RESUMO
ObjectiveTo investigate the effect of modified Huangqi Guizhi Wuwutang （MHGW） on the protein and mRNA expression of B-cell lymphoma-2-associated X protein （Bax） and cysteinyl aspartate specific proteinase-12 （Caspase-12） related to the apoptosis of sciatic nerve cells in diabetes rats to explore the mechanism of MHGW in the treatment of peripheral neuropathy in diabetes. MethodAnimal experiments were conducted. A diabetes model was induced in sixty male sprague-dawley （SD） rats by feeding on a high-sugar and high-fat diet combined with streptozotocin （STZ） intraperitoneal injection. Rats with random blood glucose levels ≥ 16.7 mmol·L-1 for three consecutive days were considered to have successfully developed diabetes. Forty-eight rats that successfully developed diabetes were randomly divided into a model group， an α-lipoic acid group （0.026 8 g·kg-1·d-1）， a high-dose MHGW group （2.5 g·kg-1·d-1）， and a low-dose MHGW group （1.25 g·kg-1·d-1）， with 12 rats in each group. Another 10 rats were assigned to the normal group. Body weight and random blood glucose levels of the rats were monitored. At the end of a 16-week intervention period， the sciatic nerve conduction velocity of the rats was measured using the Key point electromyography collection system. The protein and mRNA expression of Bax and Caspase-12 in the sciatic nerve cells was detected by Western blot analysis and real-time quantitative polymerase chain reaction （Real-time PCR）， respectively. ResultCompared with the normal group， the model group showed a significant decrease in body weight （P<0.01） and a significant increase in random blood glucose levels （P<0.01）. After a 16-week intervention， compared with the model group， the high-dose MHGW group exhibited a significant increase in body weight （P<0.05）， while there were no statistically significant differences in body weight changes among the other treatment groups. Random blood glucose levels significantly decreased in all treatment groups （P<0.01）. After 16 weeks of intervention， compared with the normal group， the model group had significantly reduced motor and sensory nerve conduction velocities （P<0.01）. Compared with the model group， all treatment groups showed significant increases in motor and sensory nerve conduction velocities （P<0.05， P<0.01）. The expression of Bax and Caspase-12 proteins in the sciatic nerve cells was significantly elevated in the model group compared with that in the normal group （P<0.01）. In contrast， all treatment groups showed significant reductions in the expression of Bax and Caspase-12 proteins in the sciatic nerve cells as compared with that in the model group （P<0.01）. The expression of Bax and Caspase-12 mRNA in the sciatic nerve cells significantly increased in the model group compared with that in the normal group （P<0.01）. Compared with the model group， the α-lipoic acid group and the high-dose MHGW group showed significant reductions in the expression of Bax mRNA in the sciatic nerve cells （P<0.05， P<0.01）， while the low-dose MHGW group showed a decreasing trend in the expression of Bax mRNA. The expression of Caspase-12 mRNA in the sciatic nerve cells significantly decreased in all treatment groups （P<0.01）. ConclusionMHGW may improve and repair sciatic nerve damage in diabetes rats by inhibiting sciatic nerve cell apoptosis.
RESUMO
ObjectiveTo investigate the protective effect of modified Huangqi Guizhi Wuwutang （MHGW） on endoplasmic reticulum stress in the sciatic nerve of diabetes rats based on the pathways of inositol-requiring enzyme 1α （IRE1α） and CCAAT/enhancer-binding protein homologous protein （CHOP）. MethodSixty rats were fed on a high-sugar and high-fat diet for six weeks， followed by intraperitoneal injection of streptozotocin at a dose of 35 mg·kg-1. Random blood glucose levels were measured three days later and rats with a sustained blood glucose level ≥ 16.7 mmol·L-1 were included in study （n=48）. The rats were randomly divided into a model group， an α-lipoic acid group （0.026 8 g·kg-1·d-1）， a high-dose MHGW group （2.5 g·kg-1·d-1）， and a low-dose MHGW group （1.25 g·kg-1·d-1）. Another 10 rats were assigned to the normal group. The intervention lasted for 16 weeks. After 16 weeks， the sciatic nerve structure of the rats in each group was observed under light microscopy using Luxol fast blue （LFB） staining. Transmission electron microscopy was used to observe the ultrastructure of the sciatic nerve. Chemiluminescence method was employed to measure the serum reactive oxygen species （ROS） levels. Western blot and real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） were used to evaluate the expression of p-IRE1α protein， IRE1α mRNA， CHOP protein， and CHOP mRNA in the sciatic nerve of the rats. ResultCompared with the normal group， the model group showed elevated serum ROS levels （P<0.01）. In contrast， the serum ROS levels were significantly reduced in the treatment groups compared with those in the model group （P<0.01）. The sciatic nerve of the model group showed pathological changes compared with that in the normal group， while the treatment groups exhibited improvement in sciatic nerve pathology compared with the model group. The protein expression of p-IRE1α and CHOP in the sciatic nerve significantly increased in the model group as compared with that in the normal group （P<0.01）. However， the treatment groups showed a significant decrease in the protein expression of p-IRE1α and CHOP in the sciatic nerve compared with the model group （P<0.05， P<0.01）. Furthermore， compared with the normal group， the model group showed upregulated mRNA expression of IRE1α and CHOP in the sciatic nerve （P<0.01）， while the treatment groups exhibited a significant decrease in the mRNA expression of IRE1α and CHOP compared with the model group （P<0.01）. ConclusionMHGW can alleviate endoplasmic reticulum stress-induced cell apoptosis and improve the structure and function of the sciatic nerve in diabetes rats by inhibiting the expression of IRE1α/CHOP pathway-related proteins and mRNA， thereby preventing and treating peripheral neuropathy in diabetes.