The effect of azelastine on acute radiation dermatitis in mice models

Induction of Radiodermatitis in Nude Mouse Model using Gamma Irradiator IBL 637

Introduction

Acute radiodermatitis is a common, though severe, side effect of radiotherapy against cancer that may lead to an interruption or even abortion of the radiotherapy. Mouse models provide an excellent tool to study pathomechanisms of a radiation-induced dermatitis as well as to test and develop novel innovative treatment strategies.

Objective

The aim of this study was to provide an overview of different mouse models and irradiation devices that have been used so far and to describe the process of the induction of a radiation dermatitis in an immune proficient nude mouse model (SKH1-Hr^hr) using a IBL 637 cesium-137γ-ray machine.

Methods

This process includes the construction of a radiation shielding chamber, restricting the radiation to the right hind leg of the mouse, a dosimetry, and a dose finding study to identify the appropriate irradiation dose to induce a moderate radiation dermatitis.

Results

A radiation shielding chamber was successfully constructed allowing selective irradiation of the right hind leg. A moderate radiodermatitis is induced with irradiation doses in the range of 60–70 Gy under the here described conditions. Symptoms peak about 8 days after irradiation and decrease relatively quickly thereafter. Histological analyses confirmed typical signs of inflammation.

Conclusion

This study describes for the first time a protocol to induce a moderate radiodermatitis in the nude mouse model SKH1-Hr^hr using a IBL 637 gamma irradiator. This protocol will allow researchers to study novel treatment strategies to alleviate the burden of a radiodermatitis as a side effect of cancer treatment.

Use of H-1 Antihistamine in Dermatology: More than Itch and Urticaria Control: A Systematic Review

H-1 antihistamines are commonly used in dermatological practice for itch and urticaria control. The widespread expression of H-1 receptor on different cells in the skin and various biologic functions of H-1 antihistamines indicate the possible treatment potentials of H-1 antihistamines in dermatology. A literature search was performed on PubMed and Embase, targeting articles reporting use of antihistamine for purposes other than itch and urticaria control in dermatological practice. Several off-label usages of antihistamines were identified, including alopecia, acne, Darier disease, eosinophilic dermatoses, paraneoplastic dermatoses, psoriasis, lichen nitidus, radiation dermatitis, skin dysesthesia, and cutaneous malignancies. Additional benefits were observed when H-1 antihistamines were used either alone or in combination with other therapeutic modalities. Although various novel uses of H-1 antihistamines have been uncovered, the evidence level of most included studies is weak. Further randomized control trials are warranted to better evaluate the efficacy and dosage of H-1 antihistamine for dermatological disorders.

Biochemical and Histopathological Evaluation of the Radioprotective Effects of Melatonin Against Gamma Ray-Induced Skin Damage

BACKGROUND

Radiotherapy is one of the treatment methods for cancers using ionizing radiations. About 70% of cancer patients undergo radiotherapy. Radiation effect on the skin is one of the main complications of radiotherapy and dose limiting factor. To ameliorate this complication, we used melatonin as a radioprotective agent due to its antioxidant and anti-inflammatory effects, free radical scavenging, improving overall survival after irradiation as well as minimizing the degree of DNA damage and frequency of chromosomal abrasions.

METHODS

Sixty male Wistar rats were randomly assigned to 4 groups: control (C), melatonin (M), radiation (R) and melatonin + radiation (MR). A single dose of 30 Gy gamma radiation was exposed to the right hind legs of the rats while 40 mg/ml of melatonin was administered 30 minutes before irradiation and 2 mg/ml once daily in the afternoon for one month till the date of rat's sacrifice. Five rats from each group were sacrificed 4, 12 and 20 weeks after irradiation. Afterwards, their exposed skin tissues were examined histologically and biochemically.

RESULTS

In biochemical analysis, we found that malondialdehyde (MDA) levels significantly increased in R group and decreased significantly in M and MR groups after 4, 12, and 20 weeks, whereas catalase (CAT) and superoxide dismutase (SOD) activities decreased in the R group and increased in M and MR groups during the same time periods compared with the C group (p<0.05). Histopathological examination found there were statistically significant differences between R group compared with the C and M groups for the three different time periods (p<0.005, p<0.004 and p<0.004) respectively, while R group differed significantly with MR group (p<0.013). No significant differences were observed between C and M compared with MR group (p>0.05) at 4 and 20 weeks except for inflammation and hair follicle atrophy, while there were significant effects at 12 weeks (p<0.05).

CONCLUSION

Melatonin can be successfully used for the prevention and treatment of radiation-induced skin injury. We recommend the use of melatonin in optimal and safe doses. These doses should be administered over a long period of time for effective radioprotection and amelioration of skin damages as well as improving the therapeutic ratio of radiotherapy.

Zinc Sulfate and/or Growth Hormone Administration for the Prevention of Radiation-Induced Dermatitis: a Placebo-Controlled Rat Model Study

Growth hormone (GH) and zinc (Zn) were evaluated for their potential to prevent radiation injury using a rat model of radiation-induced skin injury. Sprague-Dawley rats were divided into five groups: a control group not receiving Zn, GH, or irradiation: a radiation (RT) group receiving a single 30 Gy dose of gamma irradiation to the right hind legs; a radiation + GH group (RT + GH) receiving a single 30 Gy dose of gamma irradiation plus the subcutaneous administration of 0.01 IU kg d^-1 GH; a radiation + Zn group (RT + Zn) receiving a single 30 Gy dose plus 5 mg kg d^-1 Zn po; and a radiation + GH + Zn group (RT + GH + Zn) group receiving a single 30 Gy dose plus subcutaneous 0.01 IU kg d^-1 GH and 5 mg kg d^-1 Zn po. Acute skin reactions were assessed every 3 days by two radiation oncologists grouping. Light microscopic findings were assessed blindly by two pathologists. Groups receiving irradiation were associated with dermatitis as compared to the control group (P < 0.05). The severity of radiodermatitis in the RT + GH, RT + Zn, and RT + GH + Zn groups was significantly lower than that in the RT group (P < 0.05). Furthermore, radiodermatitis was observed earlier in the RT group than in the other treatment groups (P < 0.05). GH and Zn effectively prevented epidermal atrophy, dermal degeneration, and hair follicle atrophy. The highest level of protection against radiation dermatitis was observed in the combination group.

Mechanisms of cellular fibrosis associated with cancer regimen-related toxicities

Fibrosis is a common, persistent and potentially debilitating complication of chemotherapy and radiation regimens used for the treatment of cancer. The molecular mechanisms underlying fibrosis have been well studied and reveal overall processes that are largely ubiquitous. However, it is important to note that although the processes are similar, they result in cellular phenotypes that are highly tissue specific. These tissue specific differences may present opportunities for therapeutic interventions to prevent or treat this often irreversible condition. Data generated from animal models of cancer therapy-related tissue toxicities have revealed that the signaling pathways involved in fibrosis are the same as those involved in the normal injury response and include the transforming growth factor β superfamily and a range of pro-inflammatory cytokines. The critical difference between normal wound healing and fibrosis development appears to be, that in fibrosis, these signaling pathways escape normal cellular regulation. As a result, an injury state is maintained and processes involved in normal healing are usurped. There are a few, if any, therapeutics that effectively prevent or treat fibrosis in patients. Consequently, cancer survivors may be chronically plagued with a variety of life-altering fibrosis-related symptoms. Uncovering the signaling pathways that drive cellular fibrosis is paramount to the development of specific therapeutics that will mitigate this potentially devastating condition.

Early diagnosis of radiodermatitis using lactate dehydrogenase isozymes in hairless mice (SKH1-hr)

In this study, we evaluate a method for the early diagnosis of radiodermatitis for use in the prevention and therapy of this condition. Hairless mice (SKH1-hr) were used to study the early diagnosis of radiodermatitis. Lactate dehydrogenase (LDH, EC 1.1.1.27) isozymes were analyzed using native-polyacrylamide gel electrophoresis and western blotting of blood serum and tissues collected from SKH1-hr mice. Radiodermatitis developed 24 days after the first X-irradiation. Reduced spleen weight was observed after the last X-irradiation (P<0.05). Thereafter the weight increased until 24 days after the first irradiation, finally reaching levels comparable to those in the sham-irradiated control group. LDH activity was the highest in skeletal muscle and lowest in blood serum. LDH C₄, A₄, A₃B, A₂B₂, AB₃, and B₄ isozymes were detected, in the mentioned order, from the cathode. This result was similar in other mouse strains. In the irradiated group, LDH A₄ isozyme levels were reduced in the serum until inflammation occurred, whereas those of B₄ isozyme were elevated. The subunits A and B followed a similar trend to that of LDH A₄ and B₄ isozyme, respectively. Importantly, antibodies against LDH B₄ isozyme could prove useful in the early diagnosis of radiodermatitis.

New model of radiation-induced skin ulcer in rats

Our aim was to provide a new animal model for intractable skin ulcers in irradiated rats. Twenty-four rats were irradiated with total single radiographic irradiation doses of 10, 15, 20, and 30 Gy. The skin was observed for 6 months. In the 10-Gy group, there were no visible changes to the skin. In the 15-Gy group, epilation and depigmentation were seen about 2 weeks after irradiation. In the groups over 20-Gy, minor erosion or skin ulcers appeared in most rats. The wounds healed in the 20-Gy group, but many in the 30-Gy group could not be healed. A further 36 rats were irradiated with 20 Gy, and this was followed by the creation of cutaneous full-thickness defects at different periods. The size of the wounds was measured on days 0, 3, 5, 7, 10, and 14. Delayed wound healing was found in the irradiated groups compared with the unirradiated group (p = 0.01). There were no differences in the time of ulceration, except in the Day 7 group (p = 0.03).

The protective effects of Ginkgo biloba extract (EGb-761) on radiation-induced dermatitis: an experimental study

BACKGROUND

Irradiation of the skin induces production of free radicals, resulting in oxidative stress. EGb-761, an extract from the leaves of the Ginkgo biloba tree, has been reported to be an effective exogenous antioxidant based on its free-radical scavenger properties.

AIM

To investigate the protective effect of G. biloba extract (EGb-761) on radiation-induced dermatitis in rats.

METHODS

Forty male Wistar rats were divided equally into four groups: group 1 received sham radiotherapy (RT) without EGb-761, group 2 received sham RT with EGb-761, group 3 received RT without EGb-761, and group 4 received RT with EGb-761. Levels of malondialdehyde (MDA), nitric oxide (NOx) and glutathione (GSH) were measured. Dermatitis was assessed with a semiquantitative dermatitis item score. The intensity of staining and diffusion of expression for proliferating cellular nuclear antigen (PCNA) and transforming growth factor (TGF)-β3 were also evaluated.

RESULTS

The enhanced oxidative stress seen after RT was markedly diminished when EGb-761 was administered with RT; significantly lower mean MDA (P < 0.005) and higher mean GSH (P < 0.001) levels were seen in group 4 compared with group 3. Although there was a decrease in NOx levels, this was not significant. All (100%) of the animals in group 3 developed dermatitis, whereas only 13% of the animals in group 4 did so (P < 0.0001). There was a significant difference between group 1 and group 3 in PCNA and TGF-β3 staining (P < 0.05), whereas no difference was seen between groups 3 and 4; however, the intensity of staining and diffusion of expression were lower in group 4 than in group 3.

CONCLUSIONS

Prophylactic administration of EGb-761 seems to have a protective effect against radiation-induced dermatitis.

Irradiation of normal mouse tissue increases the invasiveness of mammary cancer cells

PURPOSE

Treatment of breast tumours frequently involves irradiating the whole breast to reach malignant microfoci scattered throughout the breast. In this study, we determined whether irradiation of normal tissues could increase the invasiveness of breast cancer cells in a mouse model.

MATERIALS AND METHODS

Non-irradiated MC7-L1 mouse mammary carcinoma cells were injected subcutaneously in irradiated and non-irradiated thighs of Balb/c mice. The invasion volume, tumour volume, blood vessel permeability and interstitial volumes were monitored by magnetic resonance imaging (MRI). Slices of normal tissue invaded by cancer cells were examined by histology. Activity of matrix metalloproteinase -2 and -9 (MMP -2 and -9) in healthy and irradiated tissues was determined, and the proliferation index of the invading cancer cells was evaluated.

RESULTS

Three weeks after irradiation, enhancement of MC7-L1 cells invasiveness in irradiated thighs was already detected by MRI. The tumour invasion volume continued to extend 28- to 37-fold compared to the non-irradiated implantation site for the following three weeks, and it was associated with an increase of MMP-2 and -9 activities in healthy tissues. The interstitial volume associated with invading cancer cells was significantly larger in the pre-irradiated sites; while the blood vessels permeability was not altered. Cancer cells invading the healthy tissues were proliferating at a lower rate compared to non-invading cancer cells.

CONCLUSION

Implantation of non-irradiated mammary cancer cells in previously irradiated normal tissue enhances the invasive capacity of the mammary cancer cells and is associated with an increased activity of MMP-2 and -9 in the irradiated normal tissue.

The preventive effect of recombinant human growth factor (rhEGF) on the recurrence of radiodermatitis

The effects of topical application of recombinant human epidermal growth factor (rhEGF) on wound healing and the recurrence of radiodermatitis were assessed in the irradiated skin of BALB/c Nu/Nu mice. Mice irradiated with 45 Gy of radiation were divided into 5 groups and treated with 10, 50, and 100 µg/g rhEGF ointment, vehicle alone, or no treatment (control) for 6 months. Wounds were observed initially in all groups and complete healing time (HT(100)) for initial wound repair did not differ significantly among groups. However, the rate of recurrence over 6 months was significantly lower in the EGF-treated groups than in the control group (p < 0.05). Histological examination showed that treatment with the optimum dose of EGF (50 µg/g) accelerated normal wound healing when compared with the higher dose of EGF (100 µg/g), vehicle alone, or no treatment, with the latter group showing irregular epidermal thickness, poor definition of epidermis and dermis, and unstable dermal structure. Collagen distribution was also significantly increased in mice treated with 50 µg/g rhEGF (p < 0.05) compared with the control or vehicle-treated group. Taken together, these results indicate that treatment with exogenous EGF (50 µg/g dose) can enhance radiation-induced wound repair while preserving structural tissue stability and preventing the recurrence of radiodermatitis.

Allopurinol gel mitigates radiation-induced mucositis and dermatitis

It has not been verified whether allopurinol application is beneficial in decreasing the severity of radiation-induced oral mucositis and dermatitis. Rats were divided into 4 groups and received 15 Gy irradiation on the left whisker pad. Group 1 received only irradiation. Group 2 was maintained by applying allopurinol/carrageenan-mixed gel (allopurinol gel) continuously from 2 days before to 20 days after irradiation. Group 3 had allopurinol gel applied for 20 days after radiation. Group 4 was maintained by applying carrageenan gel continuously from 2 days before to 20 days after irradiation. The intra oral mucosal and acute skin reactions were assessed daily using mucositis and skin score systems. The escape thresholds for mechanical stimulation to the left whisker pad were measured daily. In addition, the irradiated tissues at the endpoint of this study were compared with naïve tissue. Escape threshold in group 2 was significantly higher than that in group 1, and mucositis and skin scores were much improved compared with those of group 1. Concerning escape threshold, mucositis and skin scores in group 3 began to improve 10 days after irradiation. Group 4 showed severe symptoms of mucositis and dermatitis to the same extent as that observed in group 1. In the histophathological study, the tissues of group 1 showed severe inflammatory reactions, compared with those of group 2. These results suggest that allopurinol gel application can mitigate inflammation reactions associated with radiation-induced oral mucositis and dermatitis.

Involvement of histamine released from mast cells in acute radiation dermatitis in mice

A possible involvement of histamine in acute radiation dermatitis in mice was investigated. The dose of 40 Gy of gamma irradiation induced erythema and edema in C57BL/6 mice treated with vehicle. However, in C57BL/6 mice treated with chlorpheniramine and WBB6F1-W/Wv mice, erythema and edema were not observed. In all of these mice, epilation and dry desquamation were induced, but bepotastine significantly reduced the extent of these areas. These results suggest that gamma irradiation-induced erythema and edema were caused by histamine released from mast cells via histamine H1 receptor, and epilation was induced by other inflammatory mediators.

Prevention and Treatment of Acute Radiation Dermatitis: A Literature Review

PURPOSE/OBJECTIVES

To review historical and current research data on prevention and treatment of acute radiation dermatitis.

DATA SOURCES

18 research trials and 1 case report published from 1967-2001 and 1 unpublished research trial from 1972.

DATA SYNTHESIS

Washing the skin with mild soap and water and the hair with mild shampoo is safe during radiation therapy. Biafine (Medix Pharmaceuticals, Inc., Largo, FL), chamomile cream, almond ointment, topical vitamin C, and gentian violet have not been proven effective and should not be used. Transparent, hydrocolloid, and hydrogel dressings have been beneficial, as have sucralfate cream and corticosteroid cream. Aloe vera may be beneficial and is not harmful.

CONCLUSIONS

The existing scientific data are lacking in quantity and quality. The current body of evidence is unable to provide clinicians with comprehensive guidelines for prevention and management of acute radiation dermatitis.

IMPLICATIONS FOR NURSING

Nurse clinicians and nurse scientists must partner to conduct further research to add to the limited resources about the prevention and management of acute radiation dermatitis and develop comprehensive evidence-based clinical practice guidelines.

Is growth hormone a radioprotective agent?

There is currently substantial clinical interest in growth hormone (GH) as a protective agent against radiation-related normal tissue injury. To further assess the potential radiation injury-preventive effects of GH, these effects were studied in rats by using a radiation-induced skin injury model. Group 1 received neither GH nor irradiation (control group). Group 2 received 30 Gy of gamma irradiation as a single dose to the right hind legs of the rats (radiation group). Group 3 and 4 received the same irradiation plus either 0.01 U/kg/day GH (RT + 0.01 GH group) or 0.02 U/kg/day GH (RT + 0.02 GH group) subcutaneously. Clinically and histopathologically, acute skin reactions were assessed by two independent experts in radiation oncology and pathology, respectively. Irradiation increased dermatitis in rats when compared with the control group. The severity of radiodermatitis in the rats in the RT + 0.01 GH and RT + 0.02 GH groups was significantly lower than that in the RT group; radiodermatitis developed earlier in the RT group than in the other groups. GH was efficacious in preventing epidermal atrophy, dermal degeneration such as oedema and collagen fibre loss, and hair follicle atrophy, but not better than in the control group. These results are preliminary to studies that will be performed with higher doses of GH in radiation-treated cancer patients, with the aim of reducing radiation-induced toxicity.

Altered immune cell proportions in the radiodermatitis induced hairless mice-1 (HR-1)

Accidental radiation exposures or radiation therapy can cause internal and external damage including radiodermatitis. Even though radiodermatitis is one of the dose limiting factors in radiotherapy, the immunological nature of it is not yet been clearly understood. In this study, we have examined the alteration in immune cell population during the radiodermatitis process. A radiodermatitis model was established in HR-1 mice by locally exposing a posterior dorsal region to 10 Gy X-ray/day for 4 consecutive days. Collagen accumulation, redness, erythema, and dry desquamation of the skin were detected after X-irradiation. The size and total cell number of the spleen decreased immediately after X-irradiation, compared to those of the sham-irradiated mice, and recovered to the normal levels two weeks later. Reduction and recovery of the bone marrow cell population preceded a similar change of the spleen cell population. The proportion of CD4+ T cell increased, while the proportion of CD8+ T cell decreased ahead of the obvious skin damage, in both lymph node and spleen of the irradiated mice. Interestingly, the proportion of splenic monocytes/macrophages was expanded gradually at a similar kinetics with the aggravation of the radiodermatitis. The infiltration of the CD11b+ monocyte/macrophage to the X-irradiated skin also coincided with the development of radiodermatitis. These altered proportions of immune cells may play important roles in radiodermatitis.

Novel approaches to radiotherapy-induced skin reactions: A literature review

Patients undergoing radiotherapy treatment will receive some degree of skin damage. Internationally there are many preventative and treatment options recommended, with varying degrees of evidence of success. This review explores the possible benefits of various plant-based treatments within the context of other novel treatments. The evidence suggests that using a hydrophilic substance such as Aloe vera gel or vegetable oil that is high in essential fatty acids, is as effective as mild steroid creams such as 1% hydrocortisone in reducing the severity of reactions. Additionally with plant-based treatments there does not appear to be side effects such as may occur with steroids. There remains great scope for further studies either replicating some of these current studies or exploring other options such as the use of essential oils or other herbal extracts.

The effect of zinc sulphate in the prevention of radiation-induced dermatitis

There is currently substantial clinical interest in zinc (Zn) as a protective agent against radiation-related normal tissue injury. To further assess this drug's potential, the effect of Zn was studied in rats using a radiation-induced skin injury model. Sprague-Dawley rats were divided into four groups. Group 1 received neither Zn nor irradiation (control group). Group 2 received 30 Gy of gamma irradiation as a single dose to the right hind legs of the rats (RT Group). Groups 3 and 4 received the same irradiation plus 5 mg/kg/day Zn (RT+5 Zn group) or 10 mg/kg/day Zn orally (RT+10 Zn group), respectively. The rats were irradiated using a cobalt-60 teletherapy unit. Acute skin reactions were assessed every three days by two independent radiation oncology experts. At the endpoint of the study, light-microscopic findings were assessed by two independent expert pathology physicians. Clinically and histopathologically, irradiation increased dermatitis when compared with the control group (p < 0.05). The severity of radiodermatitis of the rats in the RT+5 Zn and RT+10 Zn groups was significantly lower than in the RT group (p < 0.05); radiodermatitis was seen earlier in the RT group than in the other groups (p < 0.05). Zn was found to be efficacious in preventing epidermal atrophy, dermal degeneration such as edema and collagen fiber loss, and hair follicle atrophy. The most protection for radiation dermatitis was observed in the RT+10 Zn group. It would be worthwhile studying the effects of zinc sulphate supplements in radiation-treated cancer patients, in the hope of reducing radiation-induced toxicity.