犬的皮肤生物物理参数随年龄、性别和品种的变化 ...

王帆

Variations in skin biophysical parameters with age, sex and breed in dogs

犬的皮肤生物物理参数随年龄、性别和品种的变化

 

作者：Je-Seong Kwon1 | Eun- Yeong Bok2 Yong-ho Choe3 | Jaemin Kim4 Ji-Seon Yoon

 

翻译：王帆

 

Abstract

摘要

Background: Understanding the physiological and biophysical character istics of skin provides information for developing appropriate management strategies for skin diseases. However, in dogs, variations in skin biophysical parameters, such as age, sex and breed, remain poorly understood.

Hypothesis/Objectives: This study analysed three biophysical characteris tics of healthy dog skin (hydration, pH and sebum content) and investigated the effects of sex, age and breed.

Materials and Methods: One hundred forty- nine dogs without skin prob lems were enrolled. Skin hydration, pH and sebum content were measured using a multifunctional skin physiology monitor. The dogs were divided into four age groups: ＜1year，1-6year，7-12years and ＞13 years.

Results: Skin hydration levels were significantly lower in the >13 years group than in the 1–6 years and 7–12 groups. Additionally, skin pH levels in the >13 years group were significantly lower than in the 7–12 group. Furthermore, skin biophysical parameters among the five breed groups – beagles (n = 37), Malteses (n = 18), miniature poodles (n = 24), cocker spaniels (n = 11) and Pomeranians (n = 12) – revealed that skin hydration and pH were significantly higher in beagles than those of Malteses and miniature poodles.

Conclusions and Clinical Relevance: These findings indicate that biophysi cal properties, including skin hydration and pH, vary with age and breed. This study provides fundamental data on the effects of age, sex and breed on the biophysical characteristics of dog skin.

背景：了解皮肤的生理及生物物理特性，可提供适当的皮肤疾病治疗策略。然而，对于犬的皮肤生物物理参数的变化，如年龄，性别和品种，仍然知之甚少。

假设/目的：本研究分析了健康犬皮肤的三个生物物理特性（水合、pH和皮脂含量），并研究了性别、年龄和品种对其的影响。

材料与方法：选取149只无皮肤问题的犬。采用多功能皮肤生理监测仪测定皮肤含水量、pH值和皮脂含量。犬被分为4个年龄组：<1岁，1-6岁，7-12岁和＞13岁。

结果：>13岁组皮肤含水量显著低于1 ~ 6岁组和7 ~ 12岁组。此外，>13岁组的皮肤pH水平显著低于7 ~ 12岁组。此外，五个品种组的皮肤生物物理参数-比格犬（n = 37）、马尔济斯犬（n = 18）、迷你贵宾犬（n = 24）、可卡犬（n = 11）和博美犬(n = 12) -显示比格犬的皮肤含水量和pH值显著高于马尔济斯犬和迷你贵宾犬。

结论和临床意义：这些发现表明，生物物理特性，包括皮肤水分和pH值，随年龄和品种而变化。本研究为研究年龄、性别和品种对犬皮肤生物物理特性的影响提供了基础数据。

 

KEYWORDS age, breed, dog, pH, sebum, skin hydration

关键词：年龄，品种，犬，pH值，皮脂，皮肤水分

 

INTRODUCTION

介绍

The skin is a vital organ that serves as a barrier, preventing micro-organisms and irritants from causing external chemical or physical damage. Biophysical parameters are commonly used to assess the structural and functional integrity of the skin barrier. The biophysical characteristics of the skin include skin hydration, sebum content, transepidermal water loss and pH. Skin hydration, defined as the amount of water in the stratum corneum that maintains a water gradient between the skin surface and deeper epidermal layers, is maintained by natural moisturising factors (e.g. urea, lactic acid and pyrrolidone carboxylic acid) and intercellular lipids (e.g. sphingolipids and ceramides). Skin pH plays a critical role in protecting the skin from invasion by micro-organisms and in regulating the surface structure and stability of matrix lipids. Sebum, a liquid composed of nonpolar lipids (e.g. triglycerides, free fatty acids, wax esters, squalene, cholesterol esters and cholesterol) secreted by the sebaceous glands, prevents excessive moisture loss, helps maintain optimal hydration levels and acts as a chemical barrier against potential pathogens.

皮肤是一个重要的器官，起到屏障的作用，防止微生物和刺激物引起外部的化学或物理损伤。生物物理参数是评估皮肤屏障结构和功能完整性的常用方法。皮肤的生物物理特性包括皮肤水分、皮脂含量、经表皮失水和pH值。皮肤水分是指角质层中维持皮肤表面和深层表皮之间水梯度的水分量，由天然保湿因子（如尿素、乳酸和吡咯烷酮羧酸）和细胞间脂质（如鞘脂和神经酰胺）维持。皮肤pH值在保护皮肤免受微生物侵袭、调节皮肤表面结构和基质脂质稳定性方面发挥着关键作用。皮脂是一种由皮脂腺分泌的由非极性脂类（如甘油三酯、游离脂肪酸、蜡酯、角鲨烯、胆固醇酯和胆固醇）组成的液体，可防止水分过多流失，帮助保持最佳水合水平，并作为抵御潜在病原体的化学屏障。

 

In humans, skin biophysical measurements vary with age, sex, ethnicity, body site and environmental factors. Skin hydration tends to decrease with age, and Caucasians exhibit higher dryness with age than Chinese individuals. Additionally, skin pH tends to be higher in the elderly than in young children. Sebum se cretion also decreases slightly with age and is reported to be higher in males in association with higher testos terone levels.

在人类，皮肤生物物理测量值因年龄、性别民族、身体部位和环境因素而异。皮肤含水量随年龄增长而下降，白种人的皮肤干燥程度高于中国人。此外，老年人的皮肤pH值往往高于儿童。皮脂分泌也随着年龄的增长而轻微减少，据报道，雄性皮脂分泌增多与较高的睾酮水平有关。

 

In dogs, previous studies have indicated that skin hy dration varies with anatomical sites and breed. Dog skin pH, which is more alkaline than human skin, can vary by age, sex and anatomical sites. Physiological or pathological changes caused by external substances or environmental factors can be quantified by measuring the biophysical parameters of the skin, thereby contributing to dermatological advancements in cosmetics and pharmaceuticals. Therefore, understanding the physiological and biophysical characteristics of skin provides information for developing appropriate man agement strategies for skin diseases. This study inves tigated the effects of breed, sex and age on biophysical parameters using noninvasive methods.

以前的研究表明，犬的皮肤含水量因解剖部位和品种而异。犬皮肤的pH值比人类皮肤的碱性更强，可能因年龄、性别和解剖部位而异。外部物质或环境因素引起的生理或病理变化可以通过测量皮肤的生物物理参数来量化，从而促进皮肤科产品和药物的进步。因此，了解皮肤的生理和生物物理特性可为制定适当的皮肤病管理策略提供信息。本研究采用非侵入性方法研究了品种、性别和年龄对生物物理参数的影响。

 

METHODS AND MATERIALS

材料和方法

Animals

动物

In order to assess skin biophysical parameters in healthy dogs based on age, sex and breed, 149 dogs without skin problems were enrolled. Dogs were en rolled that were not diagnosed with skin diseases at the time of measurement and did not have skin lesions such as erythema or scale. Additionally, to minimise underlying diseases, skin measurements were per formed primarily on dogs that came to the hospital for regular medical check- ups. Age groups were de fined as: 13 years (14.33 ± 1.20, n = 30). Additionally, there were four sex groups consisting of female (n = 6, average age 7.10 ± 3.10 years), spayed female (n = 68, 7.6 ± 5.30), male (n = 8, 4.44 ± 3.70) and castrated male (n = 67, 6.28 ± 4.76). Breed comparisons were conducted across five groups: beagles (n = 37, average age 5.13 ± 3.39 years), cocker spaniels (n = 11, 12.56 ± 4.08), Malteses (n = 19, 4.80 ± 5.51), Pomeranians (n = 12, 6.50 ± 3.28) and miniature poodles (n = 27, 6.23 ± 5.73). All experimental procedures used in this study were ap proved by the Jeonbuk National University Institutional Animal Care and Use Committee (NON2024- 153- 001).

为评估健康犬不同年龄、性别和品种的皮肤生物物理参数，共纳入149只无皮肤病的犬。在测量时未诊断出皮肤疾病且没有发红或皮屑等皮肤病变的犬被纳入研究。此外，为了尽量减少潜在的疾病，皮肤测量主要是对来医院定期体检的犬。年龄13岁（14.33±1.20,n = 30）。雌性6例，平均年龄（7.10±3.10）岁；已绝育雌性68例，平均年龄（7.6±5.30）岁；雄性8例，平均年龄（4.44±3.70）岁和已去势雄性67例，平均年龄（6.28±4.76）岁；犬种比较分5组：比格犬37只，平均年龄（5.13±3.39）岁；可卡犬11只，平均年龄（12.56±4.08）岁；马尔济斯犬19只，平均年龄（4.80±5.51）岁；博美犬12例，平均年龄（6.50 ± 3.28）。本研究中使用的所有实验程序均经全北国立大学机构动物护理和使用委员会（NON2024- 153- 001）证实。

 

Measurement of skin biophysical parameters

皮肤生物物理参数的测量

In order to minimise the influence of hair on the meas urements, the inguinal region, which had relatively thin hair, was selected. Assessments were performed on areas with the least hair. Skin hydration, pH and sebum levels were analysed using a multifunctional skin physi ology monitor (Skin- O- Mat [corneometer for skin hy dration, pH meter for skin pH, sebumeter for sebum]; Cosmomed GmbH). Skin hydration and pH were meas ured repeatedly in the same area of inguinal region. Sebum was measured in a different area of inguinal region because sebum level could have changed once absorbed by the sebumeter. Mean values were calculated for analysis. Additionally, to minimise the seasonal influence, the experiment was conducted mainly in au tumn and spring (September to November and March to May).

为了尽量减少毛发对测量的影响，我们选择了毛发相对稀疏的腹股沟区域。在毛发最少的区域进行评估。使用多功能皮肤生理监测仪（Skin- O- Mat，皮肤水分测量仪，皮肤pH值测量仪，皮脂测量仪）分析皮肤水分、pH值和皮脂水平；Cosmomed GmbH)。在腹股沟相同区域重复测量皮肤含水量和pH值。由于皮脂水平一旦被皮脂计吸收，皮脂水平可能会发生变化，因此在腹股沟区域的不同区域测量皮脂。计算平均值用于分析。此外，为了减少季节的影响，试验主要在秋季和春季（9 - 11月和3 - 5月）进行。

 

Statistical analysis

统计学分析

Statistical analyses were performed using SpSS StatiSticS v29 (IBM Corp.). Normality was assessed using the Shapiro–Wilk test. As the data were not normally dis tributed, they were analysed using the Kruskal–Wallis test with post hoc Dunnett's test. Statistical signifi cance was set at p < 0.05. Spearman's rank correlation test was used to analyse the correlation between skin biophysical parameters. Correlation coefficients (r) of <−0.2 and >0.2 indicate weak negative and positive correlations, respectively, and r-values <−0.4 and >0.4 indicate significant negative and positive correlations, respectively. Data were presented as medians and in terquartile range (IQR).

使用SpSS StatiSticS v29 （IBM Corp.）进行统计分析。采用Shapiro-Wilk检验评估正态性。由于数据不是正态分布，因此使用Kruskal-Wallis检验和事后Dunnett检验进行分析。以p < 0.05为差异有统计学意义。采用Spearman秩相关检验分析皮肤生物物理参数之间的相关性。<−0.2和>0.2的相关系数(r)分别表示弱的负相关和正相关，r值<−0.4和>0.4分别表示显著的负相关和正相关。数据以中位数和四分位距（四分位距，IQR）表示。

 

RESULTS

结果

Skin biophysical parameters in different age groups

不同年龄组皮肤生物物理参数

Median (IQR) skin hydration levels [arbitrary units, a.u.] were 18.96 (17.57) for dogs 13 years old (Figure 1a). Statistical analysis revealed that the skin hydration levels in dogs >13 years old were significantly lower than in dogs 1–6 years old (p = 0.031) and 7–12 years old (p = 0.024). Median (IQR) pH values were 6.18 (1.33) for dogs 13 years old (Figure 1b). Skin pH values in dogs >13 years old were significantly lower (more acidic) than in dogs 1–6 years old (p = 0.039). Median (IQR) sebum levels [μg/cm2] were 1 (2.5) for dogs 13 years old (Figure 1c). No significant differences in sebum levels were found between the age groups.

13岁犬的皮肤含水量中位数（IQR）（任意单位，a.u.）为18.96(17.57)（图1a）。统计分析显示，＞13岁的犬的皮肤含水量显著低于1-6岁（p = 0.031）和7-12岁（p = 0.024）的犬。13岁犬的pH值中位数（IQR）为6.18(1.33)（图1b）。“与1-6岁的犬相比，>13岁的犬的皮肤pH值显著降低（酸性更强）（p = 0.039）。”13岁犬的皮脂水平中位数（IQR）[μg/cm2]为1(2.5)（图1c）。皮脂水平在各年龄组间无显著差异。

 

Skin biophysical parameters in different sex groups

不同性别的皮肤生物物理参数

Median (IQR) skin hydration levels [a.u.] were 20.92 (0.97) for intact females, 19.14 (15.53) for spayed females, 20.83 (9.43) for intact males and 22.96 (17.38) for castrated males (Figure 2a). Median (IQR) pH levels were 6.10 (0.83) for intact females, 6.18 (1.07) for spayed females, 6.53 (1.44) for intact males and 6.44 (1.37) for castrated males (Figure 2b). Median (IQR) sebum levels [μg/cm2] were 0.5 (1.88) for intact females, 1 (2.54) for spayed females, 0.25 (1.38) for intact males and 0.5 (1.25) for castrated males (Figure 2c). No significant differences in skin hydration, pH or sebum levels were observed between the sex groups.

皮肤含水量的中位数（IQR）]在未绝育雌性中为20.92(0.97)，在已绝育雌性中为19.14(15.53)，在未去势雄性中为20.83(9.43)，在已去势雄性中为22.96(17.38)（图2a）。未绝育雌性的pH水平中位数（IQR）为6.10(0.83)，已绝育雌性为6.18(1.07)，未去势雄性为6.53(1.44)，已去势雄性为6.44(1.37)（图2b）。皮脂水平的中位数（IQR）[μg/cm2]：未绝育雌性为0.5(1.88)，已绝育雌性为1(2.54)，未去势雄性为0.25(1.38)，已去势雄性为0.5(1.25)（图2c）。皮肤含水量、pH值或皮脂水平在性别组间无显著差异。

 

Skin biophysical parameters in different five breeds

不同品种的皮肤生物物理参数

Median (IQR) skin hydration levels [a.u.] by breed were 29.22 (16.86) for beagles, 20.28 (8.44) for cocker spaniels, 18.06 (10.42) for Malteses, 19.448 (22.22) for Pomeranians and 14.91 (5.74) for miniature poodles (Figure 3a). Beagles had significantly higher skin hydration levels than Malteses (p = 0.023) and miniature poodles (p < 0.001). Median (IQR) pHs by breed were 6.82(1.3) for beagles, 6.52 (0.67) for cocker spaniels, 5.94 (0.91) for Malteses, 6.375 (1.1) for Pomeranians and 5.75 (0.72) for miniature poodles (Figure 3b). In terms of pH, Beagles also showed significantly higher values than Malteses (p = 0.003) and miniature poodles (p < 0.001). Median (IQR) sebum levels [μg/cm2] by breed were 1.5 (5) for beagles, 0.5 (0.75) for cocker spaniels, 0 (1.75) for Malteses, 0.5 (1.13) for Pomeranians and 1 (4.62) for miniature poodles (Figure 3c). No significant differ ences in sebum levels were found between the breed groups.

皮肤含水量的中位数（IQR）比格犬为29.22(16.86)，可卡犬为20.28(8.44)，马尔济斯犬为18.06(10.42)，博美犬为19.448(22.22)，迷你贵宾犬为14.91(5.74)（图3a）。比格犬的皮肤水合水平显著高于马尔济斯犬（p = 0.023）和小型粪便（p < 0.001）。不同品种的pH中位数（IQR）为：比格犬6.82(1.3)，可卡犬6.52(0.67)，马尔济斯5.94(0.91)，博美犬6.375（1.1）和迷你贵宾犬5.75(0.72)（图3b）。在pH值方面，比格犬的pH值也显著高于马尔济斯犬（p = 0.003）和迷你贵宾犬（p < 0.001）。不同品种的皮脂水平中位数（IQR）[μg/cm2]为比格犬1.5(5)、可卡犬0.5（0.75）、马尔济斯犬0（1.75）、博美犬0.5（1.13）和迷你贵宾犬1(4.62)（图3c）。不同品种间的皮脂水平无显著差异。

 

Correlations between biophysical parameters

生物物理参数之间的相关性

Spearman's rho data were used to identify correlations among skin hydration, sebum and pH. A positive cor relation was observed between skin hydration and pH (p < 0.001; r = 0.403) (Figure 4). No statistically signifi cant correlations were observed between skin hydra tion and sebum levels or between skin pH and sebum levels (data not shown). Figure 4 shows the scatter plots of these correlations.

Spearman's rho数据用于确定皮肤水分，皮脂和pH之间的相关性。皮肤水分和pH之间存在正相关(p < 0.001；r = 0.403)（图4）。未观察到皮肤水合和皮脂水平之间或皮肤pH值和皮脂水平之间有统计学意义的相关性（数据未显示）。图4显示了这些相关性的散点图。

 

DISCUSSION

讨论

This study investigated skin hydration, pH and sebum levels in the inguinal region of dogs of different breeds, ages, and sexes, revealing variations in these param eters with age and breed.

本研究调查了不同品种、年龄和性别的犬的腹股沟区皮肤水分、pH和皮脂水平，发现这些参数随年龄和品种的变化而变化。

 

In human, hydration levels decrease in infant skin and significantly decrease in the elderly, primarily as a result of a reduction in natural moisturising factors. Likewise, in this study, although no statistically sig nificant difference was observed in dogs 13 years old showed significantly lower skin hydration than those 1–6 years and 7–12 years old. This result aligns with a previous study reporting a decline in ceramide levels, a key factor in skin moisture retention, with aging in dogs.

在人类中，婴儿皮肤的水合水平降低，老年人皮肤的水合水平显著降低，主要是由于天然保湿因子的减少。同样，在本研究中，虽然13岁的犬与1-6岁和7-12岁的犬相比没有统计学上的显著差异，但其皮肤含水量显著低于1-6岁和7-12岁的犬。这一结果与之前的一项研究报告一致，神经酰胺是皮肤保湿的关键因素，随着犬的年龄增长，神经酰胺水平下降。

 

Regarding pH, dogs >13 years old had significantly lower (more acidic) pH levels than those 1–6 years old.Although pH values in dogs 7–12 years old were higher than in dogs >13 years old, the general trend suggests that pH decreases with age, which is contrary to previous findings in humans. The strong correlation be tween skin hydration and pH observed in this study may explain these findings. pH can vary depending on several factors, including skin hydration, atmospheric conditions, sweat secretion and the level of physical activity. Unlike humans, whose skin contains eccrine glands distributed across the body, dogs predominantly have apocrine glands. Because apocrine sweat has a higher pH than eccrine sweat, it has been suggested that secretions from the apocrine glands could contribute to elevated pH levels in dogs. In fact, one study found that excited dogs had higher cutaneous pH levels than nonexcited dogs and that hyperhidrosis patients exhibited a more alkaline pH than normal dogs. Therefore, secretions from apocrine glands may contribute to higher skin hydration, with their components further elevating pH, leading to a strong positive correlation between hydration and pH levels.

在pH方面，>13岁的犬的pH水平显著低于1-6岁的犬。虽然7-12岁的犬的pH值高于>13岁的犬，但总体趋势表明，pH值随着年龄的增长而降低，这与之前在人类中的发现相反。本研究中观察到的皮肤水分和pH之间的强相关性可能可以解释这些发现。pH值取决于几个因素，包括皮肤水分、大气条件、汗液分泌和身体活动水平。与人类不同，人类的皮肤上有分布在全身的小汗腺，犬主要有顶浆汗腺。由于顶浆汗腺的pH值高于小汗腺，因此有人提出，大汗腺的分泌物可能导致犬的pH值升高。事实上，一项研究发现，兴奋的犬比非兴奋的犬有更高的皮肤pH值，多汗症患犬现出比正常犬更多的碱性pH值。因此，顶浆汗腺的分泌物可能有助于提高皮肤的水分，其成分进一步提高pH，导致水分和pH水平之间的强正相关。

 

No variance in biophysical parameters was observed between sex groups, differing from previous studies in both humans and dogs, which found higher sebum con tent in males. In this study, most dogs were neutered; thus, the biophysical parameters of the skin were less affected by hormones. Additionally, as the number of enrolled female dogs was too small, it might be difficult to establish any significant correlation. A future study including large numbers of intact female and male dogs will provide further understanding of the skin biophysi cal parameters between the different sex groups.

本研究未观察到性别组之间的生物物理参数有差异，这与之前在人类和犬中进行的研究不同，之前的研究发现雄性的皮脂含量较高。在这项研究中，大多数犬已节育；因此，皮肤的生物物理参数受激素的影响较小。此外，由于纳入的母犬数量太少，可能很难建立任何显著的相关性。未来的研究包括大量未节育雌犬和雄犬，将进一步了解不同性别组之间的皮肤生物物理参数。

 

Among the biophysical skin parameters, sebum lev els are generally low, with large variations between in dividuals. Sebum levels measured in the inguinal area of the enrolled dogs were lower than those reported for the human leg, a low- sebum area. In humans, large variations in sebum levels occur at different anatomical sites, with lower levels in the leg and dorsal areas compared to other body sites. Future studies should evaluate sebum levels at various anatomical sites.

在皮肤的生物物理参数中，皮脂水平普遍较低，个体差异较大。在入组犬的腹股沟区域测量的皮脂水平低于报告的人腿，这是一个低皮脂区域。在人类，皮脂水平的巨大差异发生在不同的解剖部位，与其他身体部位相比，腿部和背部的皮脂水平较低。未来的研究应评估不同解剖部位的皮脂水平。

 

This study evaluated skin hydration, pH and sebum content across five breeds, and observed significant breed- related differences. Beagles exhibited relatively higher values for all three parameters. Few studies have compared the skin parameters between different breeds. In previous studies comparing beagles with large breeds, such as hounds, Labrador retrievers and fox terriers, beagles were reported to have lower skin hydration levels. However, the present study observed higher skin hydration levels in beagles. Because the subjects were mainly small breeds, the observed differences might have been influenced by breed- specific factors. Thus, further research involving a broader range of breeds is required to conduct a com prehensive comparative analysis of skin parameters.

本研究评估了5个品种的皮肤含水量、pH值和皮脂含量，并观察到显著的品种相关差异。比格犬的3个参数值均相对较高。很少有研究比较不同品种之间的皮肤参数。在之前的研究中，将比格犬与大型犬（如猎犬、拉布拉多猎犬和猎狐犬）进行比较，比格犬的皮肤水分水平较低。然而，本研究观察到比格犬的皮肤含水量更高。由于研究对象主要是小型品种，观察到的差异可能受到品种特异性因素的影响。因此，需要更广泛品种的进一步研究，对皮肤参数进行全面的比较分析。

 

This study has several limitations. Environmental factors such as living conditions (temperature and hu midity) and bathing frequency were not fully controlled, potentially influencing the biophysical parameters. Furthermore, measurements were limited to the ingui nal area, precluding determination of differences based on body area. Additionally, the relatively small sample size may limit the generalisability of the findings. Further research with large numbers of dogs is needed to investigate additional biophysical factors such as TEWL or other influencing factors, such as anatomical sites and seasonal differences.

本研究有几个局限性。环境因素如生活条件（温度和湿度）和洗澡频率没有完全控制，可能影响生物物理参数。此外，测量仅限于腹股沟区域，因此无法确定基于身体区域的差异。此外，相对较小的样本量可能限制了研究结果的普遍适用性。我们需要对大量犬进行进一步研究，以调查其他生物物理因素（如经表皮水分流失）或其他影响因素（如解剖部位和季节差异）。

 

In conclusion, the present study revealed that skin biophysical parameters of skin hydration and pH vary with age and breed. This study provides fundamental data on the effects of age, sex and breed on the biophysical characteristics of dog skin. These skin biophysical parameters should be considered when understanding skin diseases and developing skincare products, especially for older individuals.

综上所述，本研究揭示了皮肤水分和pH的生物物理参数随年龄和品种而变化。本研究为研究年龄、性别和品种对犬皮肤生物物理特性的影响提供了基础数据。在了解皮肤疾病和开发皮肤产品时，应考虑这些皮肤生物物理参数，尤其是对老年个体。

 

 

 

FIGURE 1 Skin hydration, pH and sebum levels in different age groups. (a) Skin hydration levels in dogs aged 13 years were significantly lower than those in dogs aged 1–6 and 7–12 years. (b) Dogs aged 13 years had significantly lower (more acidic) pH levels than those aged 1–6 years. (c) Sebum levels were not statistically significant. Kruskal–Wallis test with post hoc Dunnett's test (*p < 0.05)

图1不同年龄组的皮肤含水量、pH值和皮脂水平(a) 13岁犬的皮肤水合水平显著低于1 ~ 6岁和7 ~ 12岁犬。(b) 13岁的犬的pH水平显著低于1-6岁的犬。(c)皮脂水平无统计学意义。Kruskal-Wallis检验与事后Dunnett检验（*p < 0.05）

 

 

FIGURE 2 Skin hydration, pH and sebum levels in different sex groups. Statistical analysis revealed no significant differences in skin hydration (a), pH (b) and sebum levels (c) between the sexes. Kruskal–Wallis test with post hoc Dunnett's test

图2不同性别的皮肤含水量、pH值和皮脂水平统计分析显示，皮肤水分(a)、pH (b)和皮脂水平(c)在性别之间没有显著差异。Kruskal-Wallis检验与事后Dunnett检验

 

 

FIGURE 3 Skin hydration, pH and sebum levels in different breed groups. (a) Beagles had significantly higher skin hydration levels than Malteses (p = 0.049) and miniature poodles (p < 0.001). (b) Beagles also showed significantly higher pH than Malteses (p = 0.008) and miniature poodles (p < 0.001). (c) No significant differences were observed in sebum levels between different breed groups. Kruskal–Wallis test with post hoc

Dunnett's test (*p < 0.05; **p < 0.01）

图3不同品种组的皮肤含水量、pH值和皮脂水平(a)比格犬的皮肤含水量显著高于马尔济斯犬（p = 0.049）和迷你贵宾犬（p < 0.001）。(b)比格犬的pH值也显著高于马尔济斯犬（p = 0.008）和迷你贵宾犬（p < 0.001）。(c)不同品种组间皮脂水平无显著差异。Kruskal-Wallis检验与事后Dunnett检验(*p < 0.05；**p < 0.01)

 

 

FIGURE 4 Correlation between biophysical parameters (skin hydration, pH and sebum levels). A positive correlation was observed between skin hydration and pH. Spearman's rho (**p < 0.001; r = 0.403).

图4生物物理参数（皮肤含水量、pH值和皮脂水平）的相关性皮肤含水量与ph呈正相关。Spearman's rho (**p < 0.001；R = 0.403)。

 

 

杨先生

南海

学习

南海

学习

南海