Eye (1989) 3, 840--844 Differential Staining of Ocular Goblet Cells G. G. W. ADAMS and P. N. DILLY London Summary Millipore filters were used to obtain sheets of cells from the ocular surface. Using Periodic Acid SchitT-haematoxylinthe intracellular neutral mucus of the goblet c-ells stains a brilliant, bright pink and the cell nuclei dark blue making it possible to observe the epithelial cells and the goblet cell population. In certain ocular surface diseases the size of the PAS-haematoxylin staining goblet cell population is reduced, returning towards normal as ocular health improves. These observations had previously been interpreted as showing degeneration fol­ lowed by regeneration of the goblet cells. However, Alcian blue stains an acidic mucus, which does not stain with PAS­ haematoxylin. Acidic mucus containing goblet cells have been revealed using Alcian blue staining when added to the PAS stained cells in conditions that have previously been shown to have reduced goblet cell population when assessed by PAS-haematox­ ylin staining. This suggests that the staining properties of some of the goblet cells have changed. The extra goblet cells revealed by Alcian Blue staining makes the total of goblet cells present close to normal in numbers. Improved clearing methods and cytological preservation has revealed that there is also a population of goblet cells that do not stain with either technique. These observations must cast doubts on pre­ vious claims of reduced goblet cell populations associated with some extraocular diseases. The use of filters for diagnostic cytology was Nelson and Wright developed a classifi­ first described in 1967.1 The filter technique cation for these surface cytology specimens, was an advantage because the filterswere easy based on epithelial cell morphology and gob­ to handle and mount, and they were let cell density.3 They used PAS-Haematoxy­ unaffected by most fixatives and stains. They lin as their routine stain. With this technique were found to be useful in the examination of the goblet cells were identifiedby the brilliant a wide range of body fluids, aspirates and pink staining of their intracellular mucin. washes. The use of Millipore filters on the Conjunctival goblet cell density is said to be ocular surface to perform a simple conjunc­ fairly constant and not to drop with age, tival biopsy was first described by Egbert and although it is known to decrease in diseases Maurice in 1977.2 associated with a loss of vascularisation or This technique of impression cytology has inflammation. The reason for this is unclear proved a simple and atraumatic procedure but it has been suggested that a blood borne that removes parts of the surface layer of cells factor may be important in goblet cell dif­ from the ocular surface and includes a good ferentiation and maintenance. This argument sample of goblet cells in the layer (Fig. 1). is supported by the fact that the avascular cor- Correspondence to: GGW Adams, Department of Anatomy, St. George's Hospital Medical School, Tooting, London SW17 ORE. DIFFERENTIAL STAINING OF OCULAR GOBLET CELLS 841 Fig. 2. Same sample as Figure 1 with PAS­ Fig. 1. PAS-haematoxylin stained cells showing haematoxylin and Alcian blue stained cells showing normal cytolbgy and a high density of goblet cells. goblet cells containing pink and blue staining mucus. Bar=l00fAm. Bar=JOOfAm. nea does not have goblet cells, and it is poss­ removed by soaking in xylene. The previous ible to transform the morphology of stains were removed by soaking in 70% indus­ conjunctival epithelium to that resembling trial methylated spirit and hydrochloric acid corneal epithelium by reducing its blood until the dye was leached out of the filter supply and vice versa. 4 papers. The filters were then rehydrated, Recently we took samples for examination stained in 1% Alcian Blue in 3% acetic acid of possible malignant change in a patient's for one minute, rinsed and stained with conjunctiva. Our. cytopathologist stained periodic acid, followed by Schiff's reagent, these specimens with a variety of dyes, includ­ and haematoxylin, before being dehydrated, ing Alcian Blue. In these slides we saw blue cleared in xylene and mounted on slides using staining mucus, as well as the characteristic Eukitt mounting reagent (0. Kindler, West pink of PAS-haematoxylin stained mucus in Germany). obvious goblet cells. This then led us to re­ Results examine some. of our previous slides. We Staining the sheets of cells obtained from the found unstained goblet cells that appeared to conjunctiva by impression cytology with the be full, but were not staining with PAS-hae­ standard P AS-Haematoxylin technique matoxylin and Alcian Blue and we found that reveals the epithelial cells and goblet cells. some of the previously non-staining goblet The intracellular mucus of the goblet cells cells were now stained with Alcian Blue (Fig. 2). stains a brilliant, bright pink. All goblet cells are said to stain with PAS-haematoxylin, Materials and Method which demonstrates the side chain sugar mol­ Samples were taken from the conjunctiva as ecules of the mucus glycoprotein.6 This stain­ previously described.s Samples from eleven ing identifies the neutral mucus within the patients pre- and post-Botulinum toxin pro­ conjunctival goblet cells. As well as this neu­ tective ptosis (BTPP) were obtained using tral mucus some cells from other regions of impression cytology. Samples were also the body have been reported to produce an obtained from -seven patients with suppura­ acid mucus. The acid mucus can be demon­ tive keratitis over the course of the disease strated using the Alcian blue technique. process, from six patients with uveitis, and Using the PAS-haematoxylin-Alcian blue from four patients with alkali injuries. techniques we re-examined samples from Samples were normally taken from four sites patients with alkali burns, BTPP, uveitis and in each patient: medial and lateral interpal­ suppurative keratitis in whom we had found a pebral conjunctiva, inferior bulbar conjunc­ loss or reduction in goblet cell density on tiva and superior tarsal plate after eversion of PAS-haematoxylin stallllllg. We found the upper lid. The cover slips from the slides samples where PAS-Haematoxylin staining that had previously been stained were had not demonstrated all the goblet cells con- 842 G. G. W. ADAMS AND P. N. DILLY taining mucus as we could see full goblet cells face disease requiring botulinum toxin pro­ without PAS staining of the intracellular tective ptosis (Figs. 7,8,9) and most obviously mucus. in samples from patients with uveitis (Figs. This was seen in alkali burns (Figs. 3,4), 10,11). We found some goblet cells that were suppurative keratitis (Figs. 5,6), corneal sur- non staining with either PAS-haematoxylin or Fig. 3. PAS-haematoxylin stained cells in alkali burn. Fig. 6. Same sample as Figure 5 with PAS­ Many pale areas containing non-staining goblet cells haematoxylin and Aldan blue stained cells in can be seen. Bar=l00[tm. suppurative keratitis. Both pink and blue staining goblet cells are visible. Bar=100[tm. Fig. 7. PAS-haematoxylin stained cells in Botulinum Fig. 4. Same sample as Figure 3 with PAS­ toxin induced protective ptosis for indolent corneal haematoxylin and Alcian blue stained cells in alkali ulceration. Polymorphs can be seen between cells. burn showing neutral and acidic staining mucus. Bar=lOO[tm. Bar=l00[tm. Fig. 8. Same sample as Figure 7 with PAS­ haematoxylin and Aldan blue stained cells in Fig. 5. PAS-haematoxylin stained cells in suppurative Botulinum toxin induced protective ptosis. Goblet cells keratitis with no obvious goblet cell staining. containing pink and blue mucus can be seen Bar=l00o,un. Bar=100[tm. DIFFERENTIAL STAINING OF OCULAR GOBLET CELLS 843 Fig. 10. PAS-haematoxylin stained cells in uveitis. No Fig. 9. Higher resolution of Figure 8 to show pink and obvious goblet cells stained. Bar=]OOIIDl. blue mucus with greater definition. Bar=251ID1. Fig. 11. Same sample as Figure ]0 with PAS­ Fig. 12. PAS-haematoxylin and Alcian blue stained haematoxylin and Aldan blue stained cells in uveitis. cells with pink and blue staining mucus and a non­ Note the goblet cells containing blue staining mucus. staining goblet cell. Non-staining goblet cell. Non­ Bar=]OOtJ.m. staining goblet cell arrowed. Bar=251ID1. PAS-haematoxylin-Alcian blue (Fig. 11). In face vesicles, in association with increased some goblet cells the mucus within the cell mucus production.9 boundaries was stained pink, whereas that A trend to sulphation of mucus is said to be spreading from the cell on the conjunctival associated with a tendency to inflammation surface stained blue and conjunctival metaplasia.6 A change in the chemical composition of certain types of Discussion mucus influencesthe rheological properties of Conjunctival mucus is important in corneal mucin and presumably different staining wetting, and it is a major factor in spreading properties reveals some evidence for differing the pre-corneal tear film over the ocular sur­ physico-chemical properties.11 Excess mucus face.7 Mucus is produced by the goblet cells production can lead to tear instability and which are normally present in the superficial abnormal mucus can produce filamentary and middle layers of the conjunctiva, and by keratitis and mucous plaques. A specific pat­ the sub-surface vesicles that are found just tern of mucus production would therefore below the surface of the conjunctival cells.8 seem to be required for ocular comfort and The mucus produced by the sub-surface ves­ health. icles anchors the 'goblet cell mucus layer onto It has been shown that goblet cells of the the ocular surface, by way of glycoprotein conjunctiva produce a neutral mucin and at chains. In certain ocular surface diseases such least four differing types of acid mucus.6 PAS as anaesthetic cornea, giant papillary con­ stains neutral mucus pink, whilst Alcian blue junctivitis, and asymptomatic contact lens at pH3 will show acid muco-substances, which wearers, there is an increase in these subsur- stain blue.1O It has been said that all goblet 844 G.