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Objective: To investigate the molecular mechanism of oxaliplatin-induced chemotherapy-induced peripheral neuropathic pain (CIPNP). Methods: A total of 16 male Sprague-Dawley rats of specific pathogen-free grade were randomly divided into two groups: oxaliplatin experimental group (2.4 mg/kg oxaliplatin dissolved in 5.0% glucose solution, n =8) and control group (equal volume 5% glucose solution, n =8). The rat model of CIPNP was established by continuous administration with oxaliplatin. In addition, mechanical allodynia, thermal hyperalgesia and cold hyperalgesia were measured and compared between the two groups. To explore the molecular mechanism of oxaliplatin-induced CIPNP, the gene expression of dorsal root ganglia (DRG) from the rat model of CIPNP was analyzed using RNA sequencing (RNA-Seq). Results: Mechanical and thermal hypersensitivity was exhibited on day 7 and a stronger hypersensitivity was observed on day 14. A total of 20 152 genes were quantified by RNA-Seq, and 379 differentially expressed genes (DEGs) were obtained with absolute fold change cut-offs ≥ 2 and P value<0.05. There were 7 genes (Npy, Car3, Cdkn1a, Nts, Prc1, Ms4a7 and Ecel1) that were involved in peripheral nerve injury-related neuropathic pain. Gene ontology (GO) functional enrichment analyses indicated that the DEGs induced by oxaliplatin were involved in oxygen transport, cell division, intermediate, centromere, oxygen transporter activity, oxygen binding. Moreover, the result of Kyoto Encyclopedia of genes and genomes (KEGG) analyses highlighted that the DEGs induced by oxaliplatin were involved in malaria, African trypanosomiasis, primary immunodeficiency, peroxisome proliferator activated receptor (PPAR) signaling pathway. Conclusion: Oxaliplatin induces CIPNP via pain-related genes and signaling pathways.

Objective: To explore the effect of early insulin therapy on sterol regulatory element binding protein 1 (SREBP1) pathway and lipid accumulation in liver of type 2 diabetic rats (DM)., Methods: A high-fat diet plus a low-dose of streptozotocin (STZ) was administered to the Sprague-Dawley (SD) rats to create a type 2 diabetic animal model. Then the rats were divided into 3 groups: normal control (NC), DM (untreated diabetic rats) and INS (a 3-week treatment of NPH insulin initiated from day 3 of STZ injection). Insulin was delivered daily by a 3-week subcutaneous injection (6 - 8 U/day). Liver homogenate was prepared. The protein levels of ER stress marker immunoglobulin binding protein (Bip), oxygen-regulated protein 150 (ORP150), insulin-induced gene 1 (Insig1), SREBP1 and nuclear SREBP1 (nSREBP1) were assayed by Western blot. Adipose tissue mass was measured., Results: In the DM group, ER (endoplasmic reticulum) stress marker Bip and ORP150 were up-regulated (0.67 ± 0.02 vs 0.43 ± 0.01 for Bip; 1.11 ± 0.04 vs 1.83 ± 0.03 for ORP150, P < 0.05 for both) and Insig1 decreased (0.25 ± 0.02 vs 0.80 ± 0.07, P < 0.05). And the expressions of SREBP1 and nSREBP1 were elevated (1.03 ± 0.14 vs 0.41 ± 0.01 for SREBP1; 3.63 ± 0.77 vs 0.96 ± 0.20 for nSREBP1, P < 0.05 for both) in comparison with the normal control rats. In the INS group, all aforementioned changes became attenuated or reversed (0.41 ± 0.04 vs 0.67 ± 0.02 for Bip; 1.83 ± 0.03 vs 1.11 ± 0.04 for ORP150; 0.43 ± 0.02 vs 0.25 ± 0.02 for Insig1; 0.46 ± 0.01 vs 1.03 ± 0.14 for SREBP1; 1.65 ± 0.18 vs 3.63 ± 0.77 for nSREBP1, P < 0.05 for all). Furthermore, adipose tissue mass increased (22.4 g ± 3.6 g vs 12.0 g ± 2.6 g, P < 0.05)., Conclusion: The early insulin therapy induces a fat redistribution from liver to adipose tissue. The mechanism is probably through a reduction of ER stress and a down-regulated pathway of SREBP1 in liver of diabetic rats.

Objective: It was reported that a negative feedback loop might exist between peroxisome proliferator-activated receptor alpha (PPARalpha) and glucocorticoid receptor (GR). However, it is unclear whether GR expression is regulated by PPARalpha activation. To further demonstrate this possibility, we conducted the present study to investigate the regulatory effects of the PPARalpha agonist fenofibrate on GR expression in Sprague-Dawley rats., Methods: GR gene and protein expression levels were determined in liver, visceral and muscle tissues. Adrenal 11beta-hydroxylase (CYP11B1) expression was examined by RT-PCR and circulating corticosterone level was measured by RIA method., Results: GR expression was reduced by fenofibrate in a time- and does-dependent manner. The GR mRNA in the three fenofibrate groups of rats were 55% (FE1), 54% (FE2) and 68% (FE3) lower than that of the control rats. The GR protein were 28%, 77% and 99% lower than the control. The inhibition was observed in liver, but not in fat and muscle. The corticosterone level in the blood was increased significantly by fenofibrate(the levels of corticosterone in control, FE1, FE2, FE3, MK886 groups were (393 +/- 23), (495 +/- 44), (516 +/- 18), (622 +/- 93), (382 +/- 37) ng/ml respectively. These effects of fenofibrate were abolished by PPARalpha inhibitor MK886, suggesting that fenofibrate activated through PPARalpha., Conclusion: A new molecular mechanism has been found for a negative feedback regulation of GR activity by PPARalpha in SD rats.

Objective: To investigate the effect of early insulin therapy on the nuclear factor kappaB (NF-kappaB) pathway and inflammatory cytokine responses in skeletal muscle in type 2 diabetes mellitus (DM)., Methods: SD rats underwent intraperitoneal injection of streptozotocin to establish DM models and then divided into 5 groups: early un-treated group, early gliclazide treated group (receiving gliclazide since the third day after blood glucose increase for 3 weeks for 3 weeks), early insulin treated group (receiving insulin since the third day after blood glucose increase for 3 weeks for 3 weeks), late un-treated group, and late insulin treated group (receiving insulin since the fourth week after blood glucose increase for 3 weeks). By the end of treatment the rats were killed. Homogenate of skeletal muscle was made. The NF-kappaB P65 DNA binding was assayed by ELISA-based assay kit. Real time PCR was used to detect the mRNA expression levels of the gene of the cytokines: glucose transporter 4 (Glut4), inhibitor kappaB (IkappaBalpha), IL-1beta, IL-6, and tumor necrosis factor (TNF)-alpha. And Glut4 and IkappaBalpha protein expression levels were assayed by Western blotting., Results: The Glut4 mRNA level in the skeletal muscle of the untreated DM rats decreased by 59% and the Glut4 protein level in the muscle cell membrane decreased by 69%. Insulin treatment and gliclazide treatment increased the Glut4 mRNA expression by 17% and 13% respectively, increased the Glut4 protein expression in cell membrane by 23% and 10% respectively, and decreased the Glut4 protein expression in the cytoplasm. In the DM rats the IkappaBalpha protein expression in the skeletal muscle was significantly lower (P < 0.05) and the NF-kappaB P65 DNA binding activity increased, and TNF-alpha, IL-1B, and IL-6 expression levels were up-regulated in comparison with the normal control group. Early treatment of insulin and gliclazide increased the IkappaBalpha protein expression, decreased the NF-kappaB P65 DNA binding activity and the TNF-alpha expression in the skeletal muscle., Conclusion: Early insulin treatment inhibits the NFkappaB activity and inflammatory cytokine responses in skeletal muscle that are involved in the amelioration of insulin resistance in type 2 DM. Such results may be due to indirect antiinflammatory effects of insulin relieving glucotoxicity and lipotoxicity in peripheral tissues.