High-dose Vitamin C injection ameliorates against sepsis-induced myocardial injury by anti-apoptosis, anti-inflammatory and pro-autophagy through regulating MAPK, NF-κB and PI3K/AKT/mTOR signaling pathways in rats.

AIMS: This study aimed to evaluate the effects of VC on SIMI in rats. METHODS: In this study, the survival rate of high dose VC for SIMI was evaluated within 7 days. Rats were randomly assigned to three groups: Sham group, CLP group, and high dose VC (500 mg/kg i.v.) group. The animals in each group were treated with drugs for 1 day, 3 days or 5 days, respectively. Echocardiography, myocardial enzymes and HE were used to detect cardiac function. IL-1ß, IL-6, IL-10 and TNF-α) in serum were measured using ELISA kits. Western blot was used to detect proteins related to apoptosis, inflammation, autophagy, MAPK, NF-κB and PI3K/Akt/mTOR signaling pathways. RESULTS: High dose VC improved the survival rate of SIMI within 7 days. Echocardiography, HE staining and myocardial enzymes showed that high-dose VC relieved SIMI in rats in a time-dependent manner. And compared with CLP group, high-dose VC decreased the expressions of pro-apoptotic proteins, while increased the expression of anti-apoptotic protein. And compared with CLP group, high dose VC decreased phosphorylation levels of Erk1/2, P38, JNK, NF-κB and IKK α/ß in SIMI rats. High dose VC increased the expression of the protein Beclin-1 and LC3-II/LC3-I ratio, whereas decreased the expression of P62 in SIMI rats. Finally, high dose VC attenuated phosphorylation of PI3K, AKT and mTOR compared with the CLP group. SIGNIFICANCE: Our results showed that high dose VC has a good protective effect on SIMI after continuous treatment, which may be mediated by inhibiting apoptosis and inflammatory, and promoting autophagy through regulating MAPK, NF-κB and PI3K/AKT/mTOR pathway.

[Establishment and significance of the experimental minimal persistent inflammation models in allergic rhinitis guinea pigs].

OBJECTIVE: To develop an animal model of minimal persistent inflammation (MPI) in allergic rhinitis guinea pigs and to investigate its significance. METHODS: Sixty male Hartley guinea pigs were divided into four groups: group A (positive control group), B (MPI model group), C (negative group) and D (bland group) respectively, with fifteen animals in each group. Guinea pigs from group A, B and C were sensitized intraperitoneally by injection of suspension of ovalbumin (OVA) and aluminum hydroxide in 0.9% physiological saline. Then, repeated local booster sensitization with different concentration of OVA suspension (1% and 0.01%) or physiological saline into the nasal cavity of those guinea pigs were performed. For group D, physiological saline was used only. Symptoms (sneezing) of guinea pigs after antigen challenge were observed and the infiltration of eosinophils (EOS) together with the expression of intercellular adhesion molecule 1 (ICAM-1) in the nasal epithelial cells were also examined. RESULTS: When challenged with 1% OVA, the sneezing number of guinea pigs in group B was increased markedly than that in group D (P < 0.05). However, there was no difference between group B, A and C (P > 0.05). When challenged with 0.01% OVA, the symptom of sneezing almost disappeared in group B just like that in group D and there was no difference between the two groups (P > 0.05). Besides, there was still more EOS infiltrated in the nasal mucosa of guinea pigs in group B than that in group D (P < 0.05). There was no expression of ICAM-1 in nasal epithelium of guinea pigs in group D, nevertheless, ICAM-1 was found mildly expressed in group B. CONCLUSIONS: MPI models have been established successfully through long term challenge with lower density of OVA in the sensitized guinea pigs, which will provide us with a new method for further research in the mechanism and treatment of allergic rhinitis.

[Effects of minimal persistent inflammation on nasal mucosa of experimental allergic rhinitis in guinea pigs].

OBJECTIVE: To establish an animal model of minimal persistent inflammation (MPI) of allergic rhinitis in guinea pigs and to investigate the changes of nasal mucosa. The expression of transforming growth factor-beta1 (TGF-beta1) and matrix metalloproteinases-9 (MMP-9) were discussed. METHODS: Thirty male Hartley guinea pigs were randomly divided into two groups: MPI model group and control group randomly, with fifteen animals in each group. Guinea pigs from MPI model group were sensitized intraperitoneally by injection of suspension of ovalbumin (OVA) and aluminum hydroxide in 0.9% physiological saline. Then, repeated local booster sensitization with low concentration of OVA suspension into the nasal cavity was performed to establish MPI models. Alcian blue-periodic acid-Schiff (AB-PAS) staining and Masson's trichrome (MT) staining were used to determine the number of goblet cells and collagen deposition within the basement membrane of epithelium. The expression and distribution of TGF-beta1 and MMP-9 in nasal mucosa were estimated by double immunofluorescence under a confocal laser scan microscopy system. RESULTS: Compared with the control group, the increased goblet cells (t = 13.720, P < 0.05) in nasal epithelium together with the increased collagen fibrils (t = 4.542, P <0.05) within the basement membrane of epithelium were observed in the MPI model group. There was nearly no expression of TGF-beta1, in the control group and the expression of MMP-9 was only found in the epithelium cell. In contrast, there was significantly higher expression of TGF-beta1 and MMP-9 (t = 25.218, P <0.05) in nasal mucosa of MPI model group than that in control group. TGF-beta1 mainly expressed in the epithelium cell, the infiltrated inflammatory cell and extracellular matrix, while MMP-9 expressed in the epithelium cell and the infiltrated inflammatory cell. CONCLUSIONS: Long time MPI in allergic rhinitis resulted in some changes of tissue remodeling in nasal mucosa. TGF-beta1 and MMP-9 may play an important role in disease progression.

[Expression of proto-oncogenes c-fos and c-jun in osteoblasts activated by excessive fluoride].

OBJECTIVE: To study expression of proto-oncogenes c-fos and its accompanying gene c-jun in osteoblasts activated by action of excessive fluoride in vivo and in vitro. METHODS: Experimental Wistar rats were exposed to sodium fluoride (NaF) added to their drinking water, and NaF was also added in cell culture supernatant for osteoblast-like cells in vitro. Expression of both mRNA and protein of c-fos and c-jun in bone-tissue of rats with chronic fluorosis and cultured osteoblast-like cells were determined by hybridization in situ, Western blot and immunohistochemistry at varied time periods after exposure. RESULTS: Sodium fluoride could stimulate the proliferation of osteoblast in rats with chronic fluorosis and induce expression of both c-fos and c-jun in all envelops of the spine bone, as compared with its control group. Value of optical absorption in mRNA expression of c-fos and c-jun was 139.63 and 126.37, respectively, in rats with NaF plus high-calcium, significantly lower than that in control group with high-calcium only (107.74 and 117.48, respectively) (P < 0.001). Immunohistochemical analysis showed that protein level of c-fos and c-jun was significantly higher in rats with NaF plus high-calcium than that in control rats with high-calcium only, with values of optical absorption of 139.16, 131.15, 149.98 and 149.19 (P < 0.05), respectively, and protein level of c-fos and c-jun was significantly higher in rats with NaF plus low-calcium than that in control rats with low-calcium only, with values of optical absorption of 117.24, 111.46, 132.46 and 129.79 (P < 0.05), respectively. Western blotting showed that level of protein expression of c-fos and c-jun in periosteal osteoblasts was significantly higher in all rat groups with NaF than that in all control groups, with values of optical absorption of 123.32, 116.60, 115.97 and 108.30, respectively. mRNA expression of c-fos and c-jun in osteoblast-like cells treated with NaF for 12 h increased obviously, and remained at high level 48 h after exposure, with values of optical absorption of 114.80, 161.14, 118.20, and 150.41, respectively, as compared with that in control group (P < 0.001 and P < 0.05). CONCLUSIONS: Exposure to excessive fluoride could stimulate activation and proliferation of both osteoblasts in rats and cultured osteoblast-like cells in vitro, and cause enhanced expression of mRNA and protein of both c-fos and c-jun. Over-expression of c-fos could play an important role in development and proliferation of skeletal lesions in rats with chronic fluorosis.