OBJECTIVETo investigate the feasibility of prevention and treatment of early scar through observing the effect of feeding immunosuppressive drug cyclophosphamide on rabbit ears hypertrophic scar tissue in early stage.

METHODSThirty-two Rabbit ears were used to establish animal models for hypertrophic scar and randomly divided into four groups: group of distilled water (A), group of cyclophosphamide 5 mg x kg(-1) x d(-1) (B), group of 10 mg x kg(-1) x d(-1) (C), group of 30 mg x kg(-1) x d(-1) (D). Before animal models were built and after administration for 14 days, 28 days, leukocytes and lymphocytes were detected. After 28 days, specimens were harvested and underwent HE staining and VG staining in order to assess HI, NA, AA value changes. The data (HI, NA, AA) from each group were compared by analysis of variance, and the variance for the rank sum test when missing.

RESULTSOn the 14th day, the number of leukocytes in group A, B, C, D were (8.62 +/- 0.58) x 10(9)/L, (4.48 +/- 0.41) x 10(9)/L, (2.7 +/- 0.26) x 10(9)/L, (1.33 +/- 0.27) x 10(9)/L; the number of lymphocytes in group A, B, C, D were (3.11 +/- 0.21) x 10(9)/L, (1.67 +/- 0.16) x 10(9)/L, (0.42 +/- 0.10) x 10(9)/L, (0.40 +/- 0.09) x 10(9)/L. On the 28th day, the number of leukocytes in group A, B, C, D was (8.63 +/- 0.53) x 10(9)/L, (5.10 +/- 0.27) x 10(9)/L, (3.10 +/- 0.26) x 10(9)/L, (1.98 +/- 0.20) x 10(9)/L; the number of lymphocytes A, B, C, D was (3.06 +/- 0.16) x 10(9)/L, (2.08 +/- 0.14) x 10(9)/L, (0.96 +/- 0.19) x 10(9)/L, (0.14 +/- 0.07) x 10(9)/L. On the 14th day and 28th day, the number of leukocytes and lymphocytes in experimental groups was reduced, showing a negative relation with cyclophosphamide dose (P < 0.05). The HI in group of A, B, C, D was 3.02 +/- 0.24, 2.59 +/- 0.43, 2.06 +/- 0.19, 1.63 +/- 0.11; the AA was 40.49 +/- 2. 07, 35.29 +/- 1.99, 28.36 +/- 1.87, 24.99 +/- 1.82; the NA was 4570.5 +/- 259.3, 4222.5 +/- 199.6, 3540.3 +/- 170.3, 3341.4 +/- 228.8. The difference in HI, AA, NA between control group and any of the experimental groups was statistically significant (P < 0.01). Each group, with the dose increased, except NA content of group C and D, the HI, AA, NA was more smaller, negative correlation, the difference was statistically significant (P < 0.05).

CONCLUSIONSFeeding cyclophosphamide can inhibit leukocytes and lymphocytes number, so as to inhibit the proliferative activity of hypertrophic scar. It has significant effect on prevention of hypertrophic scar on rabbit ears in early stage.