Tna JOURNAL OF INVESTIGATIVE DERMATOLOGY

Copyright 1965 by The Williams & Wilkins Co.Vol. 45, No. 3

Printed in U.S.A.

Preliminary and Short Report

LACTIC DEHYDROGENASE ACTIVITY IN ORALLICHEN PLANES LESIONSE

GERALD SHKLAR, D.D.S., MS.

The classical microscopic features of lichenplanus have been recognized for many years (1).Oral mucosal lesions in lichen planus are extremelycommon, and the histopathology of the oral mu-cosal lesions is comparable to that of skin lesions(2—5). The main features of the oral lesions areparakeratosis or hyperkeratosis, hydropic degener-ation of the stratum germinativum of the epithe-hum, and an inflammatory infiltration of the un-derlying connective tissue (Fig. 1). The infiltrateis composed primarily of lymphocytes and appearsas a broad band directly beneath the stratum ger-minativum of the mucosal epithelium. The deeperlayers of the connective tissue are relatively freeof inflammatory cells, although dilated capillariesmay be observed. Because of the location of theinflammatory infiltrate and the hydropic degenera-tion of the basal layer, there is often a hazy or in-distinct demarcation between epithelium and un-derlying connective tissue. Occasionally there maybe some downward extension of the epitbelial retepegs, although the 'saw tooth' configuration seenin lesions is not commonly observed in oral le-sions. In addition to the parakeratosis or hyper-keratosis, there may be slight to moderate acan-thosis. In some oral lesions, the widened stratumcorneum is represented by parakeratosis, while inother cases there may be hyperkeratosis or a mix-ture of alternating zones of hyperkeratosis andparakeratosis. In some cases of oral lichen planus,the hydropic degeneration may be so severe, thatsubepithelial vesicles are formed and the clinicallesions may develop into a bullous or erosive pat-tern. Dysplasia or dyskeratosis is not a feature oforal lichen planus lesions.

In cases where lesions are confined to the oralmucosa, diagnosis cannot be made in terms of his-topathology alone. There must be a correlation ofboth clinical and microscopic evidence. The orallesions of lichen planus may present a microscopicpicture of nonspecific chronic inflammation. Le-sions that may present no microscopic evidence oflichen planus, often develop at a later stage intothe classical histologic pattern. For this reason,many histopathologists prefer to offer a micro-scopic description of 'chronic inflammation con-sistent with a diagnosis of lichen planus' ratherthan a specific microscopic diagnosis. A negativemicroscopic report, furthermore, does not rule out

This project was supported by Grant DE 01861-02, National Institutes of Health.

Received for publication April 6, 1965.* From the Department of Oral Pathology, Tufts

University School of Dental Medicine, Boston,Massachusetts.

the possibility of lichen planus, since many caseswith classical clinical manifestations present a clas-sic microscopic pattern only late in the course ofthe disease, or not at all.

Since the microscopic features of lichen planusoften present diagnostic problems, and since theetiology and patbogenesis of this interesting condi-tion is still not fully understood, various histo-chemical studies have been undertaken in an at-tempt to clarify some of these problems. Using theperiodic acid-Schiff technic for the demonstrationof mucopolysaccharides, the basement membranehas been found to be clearly and sharply definedbut relatively thin. The epithelial cells were foundto be relatively free of mucopolysaccharides, butthe zone of parakeratosis often stained deeply (5).

With the development of standard technics forthe preparation of fresh histologic specimens, andwith the development of refined technics for thedemonstration of specific enzyme activity in tis-sues (6—8), it was decided to investigate oral lesionsof lichen planus for their enzyme patterns. Thisreport is concerned with lactic dehydrogenase ac-tivity in normal oral mucosa and in oral lesions oflichen planus.

MATERIALS AND METHODS

Ten biopsy specimens of 'normal' uninflamed andinflamed oral mucosa were studied in addition tosix biopsy specimens of lichen planus. The casesof lichen planus presented characteristic clinicalfeatures, and previous biopsy specimens, fixed informahin and stained with hematoxylin-cosin pre-sented classical microscopic patterns consistentwith a diagnosis of lichen planus. The lesions oflichen planus were present on buccal mucosa infive cases and gingiva in one case. Specimens ofnormal mucosa represented buccal mucosa, gingiva,and palate.

The biopsy specimens were placed in the freez-ing compartment of a cryostat within 15 minutesafter removal. They were brought to the labora-tory in physiological saline solution. The tissueswere sectioned in the cryostat at 10 microns andprepared for the demonstration of lactic dehydro-genase activity, using the technic outlined by Ogataand Mon (9). The substrate was sodium lactateand Nitro Blue Tetrazohium with DPN. A Phos-phate buffer was used to adjust the substrate to apH of 7.4. Sections were mounted in glycerogel.

220

OBSERVATIONS

Normol Ocol Mucose

Epithelium: In relatively normal oral mucosa,there was slight to moderate lactic dehydrogenase

LACTIC DEHYDROGENASE ACTIVITY IN ORAL LICHEN PLANUS 221.

Fie. 1. Lesions of oral lichen planus demonstrating the classical microscopic features ofparakeratosis, hydropie degeneration of stratum germinativum, and chronic inflammatoryinfiltration localized as a band beneath the epithelium. (Hematoxylin-eosin >< 65.S)

activity. The major activity was within the cyto-plasm of cells of the stratum germinativum andstratum spinosum. Where the epithelium presenteda well defined stratum corneum or a degree of hy-perkeratosis, the stratum corneum and stratumgranulosum were nonreactive for lactic dehydro-genase activity (Fig. 2). Where there was somedownward extension of rete pegs, there was a sug-gestion of increased enzyme activity along thebasal layer of the hyperplastic epithelial pegs (Fig.2).

Connective tissue: Slight enzyme activity wasnoted within the eorium. Where some moderateactivity was seen, it appeared to be related to theperiphery of small capillaries, to inflammatory cellsand to some connective tissue fibers.

Inflamed Oral Mucose

Epithelium: In oral mucosa affected by irrita-tional influences and involved with chronic inflam-mation, there is a generalized slight increase inlactic dehydrogenase activity. The surface keratin-ization is often absent in these areas and the en-tire width of the stratified squamous epithelium

demonstrates moderate enzyme activity in the cy-toplasm of the cells. The rete pegs may presentsignificant downward extension in inflamed mu-cosa, and the basement membrane zone often ap-pears to demonstrate a thin line of increased lacticdehydrogenase activity (Fig. 3).

Connective tissue: The connective tissue pre-sents lactic dehydrogenase activity in the zones ofdense lymphocytic infiltration (Fig. 3). Some ac-tivity appears to be related to some connectivetissue fibers, since a fibrillar pattern may be ap-parent.

Oral Lichen PlanusEpithelium: Although the number of oral lichen

planus tissues studied is small, the findings wereessentially similar in all eases. There was a notableincrease in lactic dehydrogenase activity through-out the entire width of epithehum and a markedaccentuation of enzyme activity as the stratumgerminativum or basal layers (Fig. 4, 5). Theparakeratotic zone at the surface tended towardmoderate activity.

Connective tissue: The connective tissue was

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222 THE JOURNAL OF INVESTIGATIVE DERMATOLOGY

FIG. 2. Normal oral mucosa prepared for the demonstration of lactic dehydrogenaseactivity. The stratum corneum and stratum granulosum are non-reactive. The cytoplasmof cells of the stratum spinosum and stratum germinativum is moderately reactive. Slightlyincreased activity is noted in elongated rete pegs. (Substrate Sodium Lactate and NBTwith DPN X 200)

relatively negative for lactic dehydrogenase activ-ity. Some fibers were reactive and some strongreactivity occurred in areas of inflammatory infil-tration adjacent to the basal layer of the epithe-hum.

nIscussIoN

A marked difference was found between lacticdehydrogenase activity in oral lichen planus le-sions as compared to normal and chronically in-flamed oral mucosa. In addition to a generalized

increase in enzyme activity, there was a markedincrease localized to the area of the basal layer.This is not a surprising finding, since the maj orpathology in lichen planus lesions has been consid-ered by many investigators to be related to thebasal layer of the epithelium and the so-calledbasement membrane area directly beneath it. Thishistochemical confirmation of an altered metabo-lism in lichen planus lesions is of interest, particu-larly since an increase in lactic dehydrogenase ac-tivity is suggestive of an increase in glycolysis

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LACTIC DEHYDROGENASE ACTIVITY IN ORAL LICHEN PLANUS 223

FIG. 3. Inflamed oral mucosa prepared for the demonstration of lactic dehydrogenaseactivity: The entire epithehum is moderately reactive. Inflammatory cells within theunderlying connective tissue are reactive. (X 200)

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Fm. 4. Oral lichen planus prepared for the demonstration of lactic dehydrogenase ac-tivity. The entire epithelium presents increased enzyme activity and intense reactivity isnoted at the basal layer. Inflammatory cells in the connective tissue are also reactive.(X 200)

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LACTIC DEHYDROGENASE ACTIVITY IN ORAL LICHEN PLANTIS 225

FIG. 5. Oral lichen pianos lesion with marked parakeratosis and acanthosis. The entireepithelium is reactive for lactic dehydrogenase activity and intense reactivity is apparentat the basal layer. (X 200)

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226 THE J OTIENAL OF INVESTIGATIVE DERMATOLOGY

whereby glucose is metabolized anaerobically tolactic acid rather than aerobically to carbon diox-ide. Further histochemical studies are necessaryto evaluate the significance of these findings.

REFERENCES1. McCarthy, L.: Histopathology of Skin Diseases,

page 210. St. Louis, C. V. Mosby Co.. 1931.2. Dubreuilh, W.: Histologie du lichen plan des

muquesuses. Ann. Dermatol., 7: 123, 1906.3. Cooke, B. E. D.: The oral manifestations of

Lichen Planus: 50 Cases. Brit. Dent. J., 96:1, 1954.

4. Shklar, G. and McCarthy, P. L.: Oral Lesionsof Lichen Planus. Oral Surg., Oral Med., OralPath., 14: 164, 1961.

5. Shklar, G. and Meyer, I.: The histopathologyand histochemistry of dermatologic lesions inthe mouth. Oral Surg., Oral Med., Oral Path.,14: 1069, 1961.

6. Pearse, A. C. E.: Histochemistry, Theoreticaland Applied. page 580. Boston, Little Brownand Co., 1960.

7. Eichel, B.: Oxidative enzymes of gingiva. Ann.N. Y. Acad. Sci., 86: 479, 1960.

8. Kapur, K., Chauncey, H., Shapiro, S. andShklar, C.: A comparative study of the en-zyme histochemistry of human edentulousalveolar mucosa and gingival mucosa. Perio-dontics, 1: 137, 1963.

9. Ogata, T. and Mori, M.: Histoehemical studyof oxidative enzymes in vertebrate muscle.J. Histochem. Cytochem., 12: 171, 1964.