Angiostasis and Vascular Regression in Chronic Granulomatous Inflammation Induced by Diclofenac in Combination with Hyaluronan in Mice

Abstract

Angiostasis and vascular regression in chronic granulomatous inflammation was assessed in mice induced with diclofenac in combination with hyaluronan. The local injection of 0·1 mL HYAL EX-0001 (0·18% diclofenac in 2·5% hyaluronan) reduced granulomatous development after six days treatment from 150·4 ± 13·8 (0·18 saline) to 117·1 ± 17·8 mg (dry weight, n = 10), but not significantly when compared with 0·1 mL 2·5% hyaluronan alone or diclofenac in 0·1 mL saline. Diclofenac administered in saline had no significant effect when compared with saline control. The vascular density, expressed as carmine content per mg dry weight tissue, in those animals treated with HYAL EX-0001 was also significantly reduced to 5·27 ± 0·55 μg mg−1 (P < 0·1, n = 10) when compared with saline control (7·99 ± 1·0), hyaluronan alone (7·20 ± 1·0), and diclofenac in saline. (7·36 ± 1·28). A similar profile of activity was seen on topical application except that all treatments did not affect granulomatous tissue development. On therapeutic dosing of mice daily with HYAL EX-0001 from day 7 after induction of the granulomatous tissue, the granulomatous tissue development was dramatically reduced from 111·67 ± 4·40 mg (n = 14 on day 7) to 60·23 ± 7·22 (P < 0·001, n = 8 on day 14) and 54·98 ± 7·88 (P < 0·001, n = 8 on day 21). HYAL EX-0001 after 14 days of application significantly reduced granulomatous tissue mass when compared with the hyaluronan-dosed control on day 21 (89·58 ± 7·49, P = 0·01, n = 8). The granulomatous tissue lost weight on the application of hyaluronan for 14 days by 19·8% (P < 0·01). The vascular density of the tissues was 15·05 ± 0·63 μg mg−1, which HYAL EX-0001 significantly reduced to 11·96 ± 1·14 (P < 0·05) after 7 days application and 11·25 ± 1·21 μg mg−1 (P < 0·02) after 14 days application. The latter was significantly inhibited when compared with the day 21 hyaluronan control (14·02 ± 1·39 μg mg−1, P < 0·05). The day 7 vascular density was not significantly reduced by the topical application of hyaluronan from day 7 to 21. The results suggest that hyaluronan is acting as a novel and effective drug delivery system, and may explain the therapeutic effectiveness of HYAL CT-1101 on basal cell carcinoma and actinic keratosis.