FR2917299A1 - Wrinkles cosmetic treatment method for skin, involves exposing skin area to source emitting light whose wavelength spectrum is in between specific nanometer and light intensity of specific millicandela during predetermined period - Google Patents

Abstract

The method involves exposing an area of skin to be processed to a light source (20) constituted of a rechargeable battery emitting the light whose wavelength spectrum is in between 590 to 598 nanometer and light intensity between 8000 and 12000 millicandela during a predetermined period of 30 seconds to 2 minutes, where the light source has a set of LEDs (210). Light is emitted under the form of impulse burst of light, where frequency of the impulse is 5 hertz and duration of the impulse is one milli second. An independent claim is also included for a device for processing wrinkles cosmetic treatment in skin.

Description

The present invention relates to a method for the cosmetic treatment of

  skin by light and a device for the implementation of such a cosmetic treatment of the skin. Maintaining a youthful appearance is a constant concern today. There are thus a large number of cosmetic treatments intended to prevent the appearance of wrinkles and to visibly reduce the wrinkles already present. Among these cosmetic treatments include, for example, the regular application of so-called anti-wrinkle lotions or creams, peels intended to remove one or more superficial layers of the skin, the injection of collagen or surgical methods such as than the facelift. Recently, methods of treating the skin with light have appeared. Such methods use, for example, a laser or a source of intense pulsed light. Intense Pulse Light (IPL) is also a technology widely used in aesthetic care. It complements the action of lasers in the treatment of signs of aging such as photo-depigmentation and wrinkles. Flash lamps are high-intensity discharge lamps filled with a rare gas, xenon, for example. They work by converting stored electrical energy into intense bursts of radiant energy. The light emitted covers the ultraviolet, visible and infrared light spectrum regions, i.e. from about 350 nm to about 1200 nm. Unlike lasers, flash lamps are therefore polychromatic. This broad spectrum of the lamp allows to act simultaneously on different types of skin problem. Indeed, it has been determined that a given range of wavelengths can have a particular beneficial effect on the skin. For example, red light, which corresponds to a wavelength spectrum of about 625 to 750 nm, promotes depigmentation of the skin. Blue light (450-500 nm) is known to kill the bacteria responsible for acne. It is then necessary to use filters allowing selection of the desired wavelength depending on the treatment envisaged. This particularity of flash lamps explains that their manipulation must be reserved for experienced practitioners. Another disadvantage of flash lamps, as well as lasers, is the relatively large size of these devices.

  As an alternative to the use of lasers or flashlamps, a technology has developed around the use of light-emitting diodes (LEDs) for the cosmetic and therapeutic treatment of the skin. Light emitting diodes have the advantage of being inexpensive in comparison with lasers or flashlamps and, because of their lower light intensity, do not present any danger of burns or other injuries to the skin if exposure does not occur. is not properly performed. Light-emitting diodes emit light in a spectrum that extends from visible to infrared. Some are said to be monochromatic but emit light whose wavelength is within a small spectrum corresponding to a given color of light. Others, such as white diodes, are polychromatic. It is therefore possible to use light-emitting diodes for the cosmetic treatment of the skin and to select them according to the result that it is desired to obtain. One of the targets in the cosmetic treatment of wrinkles, as well as in the prevention of the appearance of wrinkles, is collagen. Collagen is a fibrous protein secreted by the fibroblasts of the connective tissue This protein ensures the cohesion of the connective tissue The appearance of the wrinkles is due, to a large extent, to the deterioration of the connective tissue and to the decrease with the age of the collagen synthesis by fibroblasts. It is now known that the exposure of the skin to light can stimulate collagen synthesis or even prevent the deterioration of collagen present in the connective tissue. This is the case, for example, of light whose length of wave is between 570 and 590 nm, which corresponds substantially to the yellow light of the visible spectrum of light. One possible explanation is that at this wavelength range, the light flow can inactivate collagenase, an enzyme that degrades collagen. But if the choice of a range of wavelengths is important for a treatment given by the light, it is also important to select the adequate light intensity and the duration of exposure of the area to be treated which will, in combination , to obtain a satisfactory result. The applicants have thus identified a range of wavelengths and a range of light intensities which, in combination, make it possible to reduce and prevent the appearance of skin wrinkles by stimulating the synthesis of collagen by fibroblasts. . The present invention thus relates to a method of cosmetic treatment of wrinkles of an area of the skin by light. The method according to the invention is characterized in that it comprises a step of exposing said zone of the skin to be treated to a light source emitting light in a wavelength spectrum of between 590 and 598 nm, for a luminous intensity of between 8000 and 12000 millicandelas (mcd) and for a determined period, advantageously between 1 and 2 min.

  The applicants have observed, surprisingly, that the cosmetic treatment according to the invention makes it possible to stimulate the synthesis of collagen by the fibroblasts of the skin in a significant manner. This is the result of combining the range of wavelengths and the intensity of the emitted light used. As mentioned above, stimulating collagen synthesis helps reduce skin wrinkles and prevent them from appearing. According to one characteristic of the invention, said light source is composed of a plurality of light-emitting diodes. According to one characteristic of the invention, said light is emitted in the form of bursts of light pulses.

  Advantageously, said exposure step is repeated every two days for two weeks. Advantageously, said light source is disposed at a distance from said area to be treated between 5 and 10 cm. The present invention further relates to a device for carrying out the method of cosmetic treatment by the light of wrinkles of an area of the skin as just described. Such a device according to the invention comprises a housing comprising a light source. It is characterized in that said light source emits light in a wavelength range between 590 and 598 nm, with a light intensity of between 8000 and 12000 mcd. According to one characteristic of the invention, said light source comprises a plurality of diodes, advantageously arranged in a matrix.

  According to yet another characteristic of the invention, said device comprises a timer provided for controlling the duration of light emission of said light source. Advantageously, said power source consists of a rechargeable battery. Advantageously, said device comprises a protective wall of said light source, preferably in the form of a flap provided to be able to slide along said housing from a position in which it covers said light source to a position in which said light source is not covered. The characteristics of the invention mentioned above, as well as others, will emerge more clearly on reading the following description of an exemplary embodiment, said description being given in relation to the attached drawings, among which: FIG. . 1 is a front view of a device for the cosmetic treatment of wrinkles according to the invention. Fig. 2 is a side view of a device for the cosmetic treatment of wrinkles according to the invention. The device for the cosmetic treatment of the skin by the light according to the invention shown in FIG. 1 comprises a housing 10 having a light source 20. The light source 20 is composed of a plurality of light-emitting diodes, such as the diode 210. These are assembled into a matrix 21, preferably of rectangular or square shape. The matrix 21 may comprise a number of light-emitting diodes advantageously between fifteen and seventy-five, ordered in several rows and columns. A protective wall 22 may, in the exemplary embodiment shown in FIG. 2, cover the matrix 21 in order to prevent any degradation of the diodes 210. The protective wall 22 may be transparent to the wavelengths emitted by said diodes 210 and permanently fixed on the housing 10, as the example shown in FIG. FIG. 2. However, in an advantageous variant of the invention not shown, the protective wall 22 may be in the form of a flap provided to be able to slide along said housing 10 from a position in which it covers said light source 20 to a position in which said light source 20 is not covered. Each diode 210 of the light source 20 emits a light in the visible spectrum, of yellow-orange color, whose wavelengths are between 590 5 and 598 nm and whose intensity is between 8000 and 12000 mcd. Advantageously, the light source 20 emits by light pulses. To do this, the device of the invention comprises an electrical pulse generator means 50 supplying the diodes 210, with a pulse frequency of approximately 5 Hz and a duration of 1 ms. As can be seen in FIG. 2, the device of the invention further comprises a timer 60 connected, via the pulse generator 50, to the matrix of diodes 21. It controls the pulse generator 50 for a predetermined period of time so that bursts of light pulses with a frequency of about 5 Hz during said duration, for example between 30 seconds and 2 minutes. Said device also comprises a power supply battery 40 for the general power supply of the device 1, that is to say the timer 60, the pulse generator 50 and the matrix of diodes 20. A start button M and a stop button A present on the housing 10 are also connected to the battery 40 to enable the user to respectively turn on or off the operation of said device of the present invention. The housing 10 has dimensions enabling it to be portable and can advantageously be held in one hand. The device 1 according to the invention can be used in a cosmetic treatment of the wrinkles of an area of the skin by stimulating the synthesis of collagen by the fibroblasts. Such a method comprises a step during which the user grasps the device 1 in his hand and places it at a distance from the area of the skin to be treated of between 5 and 10 cm. It presses the start button M and allows the device 1 to operate through the timer 60 for an exposure period of between 30 seconds and 2 minutes.

  During this step, the light source 20 emits a yellow light whose wavelength spectrum is between 595 and 598 nm and the light intensity is between 8000 and 10000 mcd. The light source 20 emits, in addition, said light in the form of light bursts characterized by the electrical pulses generated by the pulse generator 50. As mentioned above, the frequency of the light pulses is about 5 Hz and the duration of each light pulse is about 1 ms. Very good results were obtained with a repeated exposure period once every two days for two weeks. The selection of both a range of wavelengths and an appropriate light intensity makes it possible to obtain a surprising result, as attested by the analyzes described in the following. In addition, the light emission in the form of bursts of light pulses contributes to the success of the process for the cosmetic treatment of wrinkles. Test 1: Evaluation of the Cosmetic Treatment Process According to the Invention on an Area of the Skin

  Three types of normal human skin fragment obtained from three different donors, respectively, were each grown in an insert disposed in a well of a culture dish comprising a culture medium allowing survival of the skin fragments. A porous membrane made it possible to ensure exchanges between the interior of the inserts and the interior of the wells. The culture media were renewed three times a week for the duration of the experiment, from the first day of OJ to the twelfth day D12. Each type of skin fragment was divided into four lots: - lot 1: control skin. batch 2: skin aged experimentally with OJ after exposure to UV A and UV B radiation. It is known that UV A and UV B radiation make it possible to reduce the metabolism of fibroblasts and thus to reduce collagen synthesis. They also allow to alter the molecules present in the connective tissue. -lot 3: skin aged experimentally at 0 in the same way as the skin fragments of the second batch, then subjected to a treatment according to the invention, that is to say, exposed to a light source capable of emitting a light whose wavelength spectrum is between 590 and 598 nm, for a luminous intensity of between 8000 and 12000 mcd, said light source being composed of 75 diodes. batch 4: skin aged experimentally at 0 in the same way as the skin fragments of the second and third batch, then subjected to a treatment according to the invention, that is to say, exposed to a light source of light whose wavelength spectrum is between 590 and 598 nm, for a light intensity of between 8000 and 12000 mcd, said light source being composed of 20 diodes. Lots 3 and 4 were exposed to the light source for a period of 1 min each day for 12 days.

  The following analyzes were performed on each batch.

  Histological quantification of collagen

  The collagen present in the superficial dermis and the middle dermis of the skin fragments of each lot was evidenced by Sirius red staining and quantified morphometrically by computer-assisted image analysis. The results are expressed as percentage of area occupied by collagen, in the middle dermis and the superficial dermis and are reported in Table I.

  Table I DERMAL SURFACE DERMA MEDIUM Lot 1 67.6 +/- 8.5 68.6 +/- 9.2 Lot 2 49.5 +/- 3.6 59.45 +/- 2.95 Lot 3 61, 1 +/- 8 69.9 +/- 7.2 Lot 4 59.65 +/- 6.3 69 +/- 4.36 The amount of collagen decreased, compared with lot 1, after UV treatment A, and B, in the superficial dermis (49.5% vs. 67.6%) and in the middle dermis (59.45% vs. 68.6%) of batch 2. After batch 3 has been exposed to UV A and B then subjected to a treatment according to the invention, the amount of collagen increased significantly in the superficial dermis and in the middle dermis, in comparison with the lot 2 (61.1% against 49.5% and 69.5%). , 9% vs. 59.45%, respectively). Likewise, after batch 4 has been exposed to UV A and B and then subjected to a light source according to the invention, the amount of collagen has increased significantly in the superficial dermis and in the middle dermis, in comparison with the lot 2 (59.65% vs. 49.5% and 69% vs. 59.45%, respectively). The results obtained with lots 3 and 4 are not significantly different.

  Biochemical assay of total collagen

  On D12, the skin fragments of each batch were digested with pepsin overnight at 4 ° C. in a 0.5M acetic acid solution. This method is used to isolate newly synthesized collagen. After grinding with a potter, the amount of collagen (g / ml) was determined by a spectrocolorimetric assay at 540 nm after specific fixing of Sirius red on collagen (Sircol Collagen Asay, Interchim). For each lot, the amount of collagen has been related to the amount of total protein and is expressed in g of collagen per mg of total protein. The total protein amount was assayed by spectrophotometric assay at 562 nm. The average for each lot type was calculated and reported in Table II.

  Table II Amount of collagen in relation to the total amount of protein (g / mg) Lot 1 808.8 +/- 206.65 Lot 2 657.9 +/- 179.7 Lot 3 713.5 +/- 163 Lot 4 1181.45 +/- 118 After exposure of lot 2 to UV A and B, the collagen synthesis is greatly reduced in comparison with lot 1 (657.9 xg / mg against 808.8 g / mg, respectively). ). Comparing the results obtained for lot 4 (1181.45) with those obtained for lot 2 (657.9 g / mg), but also with those obtained for lot 1 (808, 8 gg / mg) it is found that the synthesis of collagen has been stimulated very significantly, and thus restored, after the skin fragments have been subjected to a cosmetic treatment according to the invention. Collagen synthesis was stimulated more moderately in batch 3 (713.51_1g / mg) than in batch 4, which means that the number of diodes is an important factor.

  A new test was then made from skin fragments of 8 other donors using a device according to the invention comprising 20 diodes.

  Test 2: Evaluation of the cosmetic treatment method of a skin zone according to the invention by a device comprising 20 diodes 15 Human skin fragments obtained from eight donors were each grown in an insert placed in a well. a culture dish comprising a culture medium allowing the survival of the skin fragments. A porous membrane made it possible to ensure exchanges between the inside of the inserts and the interior of the wells. Culture media were renewed three times a week for the duration of the experiment, from the first day OJ to the twelfth day D12. Each type of skin fragment was divided into four lots: - lot 1: control skin. lot 2: skin experimentally aged at OJ after exposure to UV A (8 J / cm 2) and UV B (2 J / cm 2) radiation. batch 3: skin aged experimentally at 0 in the same way as the skin fragments of the second batch, then subjected to a treatment according to the invention, that is to say, exposed to a light source capable of emitting light in a wavelength spectrum between 590 and 598 nm, for a luminous intensity of between 8000 and 12000 mcd, said light source being composed of 20 diodes. Lot 3 was exposed to the light source for a period of 1 min, daily for 12 days. The following analyzes were performed on each batch.

  Histological quantification of collagen

  The collagen present in the superficial dermis and the middle dermis of the skin fragments of each lot was evidenced by Sirius red staining and quantified morphometrically by computer-assisted image analysis. The results are expressed as percentage of area occupied by collagen, in the middle dermis and the superficial dermis. and are reported in Table III.

  Table III SURFACE DERMA DERME MEDIUM Lot 1 75.8 +/- 10.18 76.35 +/- 12.1 Lot 2 59.63 +/- 11.22 69.43 +/- 10.78 Lot 3 69.85 + / - 13.8 72.6 +/- 8.4 The amount of collagen decreased significantly for lot 2 after UV treatment A and B, compared with lot 1, in the superficial dermis (59.63 % vs 75.8%) (Student paired test, p = 0.00025). In the middle dermis the amount of collagen decreased but not significantly (69.43% against 76.35%). After batch 3 was exposed to UV A and B and then subjected to a treatment according to the invention, the amount of collagen increased significantly in the superficial dermis, compared with batch 2 (69.85% vs. 59%). , 63%). There is, however, no significant increase in the middle dermis. An increase in the amount of collagen in the superficial dermis alone can be interpreted to mean that collagen has been repaired in the superficial dermis, with collagen synthesis occurring in the middle dermis.

  Biochemical assay of total collagen At day 12, the skin fragments from each lot were digested with pepsin overnight at 4 ° C. in 0.5M acetic acid solution. This method is used to isolate newly synthesized collagen. After grinding with a potter, the amount of collagen (g / ml) was assayed by a spectrocolorimetric assay method at 540 nm after specific attachment of Sirius red to collagen (Sircol Collagen Asay, Interchim). For each lot, the amount of collagen has been related to the amount of total protein and is expressed in g of collagen per mg of total protein. The total protein amount was assayed by spectrophotometric assay at 562 nm. The average for each lot type was calculated and reported in Table IV.

  Table IV Amount of collagen in relation to the total amount of protein (g / mg) Lot 1 667.5 +/- 256.5 Lot 2 421.5 +/- 219.4 Lot 3 559.3 +/- 205, After exposure of lot 2 to UV A and B, collagen synthesis was greatly decreased in comparison with lot 1 (421.5 g / mg vs 667.5 g / mg, respectively) (Student's test, p = 0.003). ). If we compare the results obtained for batch 3 (559.3) with those obtained for batch 2 (421.5 g / mg), we see that the collagen synthesis was stimulated in a very important and significant way, and thus restored, after the skin fragments have been subjected to a cosmetic treatment according to the invention.

  The device according to the invention for the implementation of the cosmetic treatment method according to the invention thus makes it possible to stimulate and restore collagen synthesis of a skin zone in a major way and thus to fight against the appearance of wrinkles or reduce them.

Claims (14)

  1) A method for the cosmetic treatment of wrinkles of a skin zone by light, characterized in that it comprises a step of exposing said zone of the skin to be treated to a light source (20) emitting a light of which the spectrum in wavelengths is between 590 and 598 nm, for a luminous intensity of between 8000 and 12000 mcd and for a determined period.   2) Cosmetic treatment method according to claim 1, characterized in that said light source (20) is composed of a plurality of diodes (210).   3) Cosmetic treatment method according to one of the preceding claims, characterized in that said light is emitted in the form of bursts of light pulses.   4) Cosmetic treatment method according to claim 3, characterized in that the frequency of said pulses is about 5 Hz and the duration of said pulses is about 1 ms. 20   5) Cosmetic treatment method according to one of the preceding claims, characterized in that said determined period is between 30 seconds and 2 minutes.   6) Cosmetic treatment method according to one of the preceding claims, characterized in that said exposure step is repeated every two days for two weeks.   7) Cosmetic treatment method according to one of the preceding claims, characterized in that said light source (20) is disposed at a distance from said area to be treated between 5 and 10 cm.   8) Device (1) for a cosmetic light treatment of wrinkles of a skin area according to the method according to one of claims 1 to 7, said device comprising a housing comprising a light source (20), characterized in that said light source (20) emits a light whose wavelength spectrum is between 590 and 598 nm, with a luminous intensity of between 8000 and 10000 mcd.   9) Device (1) according to claim 7, characterized in that said light source (20) comprises a plurality of diodes (210).   10) Device (1) according to one of claims 8 or 9, characterized in that said diodes (210) are assembled to form a matrix (21).   11) Device (1) according to one of claims 8 to 11, characterized in that it comprises a timer (60) provided for controlling the duration of light emission by said light source (20). 15   12) Device (1) according to one of claims 8 to 12, characterized in that it comprises a power source (40) consisting of a rechargeable battery.   13) Device (1) according to one of claims 8 to 13, characterized in that it comprises a protective wall (22) of said light source (20).   14) Device (1) according to claim 14, characterized in that said protective wall (22) is slidable along said housing (10) from a position in which it covers said light source (20) to a position in which said light source (20) is not covered.