Abnormal connexin expression underlies delayed wound healing in diabetic skin.
OBJECTIVE
Dynamically regulated expression of the gap junction protein connexin (Cx)43 plays pivotal roles in wound healing. Cx43 is normally downregulated and Cx26 upregulated in keratinocytes at the edge of the wound as they adopt a migratory phenotype. We have examined the dynamics of Cx expression during wound healing in diabetic rats, which is known to be slow.


METHODS
We induced diabetes with streptozotocin and examined Cx expression and communication in intact and healing skin.


RESULTS
We found that diabetes decreased Cx43 and Cx26 protein and communication in the intact epidermis and increased Cx43 protein and communication in the intact dermis. Diabetes also altered the dynamic changes of Cxs associated with wound healing. Within 24 h, Cx43 was upregulated in a thickened bulb of keratinocytes at the wound edge (rather than downregulated as in controls, which formed a thin process of migratory cells). Cx43 decline was delayed until 48 h, when reepithelialization began. Although Cx26 was upregulated as normal after wounding in diabetic skin, its distribution at the wound edge was abnormal, being more widespread. Application of Cx43-specific antisense gel to diabetic wounds prevented the abnormal upregulation of Cx43 and doubled the rate of reepithelialization, which exceeded control levels.


CONCLUSIONS
Cx expression in diabetic skin is abnormal, as is the dynamic response of Cx43 to injury, which may underlie the delayed healing of diabetic wounds. Preventing the upregulation of Cx43 in diabetic wounds significantly improves the rate of healing and clearly has potential therapeutic value.
Wang
Chiuhui Mary
CM
Department of Anatomy and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
Lincoln
Jill
J
Cook
Jeremy E
JE
Becker
David L
DL
D000818:Animals; D000072259:Connexin 26; D018031:Connexin 43 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D017630:Connexins / Q000502:physiology; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D005786:Gene Expression Regulation; D015603:Keratinocytes / Q000502:physiology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000503:physiopathology*; D014945:Wound Healing / Q000502:physiology*; D014947:Wounds and Injuries / Q000235:genetics / Q000503:physiopathology*
D018031:Connexin 43; D017630:Connexins; C000607044:Gjb2 protein, rat; D000072259:Connexin 26