脊髓神经元PTEN蛋白在大鼠糖尿病神经痛中的作用

Role of PTEN protein in spinal cord neurons in diabetic neuropathic pain in rats

目的探讨脊髓神经元第10号染色体同源缺失性磷酸酶张力蛋白基因（PTEN）蛋白在大鼠糖尿病神经痛中的作用。方法雄性SD大鼠，2月龄，体重180～200g，采用腹腔注射1％链脲佐菌素（STZ）60mg／kg的方法制备糖尿病模型。取糖尿病神经痛大鼠16只，采用随机数字表法，将其分为2组（n=8）：糖尿病神经痛组（DNP组）和糖尿病神经痛＋PTEN蛋白抑制剂bpv组（DPN-bpv组）；另取16只大鼠，采用随机数字表法，将其分为2组（n=8）：对照组（C组）和bpv组。DNP-bpv和bpv组于注射STZ后14—28d时腹腔注射bpv0．2mg／kg，1次／d。分别于注射STZ前（T．）、注射STZ后2、7、14、21、28d（T2-6）时测定机械缩足反应阈（MWT），测定MWT后处死大鼠，取L4,5脊髓组织，采用ELISA法检测PTEN蛋白活性，采用Western blot法检测丝氨酸，苏氨酸蛋白激酶（Akt）（s473）磷酸化水平。结果与C组比较，DNP组和DNP—bpv组T4-6时MWT降低，脊髓PTEN蛋白活性和Akt（s473）磷酸化水平升高（P〈0．05或0．01）；与DNP组比较，DNP—bpv组T。时MWT升高，脊髓PTEN蛋白活性和Akt（s473）磷酸化水平降低（P〈0．05）。结论脊髓神经元PTEN蛋白参与了大鼠糖尿病神经痛的维持。

Objective To investigate the role of phosphatase and tcnsin homologue deleted on chromosome 10 （PTEN） protein in the spinal cord neurons in diabetic neuropathic pain （DNP） in rats. Methods Male Sprague-Dawley rats, aged 2 months, weighing 180-200 g, were studied. Diabetes mellitus was induced by single intraperitoneal injection of streptozotocin （STZ） 60 mg/kg. Sixteen rats with DNP were randomly divided into 2 groups （n = 8 each） using a random number table： DNP group and DNP＋PTEN inhibitor bpv （pie） group （DPN-bpv group）. Another 16 rats were equally and randomly divided into either control group （group C） or bpv group. In DNP-bpv and bpv groups, bpv （pic） 0.2 mg/kg was injected intraperitoneally once a day within 14-28 days after injection of STZ. Before STZ injection （T1）, and at 2, 7, 14, 21 and 28 days after STZ injection （T2.6 ）, the mechanical paw withdrawal threshold （MWT） was measured. After measurement of MWT, the rats were sacrificed, and the lumbar segments of the spinal cord （ L4.5 ） were removed for determination of PTEN protein activity （ by ELISA） and Akt （s473） phosphorylation （by Western blot）. Results Compared with group C, the MWT was significantly decreased at T4.6 , and the PTEN protein activity and Akt （s473） phosphorylation were significantly increased in DNP and DNP-bpv groups （P〈0.05 or 0.01 ）. Compared with group DNP, the MWT was significantly increased at T6 , and the PTEN protein activity and Akt （s473） phosphorylation were significantly decreased in group DNP-bpv （P〈0.05）. Conclusion PTEN protein in the spinal cord neurons is involved in the maintenance of DNP in rats.