A Study On The Changes Of The Density Of Skin Small Nerve Fibers And Microvascular Function In Patients With Dermatomyositis

Objective: 1.To establish the methodology of skin nerve biopsy.2.To investigate the pathological changes of skin microvascular endothelial cells and skin small nerve fibers in patients with dermatomyositis,and provide new ideas for the diagnosis of dermatomyositis with peripheral neuropathy.Methods: Skin biopsy was performed on 12 patients with dermato myositis.Three healthy volunteers were selected as controls.All skin sp ecimens were studied with routine histopathological staining and immuno histopathological staining with primary antibodies against endothelial nitri c oxide synthase(e NOS)and thrombomodulin(TM).For test the intraep idermal nerve fiber density(IENFD),immunohistopathological staining fo r protein gene product 9.5(PGP9.5)was also done in the skin biopsy s pecimens.Results: 1.Using PGP9.5 to label nerve fibers,we could see that th ere are abundant nerve fibers in epidermis,dermis and skin appendages of normal people.2.Compared with healthy volunteers,12 patients with dermatomyositis showed a decrease in IENFD,and the difference was statistically significant.NCV examination of all patients with dermatomy ositis showed normal.Immunohistochemistry showed that e NOS and T M expression on the vascular endothelial cells were decreased.Conclusions: 1.The skin nerve biopsy technique is simple and safe.It has the advantages of convenient material acquisition,low invasivene ss,and quantitative indicators.It can directly observe the pathological c hanges of small diameter nerve fibers in the skin under the microscope,making up for the current diagnosis of small fiber neuropathy by elect rophysiological examination Not sensitive enough.2.Before the damage of large nerve fibers without electrophysiological support,the patients with dermatomyositis may have the decrease of the density of small ner ve fibers in the skin and the dysfunction of skin microvascular endothel ial cells.