A Study of the Effects of Phonophoretic Application of Hydrocortisone on the Regeneration of Injuries to Skeletal Muscle

The penetration of a topically applied compound (usually a cortisone containing solution or gel) for treatment of injured tissues can be improved by the use of ultrasound, a method known as phonophoresis. Therapeutic effects of the ultrasound itself are thought to contribute to the healing process as well [1,2]. However the mechanism of action of such a procedure remains poorly understood. In this work we have studied the cellular composition of the inflammatory infiltrate involved in the reaction to injury, and its modifications in the presence of ultrasound, hydrocortisone and the phonophoretic combination of the two treatments. Twenty whistar rats were divided into two groups of 10 rats. Rats were surgically injured by laceration according to [3]. Control rats (group I) were left to recover without any treatment. The experimental group (II) was treated with hydrocortisone 1% in gel (®Berlison, Laboratory Intendis of Brazil), conjugated with phonophoresis according to McElnay, 1987 [2]. Treatments were applied daily during the first 10 days after injury. Animals were sacrificed at 10 days after the injury. The specimens were studied with histological methods (H+E) (Fig. 1) and the composition of the inflamatory infiltrate was studied and cells identified using an oil immersion 100x objective, and counted with the help of the software ImageJ using the Cell Counter plugin designed by Kurt De Vos [4]. These plugins were designed in java to complement ImageJ image processing and analysis to count different cell types in histological sections [5].