Abstract
Corticosteroid induced histological changes were studied in the skin of the guinea pig. Betamethasone-17-valerate (0.1%) ointment was applied twice daily to a small area of animal's dorsal skin. Skin samples were excised from the treated areas every week for four weeks. Histological study was carried out under light micro-scope. The study revealed mild atrophic changes in the skin after the 4th week.
INTRODUCTION
Corticosteroid induced cutaneous atro-phy is a well recognised feature of prolonged topical use of potent corticosteroids. Although the original phenomenon was de-scribed by Epstein et at (1963) yet the ex-peiimentzti evidence in this area was not forthcoming until recently. To establish a minimum time scale for inducing skin atro-phy with a potent topical corticosteroid that would accomplish its safe usage, the experi-ment under report was carried out.
MATERIALS AND METHODS
Male Albino guinea pigs weighing 500 ± 25 g were shaved on the back with electric clippers. They were stabilized in individual cages. All animals received green fodder crushed grams and water ad libitum. The animals were divided into two groups A and B. The group A animals were applied be-tamethasone-17-valerate (0.1%) ointment, while group B acted as a control and re-ceived the base or the vehicle of the oint-ment. For a period of 4 weeks 0.2 ml of the ointment and the base was applied to 5 cm' area on the back of the animals with a glass rod, twice daily at 8.00 a.m. and then at 7.30 p.m. Four animals from each group were
killed at the end of every week. Full thick-ness skin from the test area was excised, processed and embedded in paraffin, sec-tioned at 06 u vertically and studied with I-1 and E, Van Gieson and Gomori's rapid one step trichrome stain. For overall histological evaluation, the point scale was used (Jablonska et al., 1979).
RESULTS
Table 1 indicates mild epidermal atro-phy after 4 weeks topical application of be-tamethasone-17-valerate (0.1%) ointment. The dermal histology does not show any ap-preciable changes. The characteristic feature of thinned epidermis was the flattening or even complete disappearance of rete ridges. In some cases, the epidermis was composed of not more than a few layers. The reduction in number was accompanied by a decrease in size of the cells. In some sections basal cells were cuhoidal in shape. Epidermal changes were often associated with signs of disordered keratinization and nuclear rem-nants were present in the stratum corneum. Thinning of reticular layer of dermis was ob-served in some sections. The. collagen bun-dles were also thin and lightly stained. Hair follicles and sebaceous glands did not show any effect.
