miR-21 inhibits apoptosis of Schwann cells following peripheral nerve injury

AIM: To explore the relationship and molecular mechanism between microRNA-21(miR-21) and Schwann cells (SC) following peripheral nerve injury. METHODS: The mRNA expression of miR-21 and phosphatase and tensin homologue deleted on chromosome ten (PTEN) in animal model were detected by real-time PCR. The over-expression of miR-21 and inhibition of miR-21 expression in the Schwann cells according to transfection of lentiviral vectors were performed, the nonspecific miRNA was used as a negative control (NC). The cell apoptosis was measured by flow cytometry. The mRNA expression of miR-21 and PTEN in the cells was detected by real-time PCR. The protein expression of PTEN and cleaved caspase-3 was determined by Western blot. RESULTS: The level of miR-21 was significantly higher and the mRNA level of PTEN was significantly lower in the model of nerve injury than those in control group. miR-21 over-expression decreased the number of apoptotic Schwann cells compared with NC-SC. The mRNA expression of PTEN was down-regulated by over-expression of miR-21. The protein expression of PTEN and cleaved caspase-3 was down-regulated by over-expression of miR-21(P<0.05). CONCLUSION: miR-21 may play an important role in the peripheral nerve injury through inhibiting apoptosis of Schwann cells by down-regulating the expression of PTEN.