Rat Granulation Research Articles

Effect of Taspine hydrochloride on the repair of rat skin wounds by regulating keratinocyte growth factor signal

ABSTRACT To explore the regulation of keratinocyte growth factor (KGF) in the process of repairing rat skin wounds by taspine hydrochloride (TA/HCl), 45 male Sprague-Dawley (SD) rats were purchased and divided into an experimental group, a dimethyl sulfoxide (DMSO) control group, and a basic fibroblast growth factor (bFGF) control group, each with 15 only. A back trauma model was innovatively adopted to prevent rats from biting and contaminating. The wound healing time and healing rate of the rat, and the Hydroxyproline (Hyp) and KGF expressions were observed. Morphological changes of wound tissue and the number of capillaries were observed after hematoxylin-eosin (HE) staining. The results showed that wound healing rate of experimental group and bFGF group was significantly higher than that of DMSO group (P < 0.05) after 2–15 days, and wound healing time of experimental group was 18 days, which was significantly lower than that of the DMSO group (P < 0.05). Expression levels of Hyp and KGF in the granulation tissue of rats in the experimental group were much higher than those in the DMSO control group after trauma (P < 0.05). In early stage of wound tissue repair, the number of new capillaries formed in experimental group was significantly higher than that in DMSO control group (P < 0.05). In summary, this study innovatively focused on KGF. The mechanism of TA/HCL promoting rat skin wound healing was closely related to KGF.

Effects of temperature-sensitive hydroxybutyl chitosan hydrogel on wound healing of full-thickness skin defect in rats

Effects of temperature-sensitive hydroxybutyl chitosan hydrogel on wound healing of full-thickness skin defect in rats

EFFECT OF CHANNA MICROPELTES IN THE GRANULATION, FIBROSIS AND NECROSIS OF DIABETIC WOUND HEALING

Background: Diabetes mellitus (DM) is characterized by persistent hyperglycemia. The symptoms of DM is delayed wound healing. Delayed wound healing in diabetes will increase the risk of wound complications that will hinder the healing process, and lead to complications such as fibrosis and necrosis. The use of Channa Micropeltes (CM) extract at a dose of 16 mL/kg BW orally is proven to general optimal wound closure and wound contraction clinically in Wistar rats as diabetic model on day 14.However, the histopathological description of wound healing is yet to be known. Objective: To analyze the effect of 16 mL/kg BW dose of CM extract on histopathological changes of wound healing granulation tissue, fibrosis and necrosis in diabetic Wistar rats on day 14. Materials and Methods: This study was a true experimental design with a post-test only control group design. The samples were divided into two groups, namely the diabetic model group given CM extract at 16 mL/kg BW dose for 14 days, and the diabetic model group given BR2 feed only for 14 days. Results: The results of Mann-Whitney U test showed p = 0.003 for granulation tissue, p = 0.411 for fibrosis and p = 1 for necrosis, with the level of significance was p&lt;0.05. Conclusion: The CM extract at 16 mL/kg BW dose affects the histopathological description of granulation tissue which presents a better result than those in the control group but did not affect the features of fibrosis and necrosis in diabetic Wistar rats on day 14. Keywords: Channa Micropeltes, Diabetic wound, Fibrosis, Granulation tissue, Necrosis.

Cutaneous Regeneration Mechanism of β-Sheet Silk Fibroin in a Rat Burn Wound Healing Model.

Therapeutic dressings to enhance burn wound repair and regeneration are required. Silk fibroin (SF), a natural protein, induces cell migration and serves as a biomaterial in various dressings. SF dressings usually contain α-helices and β-sheets. The former has been confirmed to improve cell proliferation and migration, but the wound healing effect and related mechanisms of β-sheet SF remain unclear. We investigated the effects of β-sheet SF in vivo and in vitro. Alcohol-treated α-helix SF transformed into the β-sheet form, which promoted granulation formation and re-epithelialization when applied as lyophilized SF dressing (LSFD) in a rat burn model. Our in vitro results showed that β-sheet SF increased human dermal fibroblast (HDF) migration and promoted the expression of extracellular matrix (ECM) proteins (fibronectin and type III collagen), matrix metalloproteinase-12, and the cell adhesion molecule, integrin β1, in rat granulation tissue and HDFs. This confirms the role of crosstalk between integrin β1 and ECM proteins in cell migration. In summary, we demonstrated that β-sheet SF facilitates tissue regeneration by modulating cell adhesion molecules in dermal fibroblasts. LSFD could find clinical application for burn wound regeneration. Moreover, β-sheet SF could be combined with anti-inflammatory materials, growth factors, or antibiotics to develop novel dressings.

Wound Healing Activities of Latex of Grassleaf Spurge (&lt;i&gt;Euphobia &lt;/i&gt;&lt;i&gt;g&lt;/i&gt;&lt;i&gt;raminea&lt;/i&gt;&lt;i&gt; &lt;/i&gt;Jacq.)

The present study evaluated the wound healing potentials of E. graminea (EG) latex. The latex of EG was screened for the presence of phytochemical constituents; in vitro antioxidant property and erythrocyte membrane stabilizing activity was used to investigate anti-inflammatory property of the latex. The wound healing potential of E. graminea latex (EGL) was investigated via incision and dead space wound models in wistar rats; eighteen wistar rats (separately for each model) were randomly divided into 3 groups (6 in each group): Group A: wound + EGL ; Group B: wound + Gentamycin (G); Group C: wound without treatment (control). Wound breaking strength (Incision model), hexuronic acid and hexosamine concentrations, activities of antioxidants biomolecules (superoxide dismutase, catalase, and reduced glutathione) as well as the levels of free radicals (nitric oxide-NO, malondialdehyde -MDA) were evaluated in the granulation tissue (dead space model) of experimental rats. The result of the study revealed that EGL tested positive for the presence of saponins, alkaloids, triterpenes, flavonoids and cardiac glycosides. Also, EGL contained an appreciable concentration of total flavonoids and phenolics. The latex exhibited mild ferric reducing power, inhibited DPPH in dose dependent manner as well as protected red blood cells against hypotonic and heat induced lyses. In wound incision model, EGL exhibited 13.6 % increase in wound breaking strength when compared to the control animals. Also, in dead space wound model, there was significant increase (p < 0.05) in hexoxamine, hexuronic acid and GSH concentrations as well as SOD activity in EGL and gentamycin treated wound compared to the control. Furthermore, there was a significant reduction (p < 0.05) in MDA concentration in EGL and gentamycin treated wound compared to the control while NO level and catalase activity showed no significant difference. This study revealed that EGL contained potentially bioactive molecules that could be employed in the treatment of wound.

Evaluation of bacteriophage products against burn wound Methicillin-resistant Staphylococcus aureus (MRSA) infections

Abstract Background The major problem in the management of burn wounds are infections. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major cause of infection in burn wounds. Antibiotic resistant bacteria around the world has become a major therapeutic challenge. Bacteriophages and their lysine are suggested as an antimicrobial alternative agent. Phage display technique is suggested for production of recombinant lysine by Nano carrier technology. The approach of this study was to evaluate the potential of recombinant Nano phage efficacy in MRSA burn wound infection in vivo. Materials and methods The 3rd degree burn wounds were induced in 54 rats and infected with MRSA ATCC 33591 via the topical route in four groups. Burn wound size was measured in 0, 14, 21, 28 days. The efficacy of Nano phage gel was assessed on the basis of percentage collagen deposition, granulation tissue, neovascularization, fibroblastic maturity, re-epithelization, and scar formation in rats following treatment in 14, 21, 28 days. Results The results showed that the percentage of wound size were 3 cm on base line day and the average macroscopic wound healing rates were increased in the prevention groups receiving the recombinant Nano phage gel and natural phage gel, in the treatment groups with secondary infection receiving the recombinant Nano phage gel and the natural phage gel, and in the two control groups respectively. The average microscopic wound healing rates were increased in the prevention groups receiving the recombinant Nano phage gel and natural phage gel, in the treatment groups with secondary infection receiving the recombinant Nano phage gel and the natural phage gel, and in the two control groups respectively. Conclusions In conclusion the recombinant Nano phage gel is efficacy to treat and prevent MRSA burn wound infection.

Topically injected adrenocorticotropic hormone induces mechanical hypersensitivity on a full-thickness cutaneous wound model in rats.

Cutaneous wound pain causes physical and psychological stress for patients with wounds. Previous studies reported that stress induces hyperalgesia and deteriorates wound healing. However, the effect of the stress response such as in hypothalamic-pituitary-adrenal (HPA) axis on local wound area is unclear. We aimed to investigate the effects of a stress response on the mechanical withdrawal threshold in the local wound area and describe the identification of a wound pain exacerbation. We topically injected adrenocorticotropic hormone (ACTH) into the granulation tissue of full-thickness cutaneous wound model rats on the fifth day postwounding and measured the mechanical withdrawal thresholds, cytochrome P450 2Bs levels and concentration of 5,6-epoxyeicosatrienoic acid in wound exudate. We found that ACTH induced mechanical hypersensitivity at 4 and 6hours after injection (P=.004 and .021, respectively), and increased gene expression of cytochrome P450 2B12 expression (P=.046). Concentration of 5,6-EET in the wound exudate was moderately correlated with the mechanical withdrawal threshold (r=-.630). Finally, the mechanical withdrawal threshold in the 5,6-EET group was significantly lower than that in the control group at 2hours after the injection (P=.015). We propose that 5,6-EET is one of the most promising contributors to the wound pain exacerbation. These findings could guide clinical wound and pain management.

Age-associated impairments in tissue strength and immune response in a rat vaginal injury model.

Surgical repair of pelvic organ prolapse often includes native tissue repair during which the patient's own vaginal connective tissue is used to achieve pelvic support. This method, based on plication and suspension often yields suboptimal anatomical outcomes, possibly due to inadequate healing of the vaginal connective tissue. We hypothesized that age might have a negative effect on the time course and tissue biomechanics of vaginal wound healing in a rat model. Fifty young (12weeks) and old (12months) female 344BN Fischer rats were subjected to a posterior midline vaginal incision. The time course of repair was determined by measuring the size of the wound on days 1, 3, 7, and 14 post-injury. These findings correlated with the immune response to injury using a marker of impaired wound healing, the inflammatory cytokine macrophage migration inhibitory factor in the vaginal muscularis. Biomechanical properties of the healed vaginal tissue were tested 30days post-injury. Wound healing was assessed on days 1, 3, 7, and 14 post-injury. On day 3 post-injury, the wounds in the young animals had all closed whereas the wounds in the old animals remained open. Furthermore, on day 7, the wound gap was still filled with granulation tissue in the old rats, whereas for the young rats, the wound area was almost indistinguishable from the non-injured area. Macrophage migration inhibitory factor was highly expressed in the vaginal epithelium and in the vaginal muscularis after injury. When compared with young animals, macrophage migration inhibitory factor levels of old rats began to rise more than 2days later and the increased tissue expression persisted for 7days longer. The breakpoint force of the healed vagina of old rats was almost 4-fold weaker than in young rats. At 30days post-injury, the healed vagina in old rats regained less of the original (healthy) force at breakpoint than the young rats. In this rat model, age impaired vaginal wound healing, which was reflected in the altered inflammatory response to injury and reduced tissue strength.

Quercetin and low level laser therapy promote wound healing process in diabetic rats via structural reorganization and modulatory effects on inflammation and oxidative stress

This study aimed to evaluate the effect of quercetin and the photo-stimulatory effect of low energy 632.8 nm laser irradiation on excisional wound healing in non-diabetic and diabetic rats. Streptozotocin (45 mg/kg body weight) was intraperitoneally applied for diabetes induction. A full-thickness skin wound (2 × 2 cm2) was aseptically created with a scalpel in non-diabetic and diabetic rats on the shaved back of the animals. The wounded non-diabetic and diabetic rats were treated every other day with quercetin by oral gavage at dose 25 mg/kg body weight and/or with low level laser therapy (LLLT) for 14 days. The wound closure percent calculated during the course of the experiment at days 1, 7 and 14 was remarkably increased as a result of treatment of non-diabetic and diabetic wounded rats with quercetin and LLLT; the treatment with both was the most potent. The elevated blood glucose and the lowered serum insulin levels were significantly improved in diabetic wounded rats treated with quercetin and LLLT as compared to the diabetic wounded control. The histological findings indicated that the wounded skin showed a marked increase in collagen fibers which become well oriented in sub-epidermal tissue, intact epidermis and presence of hyperplasia covering well-developed granulation tissue in the wounded rats treated with quercetin and LLLT as compared to the corresponding wounded control. The elevated levels of serum pro-inflammatory cytokines, IL-1β and TNF-α, as well as PGE-2 and LTB-4 were decreased in non-diabetic and diabetic wounded rats with quercetin and LLLT while the lowered level of serum anti-inflammatory cytokine, IL-10, was increased. The augmented oxidative stress represented by increased serum lipid peroxides level was decreased and the serum level of non-enzymatic anti-oxidant glutathione was increased as a result of treatment with quercetin and LLLT. Thus, it can be suggested that the improvements in glycemic state, cytokines involved in inflammation and antioxidant defense system as well as structural reorganization after treatment with quercetin and LLLT may play pivotal roles in promoting the wound healing process. The study also concluded that the treatment with quercetin in association with LLLT was better in improving wound healing in non-diabetic and diabetic rats than the use of either of each.

Fabrication of electropsun PLGA and small intestine submucosa-blended nanofibrous membranes and their biocompatibility for wound healing

In recent decades, tremendous research has focused on the production of nanoscale fibers using synthetic polymers, with the goal of fabricating nanofibrous scaffolds for wound healing. However, the hydrophobicity of such polymers typically hinders attachment and proliferation of the cells. In this study, we combined poly-d,l-lactide-co-glycolide (PLGA) and small intestine submucosa (SIS) to fabricate blended nanofibers for wound healing by electrospinning. PLGA and SIS were dissolved in 1,1,1,3,3,3-hexafluoro isopropanol to produce different weight ratios of PLGA/SIS-blended nanofibrous membranes (NFM). Physicochemical characterization of the electrospun NFM was performed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, water contact angle analysis, degradation test and tensile testing. The PLGA/SIS-blended NFM showed improved hydrophilicity and tensile strength. Better infiltration, attachment and proliferation of rat granulation fibroblasts of PLGA/SIS-blended NFMs compared to PLGA NFMs were identified by morphological differences determined by SEM and a water-soluble tetrazolium salt assay kit. Based on our results, the PLGA/SIS blended NFMs were found to be suitable for use as a potential material for wound dressing.

Comparative study on the anti-inflammatory and immune suppressive effect of Wilforlide A

Tripterygium Glycosides (TG) is effective in the treatment of patients with a variety of inflammatory and autoimmune diseases, especially rheumatoid arthritis (RA) in clinical. Wilforlide A (T 1) serves as a quality control standard of TG that be listed in Drug Standard of Ministry of Public Health of the People's Republic of China. The pharmacologic actions of T 1 remain to be unidentified. In this paper, we studied the anti-inflammatory and immune suppressive effect of T 1, and compared it with Triptolide (TP), which believed to be the major active component of TG. Carrageenan-induced rat pedal swelling, tampon-induced rat granulation, and mice ear inhibition rate of swelling trail results show that high-dose T 1 has obvious anti-inflammatory effect. Colorimetric detection contents of hemolysin, carbon elimination from plasma of mice, mice delayed hypersensitivity immune, and organ index were measured. The results show that T 1 has no significant immune suppressive activity, and there has a significant difference with TP and TG. Therefore, we think the content of TP also should be controlled as a supplement standard in order to ensure safe and effective medication.

NF-κB blockade upregulates Bax, TSP-1, and TSP-2 expression in rat granulation tissue

Several diseases are characterized by chronic inflammation, a condition frequently associated with angiogenesis and fibrogenesis that account for the development of granulation tissue. Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) is a crucial modulator of intracellular prosurvival signaling pathways and is implicated in the pathogenesis of inflammatory process. In this study, we have investigated the role of NF-kappaB in the angiogenic and fibrogenic response induced by lambda-carrageenin in a rat model of chronic inflammation at 1, 3, and 5 days. The subcutaneous implant of lambda-carrageenin-soaked sponges in rat induced a time-related increase of granulation tissue formation accompanied by intense neovascularization. These lambda-carrageenin-induced changes were significantly reduced by coinjection of wild-type oligodeoxynucleotide (WT ODN) decoy to NF-kappaB. Molecular, morphological, and ultrastructural analysis performed on whole granulation tissue demonstrated: (1) inhibition of NF-kappaB/DNA binding activity; (2) downregulation of cyclooxygenase-2, matrix metalloproteinase-9, tumor necrosis factor-alpha, and vascular endothelial growth factor; (3) upregulation of thrombospondin (TSP)-1 at 1 day and TSP-2 at 5 days; and (4) increase in Bax to Bcl-2 ratio. Our findings show that the blockade of NF-kappaB activation by WT ODN decoy prevents the development of granulation tissue induced by lambda-carrageenin-soaked sponge implant upregulating Bax as well as TSP-1 and TSP-2 expression.

Does Rat Granulation Tissue Maturation Involve Gap Junction Communications?

Does Rat Granulation Tissue Maturation Involve Gap Junction Communications?

Effects of reinforcing qi and nourishing blood recipes on vascular endothelial growth factor and microvessel count in granulation tissue in rats with chronic skin ulcers

To explore the effects of reinforcing qi and nourishing blood recipes on vascular endothelial growth factor (VEGF) and the microvessel count (MVC)in granulation tissue in rats with chronic skin ulcers. A total of 90 male SD rats with back full-thickness skin lesion were used in this study. Except for the normal control group, the rats were injected with hydrocortisone for inducing chronic skin ulcers, and were randomly divided into untreated group, Sijunzi Decoction group, Siwu Decoction group and Bazhen Decoction group. The time of wound healing was observed; immunohistochemical method and image analytical method were used to test the expressions of VEGF and MVC in granulation tissue of dermal chronic ulcers in the rats. In the untreated group, the time of wound healing was significantly longer than that in the normal group (P<0.01). The time of wound healing was obviously shortened in the three treated groups as compared with the untreated group (P<0.01, P<0.05). In the Sijunzi Decoction group, the time of wound healing was obviously shorter than those in Siwu Decoction group and Bazhen Decoction group (P<0.05, P<0.01). In the untreated group, the expression of VEGF and MVC were significantly lower than those in the normal control group (P<0.01). The expression of VEGF and MVC were obviously increased in the three treated groups as compared with those in the untreated group (P<0.01, P<0.05). In the Sijunzi Decoction group, the expression of VEGF and MVC were obviously lower than those in Siwu Decoction group and Bazhen Decoction group (P<0.05, P<0.01). Reinforcing qi and nourishing blood recipes can promote wound healing in rats through up-regulating the expression of VEGF in granulation tissue of dermal chronic ulcers, and inducing angiogenesis.

Effects of resolving stagnation and promoting granulation therapy on expressions of Bax and Bcl-2 in granulation tissue of diabetic rats during wound healing

To study the effects of resolving stagnation and promoting granulation therapy on expressions of Bax and Bcl-2 in granulation tissue of diabetic rats during wound healing. Seventy-two male SD diabetic rats with full-thickness skin lesion were randomly divided into 3 groups: SJHYR 1-treated group, SJHYR 2-treated group and normal saline (NS) control group. SJHYR 1 was prepared with Shengji Recipe (SJR, a compound traditional Chinese herbal medicine for promoting granulation) and Huayu Recipe (HYR, a compound traditional Chinese herbal medicine for resolving stagnation) at a ratio of 1:2, while SJHYR 2 was prepared with SJR and HYR at a ratio of 1:1. Immunohistochemical method was used to assess Bax and Bcl-2 protein levels in granulation tissue. SJHYR 1 could accelerate wound healing as compared with SJHYR 2 and NS (P<0.05). On the third day in experiment, Bax and Bcl-2 proteins were not found in any groups, but on the seventh and eleventh day in experiment, Bax and Bcl-2 proteins in SJHYR 1-treated group were much higher than those in the other two groups (P<0.05). SJR and HYR in different ratios may all have a role in regulating Bax and Bcl-2 expression in granulation tissue of diabetic rats during wound healing.

Does Rat Granulation Tissue Maturation Involve Gap Junction Communications?

Wound healing, a coordinated process, proceeds by sequential changes in cell differentiation and terminates with the deposition of a new connective tissue matrix, a scar. Initially, there is the migratory fibroblast, followed by the proliferative fibroblast, then the synthetic fibroblast, which transforms into the myofibroblast, and finally the apoptotic fibroblast. Gap junction intercellular communications are proposed to coordinate the stringent control of fibroblast phenotypic changes. Does added oleamide, a natural fatty acid that blocks gap junction intercellular communications, alter the phenotypic progression of wound fibroblasts? Pairs of polyvinyl alcohol sponges attached to Alzet pumps, which constantly pumped either oleamide or vehicle solvent, were implanted subcutaneously into three rats. On day 8, implants were harvested and evaluated histologically and biochemically. The capsule of oleamide-treated sponge contained closely packed fibroblasts with little connective tissue between them. The birefringence intensity of that connective tissue was reduced, indicating a reduced density of collagen fiber bundles. Myofibroblasts, identified immunohistologically by alpha-smooth muscle actin-stained stress fibers, were reduced in oleamide-treated implants. Western blot analysis showing less alpha-smooth muscle actin confirmed the reduced density of myofibroblasts. It appears that oleamide retards the progression of wound repair, where less connective tissue is deposited, the collagen is less organized, and the appearance of myofibroblasts is impaired. These findings support the hypothesis that gap junction intercellular communications between wound fibroblasts in granulation tissue play a role in the progression of repair and the maturation of granulation tissue into scar.

Impaired integration of endothelial progenitor cells in capillaries of diabetic wounds is reversible with vascular endothelial growth factor infusion

To understand impaired angiogenesis in diabetic wounds, polyvinyl tubes were implanted subcutaneously in rats to form a granulation tissue for 2 weeks and the granulation tissue was studied after inducing diabetes with streptozotocin. By 1 week of diabetes, the granulation tissue was bloody and thinner than controls, its medial layer was depleted of microvessels, and the surviving vessels appeared dehisced. Vascular endothelial growth factor (VEGF) in the diabetic granulation tissue was reduced by 50% compared with control granulation tissue. After 3 days of diabetes, the diabetic tissue showed a greater degree of apoptosis in the microvessels. Chemotactic factors [stromal cell-derived factor-1alpha and chemokine receptor-4 (CXCR-4)], responsible for attracting bone marrow cells, showed equal intensity in control and diabetic tissues. As expected, progenitor endothelial CD-34 cells were observed in abundance in both the control and the diabetic granulation tissues. However, although the CD-34-positive cells appeared mostly to be integrated in the blood vessels of the control tissue, fewer such cells were present in the blood vessels of the diabetic tissues, suggesting that CD-34 failed to integrate into new blood vessels. Infusion of VEGF in the granulation tissue of diabetic rats for 1 week resulted in complete prevention of the microvascular defect compared with the contralateral granulation tissue that showed the typical diabetic changes. It was concluded that diabetes causes reduction of VEGF in the wound, resulting in loss of blood vessels by apoptosis and possible failure of CD-34 cells to integrate into the vessel structure.

Effects of Shengji Huayu Recipe and its decomposed formulas on synthesis of collagen types Ⅰ and Ⅲ in granulation tissue of rats in early wound healing

To study the effects of Shengji Huayu Recipe (a traditional Chinese medicine compound recipe for resolving stagnation and promoting granulation) and its decomposed formulas (Huayu Recipe for resolving stagnation and Shengji Recipe for promoting granulation) on the synthesis of collagen types I and III in granulation tissue of rats in early wound healing. Twenty-four male Sprague-Dawley (SD) rats with full-thickness skin lesion were randomized into 4 groups: Shengji Huayu Recipe-treated group, Shengji Recipe-treated group, Huayu Recipe-treated group and untreated group. Collagen types I and III in granulation tissue of the rats were tested with immunohistochemical methods and image analysis. On the third day of wound healing, collagen I of the rats in both Shengji Huayu Recipe-treated group and Shengji Recipe-treated group was higher than that in the untreated group, and collagen I of the rats in Huayu Recipe-treated group was lower than that in the untreated group (P<0.05). Collagen III of the rats in the three treated groups were lower than that in the untreated group (P<0.05). On the seventh day of wound healing, Collagen I of the rats in both Shengji Huayu Recipe-treated group and Shengji Recipe-treated group was higher than that in the untreated group (P<0.05), and collagen III of the rats in both Shengji Recipe-treated group and Huayu Recipe-treated group was higher than that in the untreated group (P<0.05). Resolving stagnation and promoting granulation therapy can promote the wound healing in rats.

Energy metabolism in the granulation tissue of diabetic rats during cutaneous wound healing

The skin cells chiefly depend on carbohydrate metabolism for their energy requirement during cutaneous wound healing. Since the glucose metabolism is greatly hampered in diabetes and this might affect wound repair process. This prompted us to investigate the intermediate steps of energy metabolism by measuring enzyme activities in the wound tissues of normal and streptozotocin-induced diabetic rats following excision-type of cutaneous injury. The activities of key regulatory enzymes namely hexokinase (HK), phosphofructokinase (PFK), lactate dehydrogenase (LDH), citrate synthase (CS) and glucose-6 phosphate dehydrogenase (G6PD) have been monitored in the granulation tissues of normal and diabetic rats at different time points (2, 7, 14 and 21 days) of postwounding. Interestingly, a significant alteration in all these enzyme activities was observed in diabetic rats. The activity of PFK was increased but HK, LDH and CS showed a decreased activity in the wound tissue of diabetics as compared to normal rats. However G6PD exhibited an elevated activity only at early stage of healing in diabetic rats. Thus, the results suggest that significant alterations in the activities of energy metabolizing enzymes in the wound tissue of diabetic rats may affect the energy availability for cellular activity needed for repair process and this may perhaps be one of the factor responsible for impaired healing in these subjects.

Ovariectomy Reduces the Gelatinolytic Activity and Expression of Matrix Metalloproteinases and Collagen in Rat Molar Extraction Wounds

Osteoporosis is commonly associated with estrogen deficiency. However, the mechanisms by which the lack of this hormone causes bone loss are poorly understood. The bone structure of the oral cavity seems to be affected by estrogen deficiency, since a delayed healing process after tooth extraction has been observed after ovariectomy in rats. The aim of this study was to describe the effect of the absence of estrogen on the expression and activity of matrix metalloproteinases (MMC)-2 and -9 and expression of types I and III collagens in the alveolar granulation tissue of young female rats after tooth extraction. Sixty-six, four-week-old female rats underwent bilateral ovariectomies (OVX) or sham operations. Three weeks later, both first and second mandibular molars were extracted and the animals were killed by cervical dislocation 3, 5, or 7 days after tooth extraction. The granulation tissues were collected from the extracted alveolar sockets and used for zymographic, Western blot, or reverse transcription polymerase chain reaction (RT-PCR) analysis. There was a gradual increase on the expression of all studied proteins as well as MMP-2 and -9 activities in the periods after surgery. In contrast, OVX animals showed a significant decrease in the gelatinolytic activities and expression of MMP-2 and -9 and types I and III collagens. The results presented here in suggest that the absence of estrogen may possibly contribute to the delayed alveolar wound healing by interfering with the extracellular matrix turnover.