文本框: PLASMA IGF-1 AND IGFBP-3 LEVELS IN NEWBORN PIGLETS WITH HYPOXIC-ISCHEMIC BRAIN DAMAGE
WANG Q, YAO Y-J, LI W-R
Department of Pediatrics, Second University Hospital, West China Medical Center, Sichuan University, Chengdu, China

Objectives: The insulin-like growth factor 1(IGF-1) is involved in fetal brain development. There are marked changes in the IGF system in the brain in reponse to asphyxia with an induction of IGF-1 and insulin-like growth factor binding protein (IGFBP)-2 and IGFBP-3 in the region of injury. This Study was to analyse the plasma levels of IGF-1 and IGFBP-3 in newborn piglets at early stage of hypoxic-ischemic brain damage (HIBD).
Methods: Anaethetised 3-day-old piglets (n=37,BW 0.5-1.0kg) were induced by ligation of left carotid artery (ischemia) and followed by exposure to 8% oxygen and 92% nitrogen in an airtight box for 2 h (hypoxia), and then back to normal room air. Blood samples were taken from 31 HIBD piglets at 1,24,48 and 72 h after the induction and from 6 control piglets immediately after sham operation. Plasma IGF-1 and IGFBP-3 levels were measured with immuno-radiometric assay.
Results: Plasma concentrations of IGF-1 and IGFBP-3 at 72 h after HIBD (34.31±1.91, 1118.17±68.20 ng/ml) were strikingly lower than those in control (39.51±4.96, 1312.83±164.97 ng/ml, P<0.05). Plasma IGF-1 levels at 72h after HIBD were statistically lower than those at 1,24 and 48 h after HIBD (39.14±2.32, 38.29±4.55, 38.28±3.67 ng/ml, P<0.05). Plasma IGFBP-3 levels at 72h after HIBD were significantly lower than those at 48 h after HIBD (1301.75±138.41ng/ml, P < 0.05).
Conclusion: IGF-1 and IGFBP-3 plasma levels are decreased at 72 h after HIBD. It’s correlated to the severity of HIBD. At early stage of HIBD, increased demand for growth factors, shift of IGF-1 “pool” from peripheral blood to brain, inappropriate induction of neuronal apoptosis occurred for at least 72 h or central inhibition of the somatotrophic axis may contributed to these low plasma concentrations. Growth factors such as IGF-1 and IGFBP-3 may play an important role in the pathophysiology of HIBD, and IGF-1 may have a considerable effect on future therapeutic regimens.


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