[A new composite matrix bridging both stumps of spinal cord transection in rats to promote recovery of motor function].

UNLABELLED: OBJECTIVE; To investigate a new composite matrix (BMSCs seeded on the denuded human amniotic membrane, BMSCs-DHAM) bridging the both stumps of spinal cord injury in rats to promote axon regeneration and improve motor function of hind limbs.

METHODS: The human amniotic membrane (HAM) was voluntarily donated by the healthy pregnant women after a caesarean section. The cells on the HAM were completely removed with a tryptic and mechanical approach to prepare DHAM. The BMSCs were separated and cultured from 4-week-old female rats (n = 4), then the forth passage of BMSCs were labeled by PKH26 and seeded on DHAM (BMSCs-DHAM). The growing state of BMSCs was observed under the microscopy. Moreover, 40 female rats (8-week-old, weighting 200-220 g) were made spinal cord injury models by transecting at T9 level, and were randomly divided into 4 groups (each group, n = 10). The both stumps were respectively wrapped by BMSCs-DHAM or simple DHAM in groups A and C, and the same dose of BMSCs or physiological saline were also respectively injected the central lesion in groups B and D. At 12 weeks after surgery, the functional recovery of the hindlimbs was evaluated by the BBB locomotor rating score, and other indexes were tested including cortical motion evoked potential (MEP), anterograde biotinylated dextran amine (BDA) tracing, and immunofluorescence of neurofilament protein 200 (NF-200).

RESULTS: HE staining proved that the DHAM was devoid of cellular components by this way, and BMSCs grew well on the substrate under the microscopy. At 12 weeks after operation, the BBB score (12.50 +/- 1.26) in group A was significantly higher than those of other groups (P < 0.05), and the recovery in latency (3.52 +/- 2.45) ms and amplitude (480.68 +/- 18.41) microV of MEP was also obviously improved in group A (P < 0.05) when compared with other groups. In addition, anterograde BDA tracing revealed that the rate of the positive BDA axons 54.12% +/- 3.30% under the lesion level in group A was higher than those of other groups (P < 0.05), and lots of the regeneration axons (positive NF-200) were found to grow into the spinal cord under the composite matrix in group A.

CONCLUSION: The BMSCs-DHAM composite matrix can improve hindlimb motor function to some extent after spinal cord injury. It will be widely applied as the matrix material in the future.