Therapeutic effect of ethyl acetate extract from Asparagus cochinchinensis on phthalic anhydride-induced skin inflammation

Anti-chitinase-3-like 1 antibody attenuated atopic dermatitis-like skin inflammation through inhibition of STAT3-dependent CXCL8 expression

BACKGROUND AND PURPOSE

Chitinase-3-like 1 (CHI3L1) causes skin inflammation in the progression of atopic dermatitis. We investigated if anti-CHI3L1 antibody could prevent the development of atopic dermatitis and its mechanisms of action.

EXPERIMENTAL APPROACH

The effect of CHI3L1 antibody on phthalic anhydride-induced atopic dermatitis animal model and in vitro reconstructed human skin (RHS) model were investigated. Expression and release of atopic dermatitis-related cytokines were determined using an enzyme-linked immunosorbent assay, and RT-qPCR, STAT3 and CXCL8 signalling were measured by western blotting.

KEY RESULTS

Anti-CHI3L1 antibody suppressed phthalic anhydride-induced epidermal thickening, clinical score, IgE level and infiltration of inflammatory cells, and reduced phthalic anhydride-induced inflammatory cytokines concentration. In addition, CHI3L1 antibody treatment inhibited the expression of STAT3 activity in phthalic anhydride-treated skin. It was also confirmed that CHI3L1 antibody treatment alleviated atopic dermatitis-related inflammation in the RHS model. The inhibitory effects of CHI3L1 antibody was similar or more effective compared with that of the IL-4 antibody. We further found that CHI3L1 is associated with CXCL8 by protein-association network analysis. siRNA of CHI3L1 blocked the mRNA levels of CHI3L1, IL-1β, IL-4, CXCL8, TSLP, and the expression of CHI3L1 and p-STAT, and the level of CXCL8, whereas recombinant level of CXCL8 was elevated. Moreover, siRNA of STAT3 reduced the mRNA level of these cytokines. CHI3L1 and p-STAT3 expression correlated with the reduced CXCL8 level in the RHS in vitro model.

CONCLUSION AND IMPLICATIONS

Our data demonstrated that CHI3L1 antibody could be a promising effective therapeutic drug for atopic dermatitis.

Oligosaccharides from Asparagus cochinchinensis for ameliorating LPS-induced acute lung injury in mice

Asparagi radix is an edible herb with medicinal properties and is now widely used in clinical applications for improving pulmonary inflammation. However, the lung-protective effect and the active constituents of Asparagi radix are yet to be elucidated. Herein, the potential pulmonary protective effect of the oligosaccharides of Asparagi radix was investigated. We firstly identified eighteen oligosaccharides with different degrees of polymerization from Asparagi radix using HPLC-QTOF MS. Oligosaccharides were analysed for 20 samples of Asparagi radix collected from various regions in China using HILIC-ELSD and were found to stably exist in this herb. In this study, we found that AROS significantly reduced NO production and effectively down-regulated the mRNA expression of IL-6, IL-1β and TNF-α in RAW 264.7 cells, thereby reducing the inflammatory response induced by LPS. AROS also inhibited LPS-stimulated intracellular ROS production. A murine model of lipopolysaccharide (LPS)-induced acute lung injury was used to evaluate the in vivo anti-inflammatory and lung protective efficacies of AROS. AROS ameliorated the damage to the pulmonary cellular architecture pathological injury and lung edema. AROS significantly decreased the levels of cytokines IL-6, TNF-α and IL-1β; the levels of MPO and MDA; and superoxide dismutase consumption in vivo. This effect of oligosaccharides can explain the traditional usage of Asparagus cochinchinensis as a tonic medicine for respiratory problems, and oligosaccharides from Asparagi radix used as a natural ingredient can play an important role in protecting lung injury.

Asparagus cochinchinensis: A review of its botany, traditional uses, phytochemistry, pharmacology, and applications

Asparagus cochinchinensis (Lour.) Merr. (A. cochinchinensis) is a traditional herbal medicine that is used to treat constipation, fever, pneumonia, stomachache, tracheitis, rhinitis, cataract, acne, urticaria. More than 90 compounds have been identified from different structural types in A. cochinchinensis, including steroidal saponins, C21-steroides, lignans, polysaccharides, amino acids, etc. These bioactive ingredients make A. cochinchinensis remarkable for its pharmacological effects on anti-asthma, anti-inflammatory, anti-oxidation, anti-tumor, improving Alzheimer’s disease, neuroprotection, gut health-promoting and so on. Moreover, A. cochinchinensis also plays an important role in food, health product, cosmetic, and other fields. This review focused on the research publications of A. cochinchinensis and aimed to summarize the advances in the botany, traditional uses, phytochemistry, pharmacology, and applications which will provide reference for the further studies and applications of A. cochinchinensis.

Asparagus cochinchinensis alleviates disturbances of lipid metabolism and gut microbiota in high-fat diet-induced obesity mice

Asparagus cochinchinensis is a valuable traditional Chinese medicine that has anti-inflammatory ability and effectively regulates the dysbiosis within the body. Obesity is usually characterized by chronic low-grade inflammation with aberrant gut microbiota. However, the role of Asparagus cochinchinensis against obesity remains unknown. Therefore, a high-fat diet (HFD)-induced obese mouse model with or without aqueous extract from Asparagus cochinchinensis root (ACE) treatment was established herein to determine whether ACE alleviated obesity and its involved mechanisms. Our results showed that ACE administration significantly decreased the weight gain and relieved dyslipidemia induced by HFD Treatment of ACE also improved glucose tolerance and insulin resistance in obese animal model, and remarkably decreased inflammation and lipogenesis in the liver and adipose. Moreover, administration of ACE significantly reshaped the gut microbiota of obese mice. These findings together suggest that ACE has beneficial effect against HFD-induced obesity and will provide valuable insights for the therapeutic potential of ACE against obesity and may aid in strategy-making for weight loss.

Using metabolomics to discover the immunomodulator activity of food plants

Many edible plants exhibit immunomodulator activities that have beneficial effects on human health. These activities include the ability to activate, multiply, or suppress elements of the immune response. Some of these plants promote health by strengthening host defences against different diseases. In this article, we provide a comprehensive review of the constituents of several edible plants, their immunomodulatory activity, and mechanism of actions for Carica papaya, Coffea sp, Asparagus cochinchinensis, Dioscorea alata, beans, mushrooms, herbs, spices, and several vegetables. The studies reported here are pre-clinical (in vitro and in vivo) and clinical studies (limited in number). The bioactive compounds responsible for the immunomodulator activity of these plants were yet to be identified. This is because the plant is naturally a complex mixture, whilst the immune system is also an intricate system involving many cells and cytokines/chemokines. Metabolomics is a key tool for conducting global profiling of metabolites in a complex system. Therefore, it offers the ability to identify the presence of compounds in plant extracts associated with their immunomodulation effects. Likewise, metabolomics can also be used to detect any changes to metabolites in the cell as a response to treatment. Therefore, affected metabolic pathways that lead to the activation of certain immune responses can be determined from one single experiment. However, we found in this review that the use of a metabolomics approach is not yet fully developed for an immunomodulator study of food plants. This is important for the direction of future research in this field because unlike medicinal plants, food plants are consumed on a regular basis in small amounts with more obvious effects on the immune system. Information about possible bioactive compounds, their interactions (synergism, antagonism), and how the human body responds to them should be studied in a more holistic way.

Inhibition of Chitinase-3-like-1 by K284-6111 Reduces Atopic Skin Inflammation via Repressing Lactoferrin

Chitinase-3-like-1 (CHI3L1) is known to induce inflammation in the progression of allergic diseases. Previous our studies revealed that 2-({3-[2-(1-cyclohexen-1-yl)ethyl]-6,7-dimethoxy-4-oxo-3,4-dihydro-2-quinazolinyl}sulfanyl)-N-(4-ethylphenyl)butanamide (K284-6111; K284), the CHI3L1 inhibiting compound, has the anti-inflammatory effect on neuroinflammation. In this study, we investigated that K284 treatment could inhibit the development of atopic dermatitis (AD). To identify the effect of K284, we used phthalic anhydride (5% PA)-induced AD animal model and in vitro reconstructed human skin model. We analyzed the expression of AD-related cytokine mediators and NF-κB signaling by Western blotting, ELISA and quantitative real-time PCR. Histological analysis showed that K284 treatment suppressed PA-induced epidermal thickening and infiltration of mast cells. K284 treatment also reduced PA-induced release of inflammatory cytokines. In addition, K284 treatment inhibited the expression of NF-κB activity in PA-treated skin tissues and TNF-α and IFN-γ-treated HaCaT cells. Protein-association network analysis indicated that CHI3L1 is associated with lactoferrin (LTF). LTF was elevated in PA-treated skin tissues and TNF-α and IFN-γ-induced HaCaT cells. However, this expression was reduced by K284 treatment. Knockdown of LTF decreased the expression of inflammatory cytokines in TNF-α and IFN-γ-induced HaCaT cells. Moreover, anti-LTF antibody treatment alleviated AD development in PA-induced AD model. Our data demonstrate that CHI3L1 targeting K284 reduces AD-like skin inflammation and K284 could be a promising therapeutic agent for AD by inhibition of LTF expression.

Anti-inflammatory effects of Capparis ecuadorica extract in phthalic-anhydride-induced atopic dermatitis of IL-4/Luc/CNS-1 transgenic mice

CONTEXT

The natural products derived from Capparis ecuadorica H.H. Iltis (Capparaceae) could have great potential for anti-inflammation since they inhibited the inflammatory response in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells.

OBJECT

This study investigated the anti-inflammatory effects and related mechanism of methanol extract of C. ecuadorica leaves (MCE) during atopic dermatitis (AD) responses.

MATERIALS AND METHODS

Alterations in the phenotypical markers for AD, luciferase signal, iNOS-mediated COX-2 induction pathway, and inflammasome activation were analysed in non-Tg (n = 5) and 15% phthalic anhydride (PA) treated IL-4/Luc/CNS-1 transgenic (Tg) HR1 mice (n = 5 per group), subsequent to treatment with acetone-olive oil (AOO), vehicle (DMSO) and two dose MCE (20 and 40 mg/kg) three times a week for 4 weeks.

RESULTS

MCE treatment reduced the intracellular ROS level (48.2%), NO concentration (7.1 mmol/L) and inflammatory cytokine expressions (39.1%) in the LPS-stimulated RAW264.7 cells. A significant decrease was detected for ear thickness (16.9%), weight of lymph node (0.7 mg), IgE concentration (1.9 µg/mL), and epidermal thickness (31.8%) of the PA + MCE treated Tg mice. MCE treatment induced the decrease of luciferase signal derived from the IL-4 promoter and the recovery of the IL-4 downstream regulator cytokines. PA + MCE treated Tg mice showed decreasing infiltration of mast cells (42.5%), iNOS-mediated COX-2 induction pathway, MAPK signalling pathway and inflammasome activation in the ear tissue.

CONCLUSIONS

These findings provide the first evidence that MCE may have great potential to suppress chemical-induced skin inflammation through the suppression of IL-4 cytokine and the iNOS-mediated COX-2 induction pathway, and activation of inflammasome.

Anti-inflammatory effect of astaxanthin in phthalic anhydride-induced atopic dermatitis animal model

In this study, we investigated anti-dermatitic effects of astaxanthin (AST) in phthalic anhydride (PA)-induced atopic dermatitis (AD) animal model as well as in vitro model. AD-like lesion was induced by the topical application of 5% PA to the dorsal skin or ear of Hos:HR-1 mouse. After AD induction, 100 μL of 1 mg/mL and 2 mg/mL of AST (10 μg or 20 μg/cm² ) was spread on the dorsum of ear or back skin three times a week for four weeks. We evaluated dermatitis severity, histopathological changes and changes in protein expression by Western blotting for inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and nuclear factor-κB (NF-κB) activity. We also measured tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and immunoglobulin E (IgE) concentration in the blood of AD mice by enzyme-linked immunosorbent assay (ELISA). AST treatment attenuated the development of PA-induced AD. Histological analysis showed that AST inhibited hyperkeratosis, mast cells and infiltration of inflammatory cells. AST treatment inhibited expression of iNOS and COX-2, and NF-κB activity as well as release of TNF-α, IL-1β, IL-6 and IgE. In addition, AST (5, 10 and 20 μM) potently inhibited lipopolysaccharide (LPS) (1 μg/mL)-induced nitric oxide (NO) production, expression of iNOS and COX-2 and NF-κB DNA binding activities in RAW 264.7 macrophage cells. Our data demonstrated that AST could be a promising agent for AD by inhibition of NF-κB signalling.

The Anti-Inflammatory Effects of Fermented Herbal Roots of Asparagus cochinchinensis in an Ovalbumin-Induced Asthma Model

Introduction: Roots of Asparagus cochinchinensis, which have pharmacologically active ingredients, have received great attention because they show good therapeutic effects for various inflammatory diseases without specific toxicity. This study investigated the anti-asthmatic effects of a butanol extract of Asparagus cochinchinensis roots that had been fermented with Weissella cibaria (BAW) and its possible underlying cholinergic regulation. Methods: Alterations of the anti-asthmatic markers and the molecular response factors were measured in an ovalbumin (OVA)-induced asthma model after treatment with BAW. Results: Treatment with BAW decreased the intracellular reactive oxygen species (ROS) production in lipopolysaccharides (LPS) activated RAW264.7 cells. The results of the animal experiments revealed lower infiltration of inflammatory cells and bronchial thickness, and a significant reduction in the number of macrophages and eosinophils, concentration of OVA-specific IgE, and expression of Th2 cytokines in the OVA + BAW treated group. In addition, a significant recovery of goblet cell hyperplasia, MMP-9 expression, and the VEGF signaling pathway was observed upon airway remodeling in the OVA + BAW treated group. Furthermore, these responses of BAW were linked to recovery of acetylcholine esterase (AChE) activity and muscarinic acetylcholine receptor (mAChR) M3 downstream signaling pathway in epithelial cells, smooth muscle cells, and afferent sensory nerves of OVA + BAW-treated mice. Conclusion: Overall, these findings are the first to provide evidence that the therapeutic effects of BAW can prevent airway inflammation and remodeling through the recovery of cholinergic regulation in structural cells and inflammatory cells of the chronic asthma model.

Dose dependence and durability of the therapeutic effects of Asparagus cochinchinensis fermented extract in an ovalbumin-challenged asthma model

The butanol extract of Asparagus cochinchinensis roots fermented with Weissella cibaria (BAfW) significantly suppressed the inflammatory response induced by lipopolysaccharide (LPS) treatment in RAW264.7 cells. To investigate the dose dependence and durability of BAfW on the anti-asthma effects, alterations in key parameters were measured in ovalbumin (OVA)-challenged Balb/c mice treated with the different doses of BAfW at three different time points. The number of immune cells, OVA-specific IgE level, thickness of respiratory epithelium and mucus score decreased significantly in a dose-dependent manner in response to treatment with 125 to 500 mg/kg BAfW (P<0.05), although the highest level was detected in the 500 mg/kg treated group. Moreover, the decrease in these parameters was maintained from 24 to 48 h in the 500 mg/kg of BAfW treated group. At 72 h, the effects of BAfW on the number of immune cells, OVA-specific IgE level and thickness of respiratory epithelium partially disappeared. Overall, this study provides the first evidence that the anti-asthma effect of BAfW may reach the maximum level in OVA-challenged Balb/c mice treated with 500 mg/kg and that these effects can last for 48 h.

Anti-inflammatory effect of Centella asiatica phytosome in a mouse model of phthalic anhydride-induced atopic dermatitis

BACKGROUND

Centella asiatica phytosome (CA phytosome) has potent antioxidant and anti-inflammatory properties. However, its anti-dermatitic effect has not yet been reported.

PURPOSE

We investigated the effects of CA phytosome on inflammatory reponses by macrophages in an atopic dermatitis (AD) mouse model.

STUDY DESIGN

The effects of CA phytosome on atopic dermatitis were examined by using phthalic anhydride (PA)-induced AD mouse model and RAW 264.7 murine macrophages.

METHODS

An AD-like lesion was induced by a topical application of 5% phthalic anhydride (PA) to the dorsal skin or ear of HR-1 mice. After AD induction, 100 µl (20 µl/cm²) of 0.2% and 0.4% CA phytosome was spread on the dorsal skin and ear of the mice three times a week for four weeks. We evaluated histopathological changes and changes in protein expression by Western blotting for iNOS and COX-2; NF-κB activity was determined by EMSA. We also measured TNF-α, IL-1β, and IgE concentration in the blood of AD mice by ELISA.

RESULTS

Histological analysis showed that CA phytosome inhibited infiltration of inflammatory cells. CA phytosome treatment inhibited the expression of iNOS and COX-2, activity of NF-κB, and release of TNF-α, IL-1β, and IgE. In addition, CA phytosome (5, 10, and 20 µg/ml) potently inhibited LPS (1 µg/ml)-induced NO production as well as iNOS and COX-2 expression in RAW 264.7 macrophage. Furthermore, CA phytosome inhibited LPS-induced DNA binding activities of NF-κB, and this was associated with the discontinuation of IκBα degradation and subsequent decreases in the translocation of p65 and p50 into the nucleus.

CONCLUSION

From our data, CA phytosome application, which operates via NF-κB signaling inhibition, seems to be a promising AD treatment. Herein, we investigated the effects of Centella asiatica phytosome (CA phytosome) on inflammatory responses by macrophages in an atopic dermatitis (AD) mouse model. An AD-like lesion was induced by the topical application of 5% phthalic anhydride (PA) to the dorsal skin or ear of HR-1 mice. After AD induction, 100 µl (20 µl/cm²) of 0.2% and 0.4% CA phytosome was spread on the dorsal skin and ear of the mice three times a week for four weeks. We evaluated dermatitis severity, histopathological changes, and changes in protein expression by Western blotting for iNOS and COX-2; NF-κB activity was determined by gel electromobility shift assay (EMSA). We also measured TNF-α, IL-1β, and IgE concentration in the blood of AD mice by enzyme-linked immunosorbent assay (ELISA). CA phytosome attenuated the development of PA-induced AD. Histological analysis showed that CA phytosome inhibited hyperkeratosis, proliferation of mast cells, and infiltration of inflammatory cells. Furthermore, CA phytosome treatment inhibited the expression of iNOS and COX-2, activity of NF-κB, and release of TNF-α, IL-1β, and IgE. In addition, CA phytosome (5, 10, and 20 µg/ml) potently inhibited lipopolysaccharide (LPS) (1 µg/ml)-induced NO production as well as iNOS and COX-2 expression in RAW 264.7 macrophage cells. Furthermore, CA phytosome inhibited LPS-induced DNA binding activities of NF-κB, and this was associated with the discontinuation of IκBα degradation and subsequent decreases in the translocation of p65 and p50 into the nucleus. From our data, CA phytosome application, which operates via NF-κB signaling inhibition, seems to be a promising AD treatment.

Saponin-enriched extract of Asparagus cochinchinensis alleviates airway inflammation and remodeling in ovalbumin-induced asthma model

Asthma is a chronic inflammatory disease characterized by T-lymphocyte and eosinophil infiltration, mucus overproduction and airway hyper-responsiveness. The present study examined the therapeutic effects and action mechanism of a saponin-enriched extract of Asparagus cochinchinensis (SEAC) on airway inflammation and remodeling in an ovalbumin (OVA)-induced asthma model. To accomplish this, alterations of the nitric oxide (NO) level, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression levels, as well as variations in immune cell numbers, immunoglobulin E (IgE) concentration, histopathological structure and inflammatory cytokine levels were measured in lipopolysaccharide (LPS)-activated RAW264.7 cells or an OVA-induced mouse model of asthma treated with SEAC. The concentration of NO and mRNA levels of COX-2 and iNOS were significantly decreased in the SEAC + LPS-treated RAW264.7 cells compared with the vehicle + LPS-treated RAW264.7 cells. Additionally, in the OVA-induced asthma model, the number of immune cells in the bronchoalveolar lavage fluid, the concentration of OVA-specific IgE, the infiltration of inflammatory cells, the bronchial thickness and the levels of the inflammatory mediators interleukin-4 (IL-4), IL-13 and COX-2 were significantly lower in the OVA + SEAC-treated group compared with the OVA + vehicle-treated group. In addition, a significant reduction in goblet cell hyperplasia, peribronchiolar collagen layer thickness and VEGF expression for airway remodeling was detected in the OVA + SEAC-treated group compared with the OVA + vehicle-treated group. These findings indicate that SEAC is a suppressor of airway inflammation and remodeling, and may therefore be useful as an anti-inflammatory drug for the treatment of asthma.

Hepatotoxicity and nephrotoxicity of saponin-enriched extract of Asparagus cochinchinensis in ICR mice

The inhibitory effects of Asparagus cochinchinensis against inflammatory response induced by lipopolysaccharide (LPS), substance P and phthalic anhydride (PA) treatment were recently reported for some cell lines and animal models. To evaluate the hepatotoxicity and nephrotoxicity of A. cochinchinensis toward the livers and kidneys of ICR mice, alterations in related markers including body weight, organ weight, urine composition, liver pathology and kidney pathology were analyzed in male and female ICR mice after oral administration of 150, 300 and 600 mg/kg body weight/day saponin-enriched extract of A. cochinchinensis (SEAC) for 14 days. The saponin, total flavonoid and total phenol levels were found to be 57.2, 88.5 and 102.1 mg/g in SEAC, respectively, and the scavenging activity of SEAC gradually increased in a dose-dependent manner. Moreover, body and organ weight, clinical phenotypes, urine parameters and mice mortality did not differ between the vehicle and SEAC treated group. Furthermore, no significant alterations were measured in alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), blood urea nitrogen (BUN) and the serum creatinine (Cr) in the SEAC treated group relative to the vehicle treated group. Moreover, the specific pathological features induced by most toxic compounds were not observed upon liver and kidney histological analysis. Overall, the results of the present study suggest that SEAC does not induce any specific toxicity in the livers and kidneys of male and female ICR mice at doses of 600 mg/kg body weight/day.

Anti-Inflammatory Effect of Titrated Extract of Centella asiatica in Phthalic Anhydride-Induced Allergic Dermatitis Animal Model

Centella asiatica has potent antioxidant and anti-inflammatory properties. However, its anti-dermatitic effect has not yet been reported. In this study, we investigated the anti-dermatitic effects of titrated extract of Centella asiatica (TECA) in a phthalic anhydride (PA)-induced atopic dermatitis (AD) animal model as well as in vitro model. An AD-like lesion was induced by the topical application of five percent PA to the dorsal skin or ear of Hos:HR-1 mouse. After AD induction, 100 μL of 0.2% and 0.4% of TECA (40 μg or 80 μg/cm²) was spread on the dorsum of the ear or back skin three times a week for four weeks. We evaluated dermatitis severity, histopathological changes and changes in protein expression by Western blotting for inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and NF-κB activity, which were determined by electromobility shift assay (EMSA). We also measured TNF-α, IL-1β, IL-6, and IgE concentration in the blood of AD mice by enzyme-linked immunosorbent assay (ELISA). TECA treatment attenuated the development of PA-induced atopic dermatitis. Histological analysis showed that TECA inhibited hyperkeratosis, mast cells and infiltration of inflammatory cells. TECA treatment inhibited expression of iNOS and COX-2, and NF-κB activity as well as the release of TNF-α, IL-1β, IL-6, and IgE. In addition, TECA (1, 2, 5 μg/mL) potently inhibited Lipopolysaccharide (LPS) (1 μg/mL)-induced NO production, expression of iNOS and COX-2, and NF-κB DNA binding activities in RAW264.7 macrophage cells. Our data demonstrated that TECA could be a promising agent for AD by inhibition of NF-κB signaling.

In vivo study on the biocompatibility of chitosan-hydroxyapatite film depending on degree of deacetylation

Chitosan, produced from chitin, is one of the polymers with promising applications in various fields. However, despite diverse research studies conducted on its biocompatibility, its uses are still limited. The main reason is the degree of deacetylation (DOD), which represents the proportion of deacetylated units in the polymer and is directly correlated with its biocompatibility property. In this article, the in vivo biocompatibility of three chitosan-hydroxyapatite composite films composed of chitosan with different DOD values was investigated by traditional biological protocols and novel optical spectroscopic analyses. The DOD of the chitosan obtained from three different manufacturers was estimated and calculated by Raman spectroscopy, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance spectroscopy. The chitosan with the higher DOD induced a higher incidence of inflammation in skin cells. The amino group density, biodegradability, and crystallinity of chitosan are the three possible factors that need to be considered when determining the biocompatibility of the films for in vivo application, as they led to complicated biological results, resulting in either better or worse inflammation even when using chitosan products with the same DOD. This basic study on the relationship between the DOD and inflammation is valuable for the development of further chitosan-based researches. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1637-1645, 2017.