Neutrophil depletion in the early inflammatory phase delayed cutaneous wound healing in older rats: improvements due to the use of un-denatured camel whey protein

BACKGROUND: While it is known that advanced age alters the recruitment of neutrophils during wound healing, thereby delaying the wound healing process, little is known about prolonged wound healing in advanced ages. Thus, we investigated the correlation of neutrophil recruitment with healing events, and the impact of whey protein (WP) on neutrophil activation. METHODS: The animals were allocated into wounded young group, wounded older group and wounded older rats with daily treatment of WP at a dose of 100 mg/kg of body weight. RESULTS: Our results pointed to a marked deficiency in the number of neutrophils in the wounds of older rats, which was accompanied with impairment of the healing process. In the group of older rats, phagocytic activity, as tested by fluorescence microscopy, declined throughout the first 24 hours after wounding. Both the neutrophil number and the phagocytic activity recovered in older rats which received WP supplementation. Interestingly, WP was found to significantly up-regulate the MIP-1α and CINC-1 mRNA expression in old rats. On the other hand, the wound size in older rats was significantly higher than that in younger ones. Blood angiogenesis was also significantly delayed in the older group as opposed to the young rats. WP, however, was found to return these indices to normal levels in the older rats. Proliferation and epidermal migration of the keratinocytes and the collagen deposition were also returned to the normal rates. CONCLUSIONS: This data confirms the critical role of neutrophil recruitment in the early inflammatory phase of wound healing in older rats. In addition, WP protein was used to improve neutrophil function in older rats, healing events returned to a more normal profile. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2100966986117779.