Introduction

A wound is a disruption in the normal anatomical structure and function of living tissue that can be caused by physical, chemical, microbiological or immunological injury. Wound healing is essentially a survival mechanism and represents an attempt to maintain normal anatomical structure and function. When healing takes place in a direction away from its normal course, it may result in non-healing, under-healing or over healing. Therefore attempts have been made to accelerate wound healing either when it is progressing normally₁ or when it is suppressed by corticosteroids₂, anti-neoplastic₃ and non-steroidal anti-inflammatory agents₄. Treatment is aimed at either shortening the time required for healing or minimizing the undesired consequences.

A large section of world population relies on traditional remedies to treat a plethora of diseases. Medicinal herbs are an indispensable part of traditional medicine practiced all over the world due to low cost, easy access and ancestral experience. The greatest contribution of plant kingdom to mankind is that it has provided a large variety of potent drugs to alleviate suffering from disease. The plant Michelia champaca (Sampige), used in this study is widely used in both Ayurveda and Homeopathic medicine. It belongs to the family Magnoliaceae. Root and bark are purgative, emmenagogue and are useful in the treatment of inflammation, constipation and dysmennorhea. The stem bark is astringent, febrifuge used in gastritis, fever and cough. Flower and flower buds, fruits are useful in ulcers, skin disease wounds₆. A survey of literature revealed that the wound healing activity of Michelia champaca, has not been evaluated. So, it was decided to determine the wound healing activity of this plant and to study its effects on Dexamethasone suppressed wound healing in various animal models in Wistar rats.

Materials and Methods

Ethical clearance: Institutional Animal Ethics Committee cleared all the protocol of the study.

Animals

Study design

Dosing schedule

Wound Model

Statistical analysis

Results

Incision wound model: The mean breaking strength in the Group 1 was 204.58±8.04g and it was increased to 236.66±16.10g in the Group 2. In Group 3, the breaking strength was significantly reduced to 164.58±9.16g as compared to Group 1, and significantly (p<0.028) increased in Group 4 (217.08±9.1g) compared to Group1 and Group 3 [ Table 1 ].

Excision wound model: The percentage of wound contraction in the group 1 was 25.46±5.3, 51.16±0.58, 92.20±1.24 and 98.06±0.39 as measured on the 4th, 8th, 12th 16th day respectively. The wound contraction rate was not significantly altered in groups 2 & 4 as compared to group 1. The mean period of epithelization in the group 1 was 21.00±0.68 days. The rate of wound contraction was not significantly altered in animals treated with both Dexamethasone and M. champaca [Table 2].

Dead space wound model: The mean breaking strength of the granulation tissue in the group 1 was 230.83±21.11g. An increase in the breaking strength of granulation tissue was observed in the M.champaca treated group. The breaking strength of Dexamethasone treated group was significantly reduced to 155±6.05g as compared to group 1.

There was increase in breaking strength of granulation tissue in group 4 when compared to group 3 (table-3)

The mean dry weight of granulation tissue in the group 1 was 0.060±0.012mg. This was increased to 0.065±0.061mg in the group 2. The mean dry weight of granulation tissue in group 3 was 0.070±0.015mg (statistically significant) (table 3)

The mean hydroxyproline content of granulation tissue of the group 1 was 926.6±239.6mg/g of the tissue. It was significantly altered in group 4 (p<0.000) [Table 3]

Figure 1

Table 1 :Effect of drugs on Incision wound parameters

Figure 2

Table 2:Effect of drugs on Excision wound parameters

Figure 3

Table 3: Effect of Drugs on dead space wound parameters

Discussion

In the present study, the breaking strength of the incision wound was not significantly increased in the M.champaca treated group as compared to control. In the dead space wound model also, there was no marked increase in breaking strength of granulation tissue in the test group. The hydroxyproline content and dry weight of granulation tissue were however, not altered significantly. Thus it could be that M.champaca might not have increased the collagen content, but probably altered the maturation process, by affecting cross linking of collagen.

Dexamethasone inhibits wound contraction, granulation tissue and collagen formation₂. This is the cause of suppressed wound healing in the Dexamethasone treated group in all wound models. The effect of Dexamethasone was reversed by M.champaca in incision and dead space wound models, where the breaking strength of Dexamethasone + M.champaca treated was not significantly higher than that of the group treated with Dexamethasone alone. Hydroxyproline content of Dexamethasone + M.champaca was significantly higher than group treated with Dexamethasone alone.

Oxidative stress has been implicated in a variety of degenerative processes and diseases including wound healing₁₇. This could contribute to its pro-healing effects. M.champaca also reversed the suppression of wound healing by Dexamethasone.

The enhanced wound contraction effect and epithelization by M.champaca could possibly be made use clinically for healing wounds in immunocompromised patients and in patients on long term steroid therapy.