Molecular mechanism of the inhibition effect of Celecoxib on corneal collagen degradation in three dimensions

AIM: To clarify the molecular mechanism of Celecoxib on corneal collagen degradation and corneal ulcer. METHODS: Rabbit corneal fibroblasts were harvested and suspended in serum-free MEM. Type I collagen, DMEM, collagen reconstitution buffer and corneal fibroblast suspension were mixed on ice. The resultant mixture solidify in an incubator, after which test reagents and plasminogen was overlaid and the cultures were returned to the incubator. The supernatants from collagen gel incubations were collected and the amount of hydroxyproline in the hydrolysate was measured. Immunoblot analysis of MMP1, 3 and TIMP1, 2 was performed. MMP2, 9 was detected by the method of Gelatin zymography. Cytotoxicity Assay was measured. RESULTS: Celecoxib inhibited corneal collagen degradation in a dose and time manner; Celecoxib inhibited the IL-1 beta induced increases in proMMP1, 2, 3, 9 and active MMP1, 2, 3, 9 in a concentration-depended manner. Celecoxib can also inhibit the IL-1 beta induced increases in the TIMP1, 2. CONCLUSION: Celecoxib can inhibit corneal collagen degradation induced by IL-1 beta, this effect is the consequence of the reduction of MMP1, 2, 3, 9 and TIMP1, 2. The results of the present study provide new insight into Celecoxib in cornela ulcer treatment.

Modified Xiaochaihu Decoction(加味小柴胡汤) Promotes Collagen Degradation and Inhibits Pancreatic Fibrosis in Chronic Pancreatitis Rats

Objective:To investigate the effect of Modified Xiaochaihu Decoction(MXD,加味小柴胡汤)on collagen degradation in rats with chronic pancreatitis(CP).Methods:Rats were injected dibutyltin dichloride(DBTC,7 mg/kg of body weight)into the right caudal vein to induce CP model.Thirty heallhy male Wistar rats were randomly divided into three groups by a random number table:the control,the model and the treatment groups.Rats of treatment group were administered MXD(10 g/kg of body weight)orally once daily starting from the day post-model establishment.Pancreatic tissues were harvested after 28-day feeding and fibrosis was evaluated by picro-sirius red staining.The contents of collagen typeⅠandⅢwere detected using enzymelinked immunosorbent assay(ELISA),the expression of matrix metalloproteinase 13(MMP13)and tissue inhibitor of metalloproteinase 1(TIMP1)was analyzed by Western blot and real-time polymerase chain reaction(PCR).Results:The fibrosis scoring of pancreatic tissues,the concentrations of collagen typeⅠandⅢ,the expression levels of MMP13 and TIMP1 proteins and mRNA in the model group were all increased compared with the control group(P<0.05).After treatment with MXD,the fibrosis scoring of pancreatic tissues,the concentrations of collagen typeⅠandⅢ,the expression levels of MMP13 proteins and m RNA in the teatment group were all decreased compared with the model group(P<0.05),but there were no significant differences in the expression levels of TIMP1 proteins and m RNA(P>0.05).Conclusion:MXD could promote collagen degradation and reverse pancreatic fibrosis in CP rats via a mechanism involve up-regulation of MMP13 expression.

Dietary protein levels changed the hardness of muscle by acting on muscle fiber growth and the metabolism of collagen in sub-adult grass carp(Ctenopharyngodon idella)

Background:Nutrient regulation has been proven to be an effective way to improve the flesh quality in fish.As a necessary nutrient for fish growth,protein accounts for the highest proportion in the fish diet and is expensive.Although our team found that the effect of protein on the muscle hardness of grass carp was probably related to an increased collagen content,the mechanism for this effect has not been deeply explored.Moreover,few studies have explored the protein requirements of sub-adult grass crap(Ctenopharyngodon idella).Therefore,the effects of different dietary protein levels on the growth performance,nutritional value,muscle hardness,muscle fiber growth,collagen metabolism and related molecule expression in grass carp were investigated.Methods:A total of 450 healthy grass carp(721.16±1.98 g)were selected and assigned randomly to six experimen-tal groups with three replicates each(n=25/replicate),and were fed six diets with 15.91%,19.39%,22.10%,25.59%,28.53%and 31.42%protein for 60 d.Results:Appropriate levels of dietary protein increased the feed intake,percentage weight gain,specific growth rate,body composition,unsaturated fatty acid content in muscle,partial free amino acid content in muscle,and muscle hardness of grass carp.These protein levels also increased the muscle fiber density,the frequency of new muscle fibers,the contents of collagen and IGF-1,and the enzyme activities of prolyl 4-hydroxylases and lysyloxidase,and decreased the activity of matrix metalloproteinase-2.At the molecular level,the optimal dietary protein increased col-lagen type Iα1(Colα1),Colα2,PI3K,Akt,S6K1,La ribonucleoprotein domain family member 6a(LARP6a),TGF-β1,Smad2,Smad4,Smad3,tissue inhibitor of metalloproteinase-2,MyoD,Myf5,MyoG and MyHC relative mRNA levels.The levels of the myostatin-1 and myostatin-2 genes were downregulated,and the protein expression levels of p-Smad2,Smad2,Smad4,p-Akt,Akt,LARP6 and Smad3 were increased.Conclusions:The appropriate levels of dietary protein promoted the growth of sub-adult grass carp and improved muscle hardness by promoting the growth of muscle fibers,improving collagen synthesis and depressing collagen degradation.In addition,the dietary protein requirements of sub-adult grass carp were 26.21%and 24.85%according to the quadratic regression analysis of growth performance(SGR)and the muscle hardness(collagen content),respectively.

Role of corneal collagen fibrils in corneal disorders and related pathological conditions

The cornea is a soft tissue located at the front of the eye with the principal function of transmitting and refracting light rays to precisely sense visual information. Corneal shape, refraction, and stromal stiffness are to a large part determined by corneal fibrils, the arrangements of which define the corneal cells and their functional behaviour. However, the modality and alignment of native corneal collagen lamellae are altered in various corneal pathological states such as infection, injury, keratoconus, corneal scar formation, and keratoprosthesis. Furthermore, corneal recuperation after corneal pathological change is dependent on the balance of corneal collagen degradation and contraction. A thorough understanding of the characteristics of corneal collagen is thus necessary to develop viable therapies using the outcome of strategies using engineered corneas. In this review, we discuss the composition and distribution of corneal collagens as well as their degradation and contraction, and address the current status of corneal tissue engineering and the progress of corneal cross-linking.

Potential Role of Astragaloside IV in the Treatment of Fungal Keratitis

Fungal keratitis (FK) is a worldwide visual impairment disease. The pathogenesis of fungal keratitis involves fungi, corneal cells, inflammatory cell infiltration, collagen degradation, inflammatory cytokines and their interactions. Accumulated evidence indicated that Astragaloside IV (AS-IV) possesses a broad range of pharmacological properties, such as efficacy in anti-inflammation, alleviating fibrosis, and immunomodulatory effects. This paper summarizes new findings regarding AS-IV in immune and inflammatory diseases and analyzes the perspective application of Astragaloside IV in fungal keratitis.

MACROPHAGES IN DEGRADATION OF COLLAGEN / HYDROXYLAPATITE(CHA), BETA-TRICALCIUM PHOSPHATE CERAMICS (TCP) ARTIFICIAL BONE GRAFT AN IN VIVO STUDY

The macrophages mediated biodegradation of two biomaterials, collagen / hydroxylapatite (CHA) and beta-tricalcium phosphate ceramics (TCP), was studied in 24 male Kunming mice and 20 male C57BL / 6 mice with histopathologic, histochemical and ultrastructural observation. It was demonstrated that macrophages infiltrated after CHA, TCP were implanted. The macrophages could be differentiated from fibroblasts and the other infiltrated cells for special cellular profile and strong acid phosphatase activity. Morphologically, monocyte macrophages and infused multinuclear giant cell degraded CHA and TCP by phagocytosis and extracellular resorption. The carbonic anhydrase activity of macrophages was demonstrated by histochemical technique. It suggested that macrophages secreted H+ and accomplished the decalcification of calcium phosphate compound of CHA and TCP. We conclude that macrophages are the main mediating cells which degraded CHA and TCP intracellularly and extracellularly.