Protective Effect Of Calcitriol On Spinal Motor Neuron After Peripheral Nerve Injury

Objective:To investigate the protective effect of calcitriol on spinal cord anterior horn motor neurons.Methods:48 SD rats (250-300g body weight) were divided into 2 groups, control group and calcitriol intervention group. 24 rats each group. The right sciatic nerve was cut off, with proximal ligation and the distal ends were embedded into biceps femoris. After surgery, animals in the intervention group were treated with calcitriol 2μg·kg-1·d-1, animals in the control group were treated with equivalent fat milk. The treatment was lasted for 7 days. Animals were killed at 1 week, 2 weeks and 4 weeks. The specimen of L4～L6 spinal cord was taken and sectioned. The Nissel, the cholinesterase (CHE) and acid phosphatase (ACP) in motor neurons were stained and analyzed.Results:At the same point, compaired with the control group, the number of neurons in spinal cord anterior horn in calcitriol group were higher in calcitriol intervention group than in control group[1 week:(90.83±3.52)%vs. (84.31±6.52)%, P<0.01;2 weeks:(84.14±2.30)%vs.(76.30±2.74)%, P<0.01;4 weeks:(76.15±2.72) %vs. (73.40±1.91)%, P<0.05];the CHE activity was significantly higher in calcitriol intervention group than in control group[1 week:(69.11±1.38)% vs. (59.48±1.03)% P<0.01;2 weeks(74.45±3.39)%vs.(65.79±3.97)%, P<0.01;4 weeks:(78.86±6.58)%, P<0.01]; and ACP activity was significantly lower in calcitriol intervention group than in control group[1 week:(182.78±5.51)% vs.(206.53±14.71)%, P<0.01;2 weeks: (115.04±12.53)%vs. (138.21±9.85)%, P<0.01;].Conclusion:1. After peripheral nerve injury, spinal cord motor neuron degeneration occurs, the number of spinal cord anterior horn motor neurons reduced, levels of cholinesterase and acid phosphatase increased; 2. Calcitriol can reduce the peripheral nerve injury-induced spinal motor neuron death, alleviate the reduction of the cholinesterase (CHE) within motor neurons, and reduce the increase of the acid phosphatase (ACP) levels within motor neurons after the peripheral nerve injury; 3. Calcitriol have neuroprotection effects on motor neurons in anterior horn of the spinal cord.