Effect of hyperbaric oxygen on the process of hypertrophic scar formation in rabbit ears

Summary

Objective

To explore the influence of hyperbaric oxygen on scar formation in rabbit ears.

Methods

A total of 20 New Zealand rabbits were selected to establish the hypertrophic scar model on the ears. The rabbits were randomly divided into control group and experimental group (7d, 14d, 21d, and 28d group according to different HBO treatment days),each experimental group received hyperbaric oxygen treatment after the operation at the same time everyday for 1 hour. After the day 29, the scars were collected. Histomorphological change in scars was observed by hematoxylin-eosin staining, Masson staining, and transmission electrical microscope. The expression of bax, bcl-2, and the cell apoptosis rate was detected by immunohistochemical method.

Results

(i) Both number of fibroblast and amount of collagen fibrils in experimental group were significantly reduced compared with those in control group. In Masson staining, arrangement of collagen fibrils in experimental group was much more irregular and coarse than control groups. (ii) HI value can be found much smaller in the experimental groups than the control (P < .05). Among the four experimental groups, there is significant difference among 7d, 14d, and 21d groups (P < .05), while there is no difference between 21d and 28d groups (P > .05). (iii) Expression of Bax could be detected up-regulated in experimental group (P < .05). While the expression of Bcl-2 is detected significantly down-regulated in experimental group than that in control group (P < .05). Compared with the 7d group, the expression of Bax and Bcl-2 has significant difference in 14d group (P < .05), and the expression of this two factors in 21d group has significant difference comparing with 14d group(P < .05),but there is no significant difference between 28d group and 21d group(P > .05). (iv) Significant difference of cell apoptosis rate can be detected between the experimental groups and the control group (P < .05). Among the four experimental groups, there is significant difference among 7d, 14d, and 21d groups (P < .05), while there is no difference between 21d and 28d groups (P > .05).

Conclusion

The hyperbaric oxygen can up-regulate bax/bcl-2 value, increase the cell apoptosis rate, and inhibit the early hypertrophic scar in rabbit ears.

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