Streaming of Proteolytic Enzyme Solutions for Wound Debridement: A Feasibility Study

Tali Yaakobi, PhD; Dalit Roth, MSc; Yoram Chen, BSc; Amihay Freeman, PhD

Disclosures

Wounds. 2004;16(6) 

In This Article

Results

Controlled streaming of enzymes could be readily and conveniently applied as a series of consecutive treatments using a multichannel pump, as demonstrated in Figure 2A, for treatments of six anesthetized rats or treatment of six different sites on a larger animal (Figure 2B). Effective digestion of different skin layers was readily achieved by streaming diluted buffered enzyme solutions for three hours. The controlled streaming of 2mg/mL papain onto mice effected digestion and removal of the outer keratinized layer (compare Figure 3A to Figure 3B). Detachment of the epidermis from the dermis was effected by a trypsin (4mg/mL) and bromelain (5mg/mL) mixture (Figure 3C). Controlled streaming of 8mg/mL trypsin solution effected complete digestion of the epidermis layer (Figure 3D). Streaming of 3mg/mL pepsin resulted in deeper penetration and collagen fiber digestion (Figure 3E). Streaming of a mixture of 3mg/mL collagenase and 1.5mg/mL thermolysin resulted in digestion similar to that shown in Figure 3D.

This photograph demonstrates simultaneous six-channel streaming of enzymes.

Pictured here are histological sections of mouse skin treated with streaming of proteases for three hours: (A) untreated; (B) papain treated (right side); (C) trypsin—bromelain mixture; (D) trypsin (left side); (E) pepsin.

Pictured here are histological sections of mouse skin treated with streaming of proteases for three hours: (A) untreated; (B) papain treated (right side); (C) trypsin—bromelain mixture; (D) trypsin (left side); (E) pepsin.

Pictured here are histological sections of mouse skin treated with streaming of proteases for three hours: (A) untreated; (B) papain treated (right side); (C) trypsin—bromelain mixture; (D) trypsin (left side); (E) pepsin.

Pictured here are histological sections of mouse skin treated with streaming of proteases for three hours: (A) untreated; (B) papain treated (right side); (C) trypsin—bromelain mixture; (D) trypsin (left side); (E) pepsin.

Pictured here are histological sections of mouse skin treated with streaming of proteases for three hours: (A) untreated; (B) papain treated (right side); (C) trypsin—bromelain mixture; (D) trypsin (left side); (E) pepsin.

Similar results were obtained by streaming of same solutions on rat, rabbit, and pig skins (data not shown).

Streaming of active enzyme solutions was essential to obtain these effects. Streaming of buffer solution without enzymes was ineffective. Furthermore, streaming of enzyme solution for a few minutes to fill the system followed by flow arrest also resulted in no visual change.

The specific activity of all streamed enzyme solutions remained stable (>85%) throughout the three-hour application period. The minor loss of input activity was most probably caused by autodigestion.

Effective removal of fresh blood clots was readily achieved by streaming of trypsin and collagenase mixture (3mg/mL each) for three hours onto freshly made cuts with smooth surface cleaning regardless of their shape (compare Figures 4A and C with Figures 4B and D).

These photographs demonstrate effectiveness of removal of coagulated blood by streaming of trypsin and collagenase mixture.

These photographs demonstrate effectiveness of removal of coagulated blood by streaming of trypsin and collagenase mixture.

These photographs demonstrate effectiveness of removal of coagulated blood by streaming of trypsin and collagenase mixture.

These photographs demonstrate effectiveness of removal of coagulated blood by streaming of trypsin and collagenase mixture.

Controlled enzymatic streaming for burn wound debridement was also readily achieved by two hours streaming of several protease combinations, including collagenase/thermolysin mixture (3mg/mL and 1.5mg/mL, respectively) (Figure 5B), trypsin/papain mixture (4mg/mL and 2mg/mL) (Figure 5C), and trypsin/collagenase mixture (3mg/mL each) (Figure 5D).

These photographs illustrate burn wound debridement by streamed proteases: (A) untreated; (B) collagenase/thermolysin treated; (C) trypsin/papain treated; (D) trypsin/collagenase treated.

Debridement with streamed enzymes, e.g., papain or pepsin (2mg/mL and 3mg/mL, respectively), for two hours resulted in smooth healing (compare Figure 6A with Figure 6B; photographs taken 20 days post-burn induction).

These photographs illustrate healing of burn wounds debrided by papain: A) untreated; (B) papain treated.

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