Rh-CSF1 Attenuates Oxidative Stress and Neuronal Apoptosis via the CSF1RPLCG2PKAUCP2 Signaling Pathway in a Rat Model of Neonatal HIE

Abstract EN

Oxidative stress (OS) and neuronal apoptosis are major pathological processes after hypoxic-ischemic encephalopathy (HIE).

Colony stimulating factor 1 (CSF1), binding to CSF1 receptor (CSF1R), has been shown to reduce neuronal loss after hypoxic-ischemia- (HI-) induced brain injury.

In the present study, we hypothesized that CSF1 could alleviate OS-induced neuronal degeneration and apoptosis through the CSF1R/PLCG2/PKA/UCP2 signaling pathway in a rat model of HI.

A total of 127 ten-day old Sprague Dawley rat pups were used.

HI was induced by right common carotid artery ligation with subsequent exposure to hypoxia for 2.5 h.

Exogenous recombinant human CSF1 (rh-CSF1) was administered intranasally at 1 h and 24 h after HI.

The CSF1R inhibitor, BLZ945, or phospholipase C-gamma 2 (PLCG2) inhibitor, U73122, was injected intraperitoneally at 1 h before HI induction.

Brain infarct volume measurement, cliff avoidance test, righting reflex test, double immunofluorescence staining, western blot assessment, 8-OHdG and MitoSOX staining, Fluoro-Jade C staining, and TUNEL staining were used.

Our results indicated that the expressions of endogenous CSF1, CSF1R, p-CSF1R, p-PLCG2, p-PKA, and uncoupling protein2 (UCP2) were increased after HI.

CSF1 and CSF1R were expressed in neurons and astrocytes.

Rh-CSF1 treatment significantly attenuated neurological deficits, infarct volume, OS, neuronal apoptosis, and degeneration at 48 h after HI.

Moreover, activation of CSF1R by rh-CSF1 significantly increased the brain tissue expressions of p-PLCG2, p-PKA, UCP2, and Bcl2/Bax ratio, but reduced the expression of cleaved caspase-3.

The neuroprotective effects of rh-CSF1 were abolished by BLZ945 or U73122.

These results suggested that rh-CSF1 treatment attenuated OS-induced neuronal degeneration and apoptosis after HI, at least in part, through the CSF1R/PLCG2/PKA/UCP2 signaling pathway.

Rh-CSF1 may serve as therapeutic strategy against brain damage in patients with HIE.