Neuroprotective effect of the peroxisome proliferator-activated receptor γ agonist lobeglitazone following intracerebral hemorrhage in rats.

Abstract

Lobeglitazone, an oral antidiabetic medication, acts as a peroxisome proliferator-activated receptor γ (PPARγ) agonist and demonstrates neuroprotective effects. This study investigated beneficial effects and mechanisms of lobeglitazone treatment in an experimental intracerebral hemorrhage (ICH) rat model. ICH was induced in the left striatum of Sprague-Dawley rats by administration of 0.6 units of collagenase type IV. Rats with ICH were assigned randomly to three treatment groups: (1) control group, (2) lobeglitazone 2 mg/kg, and (3) lobeglitazone 4 mg/kg (N = 6, in each group). Medications were administered orally for 3 days following ICH. Outcomes were measured based on brain edema on the third day after ICH. Behavioral outcomes were evaluated on days 1, 3, 6, and 13 following ICH utilizing the modified neurological severity score (mNSS). On the third day after ICH, inflammatory cytokines were evaluated using western blotting, and inflammatory cells were examined through immunohistochemistry. Administration of lobeglitazone at a dosage of 4 mg/kg reduced brain edema significantly (15 %) in comparison to the control and 2 mg/kg (7 %) groups. Moreover, lobeglitazone administration at a dosage of 4 mg/kg suppressed infiltration of macrophages and neutrophils in perihematomal areas. Expression of several inflammatory cytokines, including interleukin-1 beta (IL-1b), extracellular signal-regulated kinase (ERK), and cyclooxygenase-2 (COX2) were also reduced. Regarding functional outcomes, a high dose of lobeglitazone (4 mg/kg) improved the mNSS significantly on days 3 and 13 after ICH. The results suggest that lobeglitazone, a PPARγ agonist, has potential neuroprotective effects on ICH by modulating brain edema and brain inflammation via IL-1β-ERK-COX-2 pathway inhibition.