大鼠头皮组织形态和生物力学参数的增龄性变化

Age-Related Changes in Histo-Morphological and Biomechanical Parameters of Scalp in Rats

目的:探讨大鼠头皮组织形态与生物力学参数的增龄性变化规律。方法:48只健康雄性SD大鼠按出生周龄分为2、4、6、8、17、26、52和104周组,大鼠麻醉后取头皮组织,10%中性甲醛溶液固定后进行HE染色,显微镜下观察其组织形态并测量厚度,同时利用电子万能材料试验机检测头皮的拉伸生物力学参数(极限载荷、拉伸强度和弹性模量)。结果:组织学结果显示,随年龄增长,大鼠头皮总厚度、表皮、真皮和皮下组织厚度逐渐增大,头皮总厚度和真皮层厚度26周时达高峰,之后趋于稳定,表皮与真皮比值变化不明显(P>0.05);生物力学检测发现,各组大鼠头皮极限载荷、拉伸强度随年龄增长呈逐渐增大趋势,弹性模量无明显变化;各组大鼠头皮的表皮、真皮、皮下组织的厚度及总厚度、头皮的极限载荷和拉伸强度均与年龄呈正相关(r>0且P<0.05),弹性模量与年龄不相关(r=0.290,P>0.05)。结论:大鼠头皮组织总厚度、真皮和皮下组织随年龄增长逐渐增厚,极限载荷、拉伸强度随年龄增长逐渐增大。

Objective:To explore the changes of age-related histo-morphological and biomechanical parameters of scalp in rats.Methods:A total of 48 male SD rats were divided into 2,4,6,8,17,26,52 and 104 week groups.Part of the scalp tissues was fixed with formalin solution and stained with HE,and their histo-morphological characteristics were observed under the microscope.At the same time,the ultimate load,tensile strength,elastic modulus of scalp specimens were measured by electronic universal material testing machine.Results:Morphological observation and detection showed that the total scalp thickness,epidermis,dermis and subcutaneous tissues of the rats gradually thickened with age,and the difference in mean values among the groups was statistically significant(P<0.05),while the ratio of epidermis to dermis did not change significantly(P>0.05).The tensile biomechanical test showed that the ultimate load and tensile strength of the scalp of each group increased gradually with age,and the elastic modulus increased first and then decreased,with statistically significant difference in each group(P<0.05).Scalp thickness,total thickness,ultimate load and tensile strength were positively correlated with age(r>0 and P<0.05),but elastic modulus was not related with age(P>0.05).Conclusion:The total thickness,dermis and subcutaneous tissues of rats scalp tissues gradually thicken with age,and the ultimate load and tensile strength gradually increase with age,which can provide reference for age inference.