Dynamic changes in insulin-like growth factor I immunoreactivity correlate to repair events in rat ear after freeze-thaw injury.
The distribution of the trophic peptide insulin-like growth factor I (IGF-I) in the rat ear was mapped after freeze-thaw injury. Immunocytochemical methods and antisera specific to human IGF-I were used. In the ear of normal adult rats scattered basal epidermal cells and a few cells in the underlying connective tissue and elastic cartilage expressed IGF-I immunoreactivity. Within 1 day after injury and reaching maximum in 3 days, all epidermal cells became stained as did invading macrophages and some of the other inflammatory cells. Concomitantly, there were hypertrophic changes. The staining leveled off after 1-2 weeks. Perichondrial cells became IGF-I immunoreactive in increasing frequency during the first week, reached maximal intensity and frequency in 2 weeks, and remained stained for at least 4 weeks. New cartilage was formed concomitantly on both sides of the old one. It is proposed that IGF-I is a substance of general importance for cell maintenance and tissue repair.
D000818:Animals; D004425:Ear Cartilage / Q000378:metabolism / Q000473:pathology; D004431:Ear, External / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D004487:Edema / Q000378:metabolism; D004817:Epidermis / Q000378:metabolism / Q000473:pathology; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D005260:Female; D005615:Freezing; D007150:Immunohistochemistry; D007249:Inflammation / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013002:Somatomedins / Q000378:metabolism*; D014945:Wound Healing
D013002:Somatomedins; D007334:Insulin-Like Growth Factor I