageing, and that their levels are elevated during ageing, with fetal bound hyaluronan accounting for 7% of total hyaluronan compared with 23% in aged skin.

Fetal fibroblasts exhibit greater cell mobility than adults, which is related to the amount of Hyaluronic Acid produced by these cells [10]. Adult cells produce less Hyaluronic Acid, as hyaluronidase inhibits the movement of fetal fibroblasts, and a significant correlation was found between hyaluronic acid production and cell movement. A significant correlation was also found between hyaluronic acid production and cell wandering, while there is still no clear correlation between the decline in hyaluronic acid content and age.

3 Application d’acide hyaluronique dans les cosmétiques

3.1 rétention d’eau et propriétés hydratantes de l’acide hyaluronique

Masse moléculaire Relative de4 × 10⁶ of hyaluronic acid molecular chain length of 10μm, due to the straight chain axis of hydrogen bonding between monosaccharides, Hyaluronic Acid molecules in the space of a rigid helical column, radius of 200nm, the inner group of a large number of hydroxyl groups by the hydrophilicity of the hydrophilic group, the solution and the affinity for the water is about 1,000 times the mass of its own, but also because of the helix of the space of the outside has a hydrophobicity, so that the water in the spiral column immobilised, the water in the water. The hydrophobicity on the outside of the helical space makes the water immobile and not easy to be lost inside the helical column. At the same time, hyaluronic acid solution has unique hydrodynamic properties, with good viscoelasticity and strain, the low concentration of the solution is mainly viscous, while the high concentration of elasticity [1~3].

Despite the inconsistent results, it is clear that Hyaluronic Acid can act as a cellular barrier and lubricant to collagen, while at the same time facilitating the separation of tightly bound cells and allowing the cells to travel to the site of proliferation (e.g., site of injury, etc.). The synthesised Hyaluronic Acid forms directly into the extracellular matrix and is generally found as a periplasm on the surface of cell membranes. Hyaluronic acid is mainly found in rapidly proliferating, rebuilding and repairing tissues. Its biological role is mainly to maintain the extracellular space of tissue cells, to accelerate the flow of ions, solutes and nutrients and to maintain tissue hydration. This is due to the excellent water-absorbing and moisturising properties of Hyaluronic Acid.

Specifically, Hyaluronic Acid-rich ECM can draw a large amount of water from the dermis, and at the same time prevent evaporation and loss of water due to the epidermal lipid barrier, thus maintaining a constant hydrological environment in the skin []. Therefore, hyaluronic acid is widely used in cosmetics as the most ideal natural moisturising factor. Therefore, many cosmetic manufacturers at home and abroad make use of hyaluronic acid' L leffets naturels d’absorption d’eau et d’hydratation pour ajouter de l’acide hyaluronique aux cosmétiques, les rendant adaptés à différents types de peau, climats et environnements. Il permet non seulement aux fabricants de gagner certains avantages, mais joue également une certaine fonction pour répondre aux besoins des consommateurs, et il est particulièrement adapté aux personnes ayant la peau sèche et dans des environnements froids et secs.

3.2 effets anti-âge de l’acide hyaluronique

Hyaluronic acid has excellent functions in improving the physiological conditions of the skin, such as providing sufficient moisture to the stratum corneum, strengthening the skin barrier, providing an excellent external environment for the synthesis of dermal collagen fibres and elastin fibres, and enhancing the supply of a variety of nutrients, which is effective in skin care and skin maintenance. In addition, in vitro or animal studies have found that: ① hyaluronic acid bound on the cell surface can block the release of some cellular enzymes to the outside of the cell to reduce the production of free radicals, and hyaluronic acid bound on the cell surface can restrict several enzymes that produce free radicals and lipid peroxidation from approaching the cell membrane, and reduce the influx of hydroxyl radicals on the surface of the cell membrane.

Free radicals play an important role in destroying cell structure, generating lipid peroxidation and causing aging. ② Low molecular weight hyaluronic acid (LMW-HA) was also found to have anti-inflammatory and pathological inhibiting effects in rodents. Hyaluronic acid can provide a suitable matrix for cell proliferation and differentiation, and at the same time, the hyaluronic acid bound on the cell surface can directly transmit the external growth signals to the cells, which can directly promote the proliferation, reconstruction and repair of the tissues, and promote the recovery of the ECM function, so as to recover the elasticity and fullness of the skin. Its excellent matrix space structure and ability to maintain water balance play an important role in improving the internal environment of skin tissues and the supply of nutrients, thus showing a certain anti-aging effect. Therefore, people use hyaluronic acid to inhibit the pathological phagocytosis of animal cells, use it to inhibit inflammation, inhibit the production of free radicals, etc., and water retention and moisturisation combined with the application of cosmetic products, to achieve anti-wrinkle and anti-inflammatory, rejuvenation and anti-ageing effect [11,12].

Although the polymer Hyaluronic Acid was found to have the effect of delaying skin aging in animal studies, these so-called anti-aging cosmetics have been found to have the effect of delaying skin aging in animal studies. However, most of these so-called anti-aging cosmetic substances are based on their temporary hydration or moisturising effect, which reduces blemishes, imperfections and other undesirable symptoms from the skin' S de la peau, ce qui est particulièrement important pour favoriser la synthèse de l’acide hyaluronique. Ce n’est qu’en pénétrant dans le derme et en stimulant la synthèse de l’acide hyaluronique que le processus de vieillissement de la peau peut être arrêté. Chez la souris, l’administration d’oestradiol dans la peau favorise la synthèse de l’acide hyaluronique1,2,12]. Des études In vitro ont montré que l’ajout de CaCl₂ au milieu de culture inhibe la synthèse d’ha par les kératinocytes, tandis que l’acide microformique favorise la production d’acide hyaluronique. L’ajout d’ascorbate et de cortisone aux fibroblastes cutanés en culture a réduit la synthèse d’acide hyaluronique. Les expériences de descendance des fibroblastes ont également confirmé que la production d’acide hyaluronique par les fibroblastes après 24 générations était deux fois plus faible que celle des fibroblastes après seulement neuf générations, ce qui indique que la synthèse de l’acide hyaluronique par les fibroblastes senescents est réduite, et que l’ajout d’hyaluronidase au milieu de culture a stimulé la re-synthèse de l’acide hyaluronique et stimulé la prolifération cellulaire [13].

At the same time, there are few published studies on the evaluation of the effects of HA application on normal human skin. Overseas experimental studies are generally based on damaged skin, as it is generally considered to be unable to cross the normal skin barrier.4 Stem synthesised [12] that small molecular amounts of HA (LMW-HA) (150 KD) derived from bovine trachea hydrolysed by endopeptidases were used Dans l’hommeexperiments, and concluded that HA was beneficial for normal hydration. The authors also claimed that the slow response of intact skin to cosmetic and dermatological treatments is not conducive to a correct interpretation of their efficacy and that the limitations of their study are obvious. The results of in vitro or population studies on the effects of HA when added to cosmetic products are generally based on measurements of skin capacitance, water evaporation and keratinisation after application3 [14], and there is a lack of studies on the delay of skin hydration. 14], there is a lack of objective, comprehensive and scientific evaluation of skin ageing. Although domestic and foreign cosmetic manufacturers are using HA, the exact effect of HA on normal skin (moisturising and anti-aging) has not yet been scientifically proven in a complete and systematic way.

En conclusion, l’acide hyaluronique a un effet certain et clair lorsqu’il est administré In vivo ou par d’autres moyens, avec une excellente absorption d’eau et des fonctions hydratantes, favorisant l’apport de nutriments à la peau et maintenant la constance de la peau' S et prévenir et soulager le vieillissement de la peau. Par conséquent, il a été largement utilisé dans les produits cosmétiques. Dans le passé, l’ha était dérivé d’extraits de tissus animaux (tels que la couronne de poulet, le cordon ombilical, la vache et le#39;s eye or microbial fermentation, etc.), and due to the possibility of contamination and allergy, it has now been transferred to the production of genetically engineered strains.The research and development of the production of HA as well as the exact efficacy of HA on the normal skin of the human body deserves further study, so as to facilitate its wide application in cosmetics.

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