ABSTRACT
Diabetic peripheral neuropathy (DPN) is a common microvascular complication of diabetes associated with high disability rate and low quality of life. Tang-Luo-Ning (TLN) is an effective traditional Chinese medicine for the treatment of DPN. To illustrate the underlying neural protection mechanisms of TLN, the effect of TLN on electrophysiology and sciatic nerve morphology was investigated in a model of streptozotocin-induced DPN, as well as the underlying mechanism. Sciatic motor nerve conduction velocity and digital sensory nerve conduction velocity were reduced in DPN and were significantly improved by TLN or α -lipoic acid at 10 and 20 weeks after streptozotocin injection. It was demonstrated that TLN intervention for 20 weeks significantly alleviated pathological injury as well as increased the phosphorylation of ErbB2, Erk, Bad (Ser112), and the mRNA expression of neuregulin 1 (Nrg1), GRB2-associated binding protein 1 (Gab1), and mammalian target of rapamycin (Mtor) in injured sciatic nerve. These novel therapeutic properties of TLN to promote Schwann cell survival may offer a promising alternative medicine for the patients to delay the progression of DPN. The underlying mechanism may be that TLN exerts neural protection effect after sciatic nerve injury through Nrg1/ErbB2âErk/Bad Schwann cell survival signaling pathway.
ABSTRACT
OBJECTIVE: To study the effects of Qiwei Granule (QWG) on the protein and mRNA expressions of renal tissue transforming growth factor beta1 (TGF-beta1) in KK-Ay mice with spontaneous type 2 diabetes mellitus (T2DM). METHODS: Spontaneous T2DM KK-Ay mice model was adopted. Forty-five male mice were randomly divided into three groups, i. e., the model group, the Chinese medicine group, and the Western medicine group, 15 in each group. Fifteen male C57BL/6J mice were set up as the normal control group. The mice in the Chinese medicine group and the Western medicine group were administered intragastrically with QWG (at the daily dose of 20 g/kg) and valsartan (at the daily dose of 10 mg/kg), and the treatment lasted for 12 successive weeks. The pathological changes of the kidney were observed using HE staining, PAS, and Masson staining. The protein and mRNA expressions of TGF-beta1, were detected using immunohistochemical method and Real-time fluorescent quantitative PCR. RESULTS: The renal pathological changes of mice in the model group showed hypertrophic glomeruli, widened mesenteric matrix, increased mesangial cells, vacuolar renal tubular epithelial cells, tubular ectasia, and foci atrophy. Necrosis was occasionally seen. More protein cast, mesenchymal infiltration of inflammatory cells, and interstitial fibrosis could be seen. The protein and mRNA expressions of TGF-beta1 increased more in the model group than in the normal control group. After treatment by QWG and valsartan, the renal pathological changes were obviously alleviated, and the protein and mRNA expressions of TGF-beta1 were obviously lowered (P<0.05). CONCLUSION: By inhibiting the protein and mRNA expressions of TGF-beta1, QWG could play a role in preventing and curing diabetic nephropathy.
