BackgroundWound healing involves the integration of complex biological processes. Several studies examined numerous approaches to enhance wound healing and to minimize its related morbidity. Both chitosan and mesenchymal stem cells (MSCs) were used in treating skin wounds. The aim of the current work was to compare MSCs versus chitosan in wound healing, evaluate the most efficient route of administration of MSCs, either intradermal or systemic injection, and elicit the mechanisms inducing epidermal and dermal cell regeneration using histological, immunohistochemical and fluorescent techniques.Material and MethodsForty adult male Sprague Dawley albino rats were divided into four equal groups (ten rats in each group): control group (Group I); full thickness surgical skin wound model, Group II: Wound and chitosan gel. Group III: Wound treated with systemic injection of MSCs and Group IV: Wound treated with intradermal injection of MSCs. The healing ulcer was examined on day 3, 5, 10 and 15 for gross morphological evaluation and on day 10 and 15 for histological, immunohistochemical and fluorescent studies.ResultsChitosan was proved to promote wound healing more than the control group but none of their wound reached complete closure. Better and faster healing of wounds in MSCs treated groups were manifested more than the control or chitosan treated groups. It was found that the intradermal route of administration of stem cells enhanced the rate of healing of skin wounds better than the systemic administration to the extent that, by the end of the fifteenth day of the experiment, the wounds were completely healed in all rats of this group. Histologically, the wound areas of group IV were hardly demarcated from the adjacent normal skin and showed complete regeneration of the epidermis, dermis, hypodermis and underlying muscle fibers. Collagen fibers were arranged in many directions, with significant increase in their area percent, surrounding fully regenerated hair follicles and sebaceous glands in the dermis of the healed areas more than in other groups.ConclusionMSCs enhanced the healing process of wound closure more than chitosan gel treatment. Furthermore, MSCs injected intradermally, were more efficient in accelerating wound healing than any other mode of treatment.

Hypoxia, due to impaired cerebral blood flow, has hazardous effects on brain structure and function. To minimize as much as possible the neurological consequences from hypoxic-ischemic (HI) brain injury, neuro-protective strategies are urgently required. Vitamin E has been shown to have protective effects against cerebral ischemia, possibly due to its anti-oxidant effects. Thirty white mice, of both sexes, were obtained from the animal house at King Khalid University Hospital, King Saud University. They were divided into three groups; each included 10 animals: Group A was considered as a control one, animals of Group B were subjected to a permanent link to the carotid arteries on both sides and animals of Group C underwent permanent link to carotid arteries on both sides and concomitantly were given Vitamin E as an anti-oxidant. Animals of Group C were injected by Vitamin E (equivalent to 15 mg/day), into the peritoneal cavity as a single dose for a week and after the prescribed period the mice were sacrificed under deep anesthesia and their brains were extracted and prepared for an electron microscopic study of brain tissue. Specimens from animals of Group B showed a large number of neurons that had been deteriorated. Mitochondria were the most affected organelles. There were a large number of dark cells which probably resulted from shrunken nerve cells and exhibited opaque nuclei. The number of affected nerve cells was much lower in brain tissues from animals of the Group C which revealed absence of dark cells. The study did not disclose any similar changes in brain tissues of the control group animals. Our results suggested that treatment with Vitamin E after hypoxia-ischemia led to a neuro-protective effect that appeared in reduction of cell death of neurons. Thus, the present study provides an evidence that Vitamin E protects the brain tissue of the consequences of hypoxia caused by ischemia in the tested experimental animals. It could be recommended in the treatment of cerebrovascular stroke and neurodegenerative diseases.

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