The authors studied the alteration of the gait and the tissue reaction of the muscle which got an endopeels injection.
We chose to apply endopeel into the pre tibial muscle of rats and study the histological alterations.
The choice of the pre tibial muscle of rats was made because of similarity as weight with the depressor muscle of the corner of the mouth in humans.
Objective : Study the biological phenomenon caused by the endopeels injection into the pre tibial muscle of the Wister Rat and evaluate the alterations in its gait and the histopathological alteration in the applied muscle.
To register the footprints of the rats, strips of paper measuring 43 cm long by 8.7 wide, sizes that are considered as being adequate for the rats ‘catwalk’ and built as per the De MEDINACELI; FREED; WYATT (1982) drawing. The paper was previously soaked in a solution of bromophenol blue were used.
For the preparation of the paper the bromophenol blue in its anhydrous (Sigma) form was diluted in at 1% in absolute acetone, acquiring an orange color.
The sheets of paper were soaked in this solution and placed in the sun to dry, then they were cut into strips and stored in plastic packages, so as to avoid humidity, which could alter the blue color.
The animals were made to walk on the catwalk covered with the previously prepared paper strips, with their hind legs soaked in a solution of neutral detergent, which immediately changes the color of the footprint from yellow to blue . The footprints remain on the paper strips, which were left to dry for the reading of the necessary measures to calculate the Sciatic Functional Index .
Later these were analyzed by a computer program (software) developed by SELLI (1998) , to obtain the Sciatic Functional Index that was proposed by BAIN; MACKINNON; HUNTER (1989), which takes into account the print length, the total toe spread between the 1st to the 4th toe, and the intermediate toes which are the 2nd and 3rd. The footprints of each animal were obtained before the application of endopeel, as a control, and immediately after the endopeel injection, and again, and at periodic intervals, when the animals were sacrificed for the extraction of the anterior tibia muscle for histological study.
The footprints were digitalized with a scanner and placed into the SELLI program, which allows for the capture, identification and analysis of the images, allowing for the application of other methods of identification of the Sciatic Functional Index (DE MEDINACELI, FREED & WYATT, 1982; DE MEDINACELI, DERENZO & WYATT, 1984; CARLTON & GOLDBERG, 1986), as well as Tibia Functionality indexes and the peroneal nerve (BAIN; MACKINNON & HUNTER, 1989). Once the footprint is shown on the monitor, its parameters are analyzed and measured, which require the placing of the cursor to be clicked in the correct predetermined sequence. The program then calculates and supplies the value of the index, and this is also stored in the computer.
Footprints of the mouse after 0.05 ml injection in the right pre tibial muscle
Schematic representation of the measurements realized to calculate the Sciatic Functional Index.
E: Experimental (operated foot);
N: Normal (opposite foot);
TS: Total opening of the toes (1st to 5th);
IT: Opening of the intermediate toes (2nd to 4th);
PL: Length of footstep
NaCl 0.9%, 0.1 ml into the pretibial muscle does not alter the gait.
The alteration in the gait caused by Endopeel decreases with time when applied via intramuscular, at this level of concentration.