ENGLISH VERSION

Ireneusz Balicki
Research on diagnostics and treatment of chronic superficial 
keratitis in dogs

Chronic superficial keratitis often occurs in dogs and it can lead to the vision skill limitation and even blindness. The illness proceeds with the symptoms of blood vessels ingrowing, infiltration of the fibro-vascular tissue and the corneal pigmentation. The reason for chronic superficial keratitis is still unknown. Some authors think that it is an immunological based illness. The main environmental factor, which is of great importance in etiology of the illness is known to be the UV radiation. The patients suffering from the disease are ill for all their lives. In spite of clinical symptom disappearance many of them show the illness progression.

The purposes of the study were:

a) application ophthalmological eye drops – 50% DSMO in the treatment of chronic superficial keratitis and comparison of the results both with prednisolone therapy and the method of concurrent prednisolone and DSMO treatment,

b) comparison of treatment continuation effects with eye drops – 50% solution DMSO to 0.75% cyclosporine given simultaneously with 50% DMSO eye drops in 8 month period,

c) application of impressive cytology to diagnose chronic superficial keratitis, monitoring of pathological changes process, as well as estimation of DMSO and cyclosporine influence on anterior cornea epithelial cells,

d) determination of some chosen indexes of lipid and protein peroxidation as well as parameters of healthy German shepherds and their half-breeds antioxidant state, followed by their comparison with dogs showing chronic superficial keratitis.

Cytological and clinical study was performed in 79 dogs – 55 male and 24 bitches, aged 2-10 years and body mass 11- 54 kg . In order to confirm appearance of chronic superficial keratitis the patients were given a full ophthalmologic examination. Then they were divided into three groups depending on the way of treatment. In the group I there was administered Prednisolone 0.5% (Polfa). The patients of group II were treated with ophthalmologic eye drops containing 50% DMSO solution while the patients group III obtained Prednisolone 0.5% and 50% DMSO. The medicines were administered to the conjunctival sac in all groups, five times a day for 3 weeks. After this period if the inflammatory infiltration retreated and the pigmentation decreased, the treatment was continued with eye drops containing 50% DMSO or 0.75% cyclosporine and 50% DMSO, which were used for 8 months. In the other cases the dogs were treated by other pharmacological methods or they were operated on. The assessment of the particular group treatment results was performed by photography using a calibrated net. The area of the cornea involved in the pathological changes was estimated in per cents before the treatment and compared with the area after 5 week and then 8 month therapy.

The state of the anterior epithelial cells of cornea in ill dogs was estimated by impressive cytology performed with milipore filters. The preparations were stained by method called PAS.

The study showed that in the investigated dog population chronic superficial keratitis occurs in animals between 4 and 8 year of life and concerns 69.6% male. After counting the mean area of pathological changed cornea before treatment and comparing it with the one after 5 week therapy it was found that the greatest inflammatory infiltration disappearance was obtained in the group of dogs treated with prednisolone and DMSO simultaneously and the smallest one in the patients treated with DMSO only. It allows to affirm that concurrent giving 0.5% prednisolone and 50% DMSO as ophthalmological eye drops is the effective method of chronic superficial keratitis therapy, which can be continued by using DSMO or DSMO and cyclosporine in order to withdraw the illness symptoms. The concurrent cyclosporine and DMSO application was more efficient in preventing the disease progression then the application of DMSO only.

In the impressive cytology preparations which were obtained from the patients with chronic superficial keratitis, there was found, in the neighbourhood of the epithelial cells, an inflammatory infiltration with various intensification. The infiltration was built of mononuclear cells, mainly limphocytes and plasmatic ones. In the cytoplasm of the epithelial cells fine grained deposits of a pigment were observed. They were also presented in the form of thinner or thicker clusters outside the cell cytoplasm.

The study allows to affirm that the impressive cytology is both easy to be done and a non-invasive method, which can be used to diagnose chronic superficial keratitis. Application of this method enables to study dynamics of the pathological processes. Both clinical studies and estimation of corneal cells by application of impressive cytology did not show any harmful influence of cyclosporine and DMSO while applying them into conjunctive sacks for 8 months.

The estimation of the chosen lipid and protein peroxidation indexes as well as antioxidant state was performed in 64 dogs, divided into 4 groups. The first two groups involved German shepherds and half-breed dogs with recognized chronic superficial keratitis. Two other control groups included healthy German shepherds and healthy half-breeds.

The following parameters were determined in blood samples: malonic aldehyde (MDA), bityrosine, formylkinurenine, SH-groups, superoxide dismutase (SOD), glutathion peroxidase (GSH-Px) and total antioxidant capacity by using ferric reducing ability of plasma and vitamin E.

The studies did not show any differences in oxidants/antioxidants parameters between healthy half-breeds and healthy German shepherds.

Decrease of vitamin E concentration in the patients in contrast to increase of SOD, GSH-Px and overall antioxidant capacity as well as increasing in MDA, bityrosine and formylkinurenine can prove that in dogs with chronic superficial keratitis may have appeared the oxidative stress.