Bone Marrow Mesenchymal Stem Cell Transplantation Increases GAP-43 Expression via ERK1/2 and PI3K/Akt Pathways in Intracerebral Hemorrhage

Background/Aims: Intracerebral hemorrhage (ICH) occurs in hypertensive patients and results in high rates of mortality and disability. This study determined whether bone marrow mesenchymal stem cell (BMSC) transplantation affects axonal regeneration and examined the underlying mechanisms after the administration of PD98059 (p-ERK1/2 inhibitor) or/ and LY294002 (PI3K inhibitor). The hypothesis that was intended to be tested was that BMSC transplantation regulates the expression of growth-associated protein-43 (GAP-43) via the ERK1/2 and PI3K/Akt signaling pathways. Methods: Seventy-five male rats (250–280 g) were subjected to intracerebral blood injection and then randomly received a vehicle, BMSCs, PD98059 or LY294002 treatment. Neurological deficits were evaluated prior to injury and at 1, 3 and 7 days post-injury. The expression of GAP-43, Akt, p-Akt, ERK1/2, and p-ERK1/2 proteins was measured by western blot analysis. Results: BMSC transplantation attenuated neurological deficits 3-7 days post-ICH. The expression of GAP-43 was increased 3 days following BMSC transplantation. However, this increase was inhibited by either PD98059 or LY294002 treatment. Treatment with both PD98059 and LY294002 was more effective than was treatment with an individual compound. Conclusion: BMSC transplantation could attenuate neurological deficits and activate axonal regeneration in this rat ICH model. The protective effects might be associated with increased GAP-43 expression by activating both the ERK1/2 and PI3K/Akt signaling pathways.