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IGF‐I response to tourniquet‐induced injury in young and old mice
Author(s) -
Hammers David,
Merritt Ed,
Walters Tom,
Baer Dave,
Matheny Wayne,
Adamo Martin,
Farrar Roger
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a1304
Subject(s) - medicine , adult male , tourniquet , young adult , skeletal muscle , endocrinology , ischemia , insulin like growth factor , growth factor , physiology , anesthesia , receptor
The age‐associated decline in skeletal muscle’s ability to regenerate is a concern among elderly patients of limb injury or orthopedic surgery. Changes in insulin‐like growth factor‐I (IGF‐I) response have been implicated in this phenomenon. Previously, our laboratory has shown a drastic increase in IGF‐I mRNA 7 days following tourniquet (TK) induced damage in adult rats, a response not seen in elderly rats. This study investigated the short‐term time course of IGF‐I expression in adult (6 month‐old) and elderly (24 month‐old) mice following 1, 3, 5, and 7‐day recovery from 2 hour TK induced ischemia/reperfusion injury. RT‐PCR analysis reveals an increase in IGF‐I expression in both TK groups. Levels peaked ~20‐fold 3 days post‐injury in adult and ~8‐fold 5 days post‐injury in elderly subjects. Adult expression decreased sharply at day 5 and rose by day 7, suggesting the differential, temporal‐specific expression of the IGF‐I Ea and Eb isoforms in injury repair described by Goldspink et al . The early IGF‐I response seen in adult subjects was not present in elderly subjects.