OBJECTIVETo investigate the anti-apoptotic effect of low molecular weight heparin (LMWH) in the placenta of rats with preeclampsia-like symptoms.

METHODSThirty pregnant Wistar rats were randomized equally into 3 groups and received subcutaneous saline injection (control group), 200 mg/kg L-NAME injection to induce preeclampsia symptoms (PE group), or L-NAME with 40 µl/kg LMWH injections (LMWH group). The blood pressure, urine protein, the number of pups and the weight of the fetuses and placenta were measured, and the placental apoptotic index was measured by TUNEL assay. The expression of cleaved caspase-3, Bcl-2 and Bax in the placenta were examined by Western blotting.

RESULTSCompared with the control group, L-NAME injections caused significantly increased blood pressure and urine protein (P<0.05), which were significantly lowered by LWMH (P<0.05). The number and weight of normal pups were significantly lower in PE group than in the control group (P<0.05) and LMWH group (P<0.05); in LMWH group, the weight of pups was still lower than that of the control group (P<0.05) but the number of normal pups was comparable (P>0.05). The LMWH group showed a significantly lower placental apoptosis index than the PE group (P<0.05) with also significantly lower cleaved caspase-3 and Bax and higher Bcl-2 expressions (P<0.05). The apoptosis index and expressions of cleaved caspase-3, Bcl-2 and Bax protein were similar between LMWH group and normal pregnant group (P>0.05).

CONCLUSIONLMWH can alleviate preeclampsia-like symptoms and decrease the apoptosis in the placenta of rats possibly by enhancing Bcl-2 and suppressing Bax expressions.