Effects of chymotrypsin in experimental crushing injury and inflammation in rats
Kunitz and Northrop first crystallized trypsin in 1931 and chymotrypsin in 1933.
This proteolytic enzymes are increasing and have been widely employed clinically as anti-inflammatory and antiedemic remedies.
Innerfield (1952) observed that intravenously administrated trypsin induced lytic effects on artificially formed intravascular thrombi in animal experiments. Keirls (1960) dissolved thrombi in dog extremities using 100,000 to 500,000 units of the enzyme by the isolation perfusion technique. Martin (1954) established that the production of egg white edema in rabbits was inhibited by parenteral administration of either trypsion or chymotrypsin. He concluded that these anti-inflammatory and anti-edemic effect might be due to their proteolytic activities. Cohen (1955) demonatrated that dextran edema was prevented by pretreatment with trypsin and chymotrypsin. and post-edema treatment with the proteolytic enzymes caused a regression or diminution of the edema. Miechowski (1956) made a comparison between trypsin and chymotrypsin of inflammatory responses of various types. The quantitative comparison of their activities indicated that
chymotrypsin on the basis of proteolytic unitage, possesses a significantly greater anti-inflammatory effect than trypsin. Davis (1959) pointed out that chymotrypsin has two mechanisms. One acts immediately by depressing inflammation and inhibiting
further inflammation, and the other is a delayed mechanism of anti-coagulation.
Allaben (1962) showed that when chymotrypsin is given in large dose intramuscularly it reduces edema in rhesus monkeys. The maximum degree of edema reached was less than that in control animals, and reduction of edema began sooner and was completed
more rapidly in the treated animals. Evaluation of anti- inflammatory and anti-edemic effects of chymotrypsin in the clinical cases of Cetrulo (1953) and Cigarroa (1960) confirm that this proteolytic enzymes prevents or reduces objective and subjective signs of inflammation.
In this paper the systemic and local effects of chymotrypsin on crushing injury and formaldehyde induced inflammation are presented.
One hundred young albino rats (Sprague-Dawly strain), around 150 gm., were used.
They were divded into two groups one with crushing injury and the other of inflammation with 50 rats in each group. Each group was then subdivided into five treatment group as follows:
1. Control group
2. Small dosage group
3. Large dosage group
4. short term group
5. Pretreated group
Edema was produced by trauma, such as crushing the foot with a compression machine, the amount of pressure being the same throughout the experiment. Acute inflammation was induced by subcutaneous injection into the dorsum of the foot of 0.05 ml. of 0.35% solution of formaldehyde in normal saline (Northover and
Subramanian's method) in the inflammation group. Rats in the control group were given 0.05ml. of normal saline, in the small dosage group 150 units per kilogram of chymotrypsin and in the large dosage group 750 units per kilogram intramuscularly twice a day for seven days. The rats of short term group were given 750 units per kilogram twice for one day only. The pretreated group received 750 units per kilogram of chymotrypsin twice a day 24 hours before the induction of edema, and then had no further treatment with the drug. The mean response for swelling in the
member of each group was calculated by measurement of diameter of the foot, body weight, and temperature, as well as observation of systemic changes during the 21 days of the experiment. Three of each group sacrificed at 21 days and histological examination of the involved foot was made.
The result of the experiment are as follows:
1. Chymotrypsin prevented and reduced edema significantly.
2. On histological study chymotrypsin showed a anti-flammatory effect. Infiltration of inflammatory cell and connective tissue proliferation in the tissues was much less than in untreated animals.
3. anti-edemic and anti-inflammatory effects of chymotrypsin were marked with large dose, and greatest on the first day of treatment.
4. Pretreatment with chymotrypsin prevented the production of edema and inflammation.
5. Chymotrypsin had no significant effect on body weight or temperature and produced no other systemic or local effects throughout the experiment.
In conclusion, the chymotrypsin has an anti-inflammatory and anti-edemic effect especially in large dosage. The importance of initial first day effect is emphasized. In the clinical application of chymotrypsin, the maximum anti-edemic effects can be expected in large dosage for short term administration of this drug.