A study on some effects of the extracts of unripe paw-paw (Carica papaya linn) on wound healing in Wistar rats ( Rattus novegicus)

Abstract

Background: Wound healing is the process of repair that follows injury to the skin and soft tissues. Attempt at finding a perfect wound-healing agent has a long history. The emphasis was on finding an agent that is affordable, effective and with minimal side effects.

Aim: To confirm some effects of the medicinal properties of the extracts of unripe pawpaw as a wound healing agent and it's reported antimicrobial activities.

Methods: Twenty adult male Wistar rats of average weight 150-200 g were used for this study. They were split into two groups: Normal saline (controls) and paw-paw (Carica papaya linn) extract experimental groups. Ethical clearance was obtained from relevant institutions and departments for this study. Each animal was weighed and anaesthetized using combinations of ketamine (0.1ml/kg) and diazepam (0.1ml/kg). Each rat was shaved on the right dorso-lateral aspect of the thoracic wall and wiped with 70% methylated spirit soaked in gauze. A 2 cm by 2 cm square skin area was measured    and    excised,   and   wounds   were dressed with paw-paw extracts in experimental group and normal saline in control group.

Results: The results revealed significant wound contraction (P<0.05) on day 9 in the experimental group (mean 62.4±3.5 cm) compared to the control group (mean 56.6± 3.6 cm). Histology of granulation tissue on day 9 showed significant decrease (P<0.05) in the mean fibroblast count in the experimental group (300.0 ±8.6) relative to the control group (443. 4±6.7). The mean blood vessels count was also significantly lower (P<0.05) in the experimental group (32.4 ± 2.7) relative to the control group (77.9 ± 4.1). Granulation tissue histology showed more inflammatory cells in the control group relative to that of experimental group, which appeared adequate, but were not as dense as the control group.

Conclusion: It was concluded that the extracts of unripe paw-paw could accelerate wound healing process due to its ability to enhance wound contraction.

Key words: Wound healing, Carica papaya linn, Unripe paw-paw