ИССЛЕДОВАНИЕ МИКРОЦИРКУЛЯЦИИ КРОВИ В КОЖЕ РАЗЛИЧНЫХ ОБЛАСТЕЙ ТЕЛА МЕТОДОМ ЛДФ

Козлов В.И.¹, Гурова О.А.²

¹Доктор медицинских наук, профессор,

²Кандидат биологических наук, доцент,

Российский университет дружбы народов, Москва

ИССЛЕДОВАНИЕ МИКРОЦИРКУЛЯЦИИ КРОВИ В КОЖЕ РАЗЛИЧНЫХ ОБЛАСТЕЙ ТЕЛА МЕТОДОМ ЛДФ

Аннотация

С помощью лазерной допплеровской флоуметрии (ЛДФ) изучали параметры микроциркуляции крови в коже различных топографо-анатомических областей тела у здоровых лиц в возрасте 18-24 лет. Особенности строения кожи и ее микроциркуляторного русла в этих участках тела исследованы гистологическими методами и с помощью капилляроскопии. Определены нормативные показатели состояния микроциркуляции крови в коже головы, туловища и основных сегментов верхней и нижней конечностей. Величина параметров ЛДФ в коже разных областей тела зависит от плотности функционирующих капилляров, толщины эпидермиса и глубины залегания микрососудов. Ключевые слова: ЛДФ, микроциркуляция крови, области тела.

Kozlov V.I.¹, Gurova O.A.²

¹MD, Full Professor,

²PhD in biological sciences, associate Professor,

Peoples’ Friendship University of Russia, Moscow

THE STUDY OF BLOOD MICROCIRCULATION IN THE SKIN OF DIFFERENT AREAS OF THE BODY BY LDF

Abstract

Using laser Doppler flowmetry (LDF) studied parameters of the skin microcirculation of different topographo-anatomic regions of the body at healthy persons age of 18-24 years. Features of the structure of the skin and microvessels in these areas of the body are investigated by histological methods and capillaroscopy. Normative parameters of a condition of microcirculation in a skin of head, body and main segments of hand and leg are determined. The magnitude of the parameters of  LDF affect the density of functioning capillaries, the thickness of epidermis and the depth of the microvasculature in the skin. Keywords: LDF, skin microcirculation, regions of the body. Assessment of the state of microcirculation in different body areas is of great importance in clinical practice and research. Method of laser Doppler flowmetry (LDF) is a modern, effective and non-invasive method of microcirculation diagnostics [3-5].  However, until recently, regulatory figures of LDF-grams of the skin of different topographic areas of the body have not been clearly defined. Moreover their dependence on the specific structure of the microcirculation in the skin of these areas have not been studied [1, 2]. The purpose of this study was to determine the values of LDF of the skin of different body areas in healthy young people, and demonstrate the peculiarities of microcirculation of skin in these areas. Material and methods of research Morpho-functional peculiarities of blood microcirculation were studied in the skin of 15 anatomical areas of the body in 80 healthy males aged 18-24 years. Morphological and functional characteristics were recorded in the skin of the breast (5th intercostal space, right anterior axillary line), abdomen (lateral edge of rectus abdominis muscle), forehead, ear lobule, arm (the medial surface of the lower third), forearm (ventral surface of the lower third), hand (1st dorsal interosseous space), ring finger (palmar and the dorsal surface of the distal phalanx), hip (the medial surface of the lower third), leg (posterior surface of the lower third), medial and lateral malleoli, foot (1st dorsal interosseous space), great toe (posterior surface of the distal phalanx). The microcirculation status was evaluated using laser analyzer of blood flow "LAKK-01" ("Lazma", Russia) in subjects sitting in accordance with the methodological recommendations [4]. Biomicroscopic study of skin capillaries was performed by microscope MLK-3MT (LOMO) with the use of the capillaroscopy method . Histological methods (standard staining of the skin with hematoxylin and subsequent eosin) revealed the depth of blood vessels in the same skin area of cadaver. All data was processed by the methods of variation statistics. Results of the study Blood microcirculation figures in the skin of different body areas, obtained by LDF method, are presented in table 1.  

Table 1 - Parameters of blood microcirculation in the skin of the different areas of the body

The area of the body	PM	SD	IF
Forehead	18,7±0,5	1,8±0,1	1,18±0,02
Ear lobule	27,9±1,2	3,3±0,3	1,56±0,04
Breast	14,6±1,0	2,0±0,2	1,53±0,05
Abdomen	12,4±0,6	1,2±0,1	1,51±0,04
Arm	10,1±1,0	1,2±0,1	1,65±0,05
Forearm	6,7±0,3	0,8±0,1	1,63±0,05
Hand	7,1±0,3	1,2±0,1	1,94±0,07
Finger (palmar surface)	25,4±0,9	3,1±0,2	2,09±0,05
Finger (dorsal surface)	17,1±1,0	2,9±0,2	1,89±0,06
Hip	6,5±0,3	0,7±0,03	1,67±0,06
Leg	6,1±0,3	0,5±0,04	1,54±0,06
Medial malleolus	6,1±0,2	0,6±0,03	1,57±0,06
Lateral malleolus	6,7±0,2	0,6±0,04	1,57±0,05
Foot	7,2±0,4	0,6±0,1	1,53±0,05
Great toe (dorsal surface)	6,9±0,4	0,8±0,1	1,59±0,06

  The value of basal blood flow is characterized by the parameter of microcirculation (PM) and its variability - the standard deviation (SD), - depending on the studied area. The highest rates can be seen in the skin of the ear lobule and palmar surface of the ring finger, the lowest - in the skin of the leg and medial malleolus (R ≤ 0,01). High values of standard deviation indicate the activity of the proper vascular mechanisms of blood flow modulation in the skin of the terminal body areas. In the skin of the trunk and lower extremities the obtained figures were lower. That may be a consequence of oppression of the active vasomotor mechanisms or the prevalence of tonic sympathetic influence in the regulation of blood flow. Integral characteristic of microcirculation – the index fluctuations of blood flow (IF) - gives an idea of the ratio of active and passive mechanisms of modulation of blood flow. IPM in the skin of the trunk and the proximal parts of the extremities in healthy young people, where active and passive influence on the blood flow is balanced, has average values. Low values of the IPM were noticed in the skin of the forehead, high - in the skin of the ring finger (R ≤ 0,05). Amplitude-frequency spectrum (ASF) of LDF-grams was analyzed in order to study the contribution of individual mechanisms of regulation to the state of the skin microcirculation in different body areas. The results of the analysis of ASF of the LDF-grams are presented in table 2. The dominant rhythm of fluctuations of blood flow is a vasomotor rhythm caused by the activity of the smooth muscle tissue components in the wall of microvessels of the preсapilliary part of microcirculation, as evidenced by the maximum contribution to the total spectrum power VLF and LF-oscillations. These fluctuations characterize the mechanism of active modulation of blood flow. High frequency (HF) and pulse (CF) oscillations are caused by the pressure drops of blood microcirculation and reflect the state of passive mechanisms of modulation of blood flow. Their contribution to the total spectrum power of LDF-grams is significantly low and in healthy subjects does not exceed 15%.  

Table 2 - Spectral characteristics of oscillations of skin blood flow in the skin of different anatomical areas of the body (contribution of frequency components to the total spectrum power in %)

The area of the body	Frequency components
	VLF	LF	HF	CF
Forehead	50,1±2,21	37,9±2,4	9,2±0,67	2,8±0,3
Ear lobule	53,0±2,33	35,4±2,56	9,2±0,99	2,4±0,42
Breast	44,5±1,16	42,5±0,98	10,9±0,69	2,13±0,28
Abdomen	52,2±0,48	39,8±0,36	6,4±0,29	1,6±0,11
Arm	49,9±1,19	40,4±0,98	8,6±0,63	1,1±0,25
Forearm	50,6±1,08	39,3±1,06	9,1±0,65	1,0±0,09
Hand	53,2±2,01	39,6±1,77	6,2±0,35	1,0±0,14
Finger (palmar surface)	54,1±0,78	38,4±0,35	6,6±0,42	0,9±0,07
Finger (dorsal surface)	56,4±0,89	36,8±0,61	6,1±0,29	0,7±0,06
Hip	50,9±0,73	40,1±0,52	7,6±0,58	1,4±0,15
Leg	51,4±0,92	37,9±0,84	9,2±0,77	1,5±0,15
Medial malleolus	49,8±1,01	40,9±0,88	8,1±1,07	1,2±0,12
Lateral malleolus	51,8±2,06	36,5±2,15	9,8±0,85	1,9±0,21
Foot	50,3±0,96	38,8±0,48	9,1±0,86	1,8±0,45
Great toe (dorsal surface)	54,8±1,57	35,2±1,27	8,7±0,79	1,3±0,18

  During the biomicroscopic study it was found that high values of GR are measured in those areas of the skin where the density of capillaries is high and the number of arterio-venous anastomoses is the greatest (Table 3). The lowest number of functional capillaries was revealed in the skin of the shoulder, hips and abdomen. The highest - in the skin of a nail folds of fingers and the ear lobe, which also has a significant number of arterio-venous anastomoses.  

Table 3 - Features of the structure of the skin in different anatomical areas of the body

The area of the body	Density functional capillaries1 mm2	Thickness epidermis, mcm	Depth
			capillaries papillary layer, mcm	vessels of subpapillar plexus, mcm
Forehead	28±0,4	52±0,4	55±0,35	87±0,35
Ear lobule	54±0,6	-	-	-
Breast	16±0,5	53±0,45	56±0,35	89±0,45
Abdomen	14±1	38±0,6	49±0,4	106±0,95
Arm	12±0,4	74±0,71	78±1,21	123±0,75
Forearm	16±0,4	72±1,31	83±1,11	121±0,85
Hand (dorsal surface)	48±0,5	88±0,85	89±0,85	133±0,65
Hand (palmar surface)	-	516±2,32	530±1,26	619±0,55
Ring finger (dorsal surface)	57±0,7	131±2,52	94±0,65	167±1,11
Hip	14±0,8	62±0,95	66±0,7	85±0,45
Leg	16±0,6	129±1,11	136±0,8	147±0,55
Medial maleolus	22±0,5	146±0,9	149±0,7	174±0,6
Foot (dorsal surface)	36±0,6	138±0,95	145±0,85	167±0,8
Foot (plantar surface)	-	631±2,47	652±1,71	727±1,26
Great toe (dorsal surface)	37±0,5	144±0,7	150±1,31	188±0,96

  The figures of LDF-grams are also influenced by the thickness of epidermis and depth of microvessels. The thickness of the epidermis, examined by histological methods, varied from 38±0.6 microns in the abdomen to 516±2.3 and 631±2.5 in the skin of the palms and soles, respectively. The figures of LDF-grams in the skin of the lower limbs are lower than in the skin of the upper limbs, in compliance with a greater thickness of the epidermis and greater depth of microvessels.  

Fig. 1 - The ratio of the density of capillaries and microcirculation in the skin of the breast and different parts of the upper limb

  The reduction of PM was observed in the skin of the proximal parts of the extremities (shoulder and thigh) in comparison with the figures obtained in the skin of the trunk together with the trend of gradual increase of the index closer to the distal parts of the limbs (Fig. 1). In the skin of the upper extremity this pattern is expressed more vividly: the value of PM in the skin of the finger significantly (p ≤ 0,01) surpasses those in the skin of other parts of the extremity. Thus, the value of the baseline LDF increases correspondingly with the relocation of the examined area from the body to the distal parts of the upper extremity.  That correlates with the increase of capillaries density in the skin of these areas. Low values of LDF-grams in the skin of the different parts of the lower extremities are caused by the depth of location of the microvessels and the influence of the position of the lower limbs.

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