Iron overload induced submandibular glands toxicity in gamma irradiated rats with possible mitigation by hesperidin and rutin.

BACKGROUND: Radiation triggers salivary gland damage and excess iron accumulates in tissues induces cell injury. Flavonoids are found in some fruits and are utilized as potent antioxidants and radioprotective agents. This study aimed to evaluate the antioxidant and anti-inflammatory effects of hesperidin and rutin on gamma radiation and iron overload induced submandibular gland (SMG) damage and to evaluate their possible impact on mitigating the alteration in mTOR signaling pathway and angiogenesis. METHODS: Forty-eight adult male Wistar albino rats were randomly assigned to six groups: group C received a standard diet and distilled water; group H received hesperidin at a dose of 100 mg/kg; four times a week for four weeks; group U received rutin at a dose of 50 mg/kg; three times a week for three weeks; group RF received a single dose (5 Gy) of gamma radiation followed by iron at a dose of 100 mg/kg; five times a week for four weeks; group RFH received radiation and iron as group RF and hesperidin as group H; group RFU received radiation and iron as group RF and rutin as group U. SMG specimens from all groups were removed at the end of the experiment; and some were used for biochemical analysis, while others were fixed for histological and immunohistochemical examination. RESULTS: In the RF group, several genes related to antioxidants (Nrf-2 and SOD) and DNA damage (BRCA1) were significantly downregulated, while several genes related to inflammation and angiogenesis (TNFα, IL-1ß and VEGF) and the mTOR signaling pathway (PIK3ca, AKT and mTOR) were significantly upregulated. Acinar cytoplasmic vacuolation, nuclear pyknosis, and interacinar hemorrhage with distinct interacinar spaces were observed as histopathological changes in SMGs. The duct system suffered significant damage, eventually degenerating entirely as the cells were shed into the lumina. VEGF and NF-κB were also significantly overexpressed. Hesperidin and rutin cotreatment generated partial recovery as indicated by significant upregulation of Nrf-2, SOD and BRCA1 and considerable downregulation of TNF-α, IL-1ß, VEGF, PIK3ca, AKT, and mTOR. Although some acini and ducts continued to deteriorate, most of them had a normal appearance. There was a notable decrease in the expression of VEGF and NF-κB. CONCLUSIONS: In γ-irradiated rats with iron overload, the administration of hesperidin and rutin may mitigate salivary gland damage.

Comparative study between laser and conventional techniques for class V cavity preparation in gamma-irradiated teeth (in vitro study).

OBJECTIVE: The purpose of this study was to compare laser with conventional techniques in class V cavity preparation in gamma-irradiated teeth. METHODS: Forty extracted human teeth with no carious lesions were used for this study and were divided into two main groups: Group I (n = 20) was not subjected to gamma radiation (control) and Group II (n=20) was subjected to gamma radiation of 60 Gray. Standard class V preparation was performed in buccal and lingual sides of each tooth in both groups. Buccal surfaces were prepared by the Er,Cr:YSGG laser (Waterlase iPlus) 2780 nm, using the gold handpiece with MZ10 Tip in non-contact and the "H" mode, following parameters of cavity preparation - power 6 W, frequency 50 Hz, 90% water and 70% air, then shifting to surface treatment laser parameters - power 4.5 W, frequency 50 Hz, 80% water and 50% air. Lingual surfaces were prepared by the conventional high-speed turbine using round diamond bur. Teeth were then sectioned mesio-distally, resulting in 80 specimens: 40 of which were buccal laser-treated (20 control and 20 gamma-irradiated specimens) and 40 were lingual conventional high-speed bur specimens (20 control and 20 gamma-irradiated specimens). RESULTS: Microleakage analysis revealed higher scores in both gamma groups compared with control groups. Chi-square test revealed no significant difference between both control groups and gamma groups (p=1, 0.819, respectively). A significant difference was revealed between all 4 groups (p=0.00018). CONCLUSION: Both laser and conventional high-speed turbine bur show good bond strength in control (non-gamma) group, while microleakage is evident in gamma group, indicating that gamma radiation had a dramatic negative effect on the bond strength in both laser and bur-treated teeth.

Assessment of the effect of low-energy diode laser irradiation on gamma irradiated rats' mandibles.

OBJECTIVE: The purpose of the present study was to evaluate the biostimulative and regenerative effects of low intensity laser irradiation (LILT) (applied before or after initiation of radiotherapy) on gamma irradiated rats' jaw bones. METHODS: Forty eight male Albino rats were equally divided into two groups: group 1, in which the left side of the mandible was subjected to three successive sessions of laser (LILT) prior to whole body gamma radiation (2Gy/3 fractions/week) and group 2, received whole body gamma radiation (2Gy/3 fractions/week) prior to three successive sessions of laser applied to left side. The right side of both groups was used as gamma irradiated non-lased control group. Each group was then subdivided into four equal subgroups (a, b, c, d) according to the time of scarification (3, 7, 14, 21 days respectively). Specimens were subjected to histological, histomorphometric and scanning electron microscopic examinations. RESULTS: Thin irregular bone trabeculae and widened marrow spaces were identified in the control group. The lased sides of groups 1 and 2 demonstrated regular, thick and continuous bone trabeculae. Ultrastructurally, collagen fibres of the control group appeared irregularly arranged and more spaced compared to groups 1 and 2. Normal-sized osteocytic lacunae were seen in the lased groups, as compared to the wide lacunar spaces noted in the control group. Histomorphometric analysis showed a significant increase in the area of bone trabeculae, as well as the width of compact bone, for the lased groups. CONCLUSIONS: LILT seemed to attenuate the radiation-related damage in alveolar bones.

Evaluation of socket healing in irradiated rats after diode laser exposure (histological and morphometric studies).

OBJECTIVE: The purpose of this study is to evaluate the effect of low-level laser therapy (LLLT) in enhancing bone repair in irradiated sockets of albino rats. DESIGN: Thirty male Swiss Albino rats ranging from 120 to 150 g were used in this study. The animals were subjected 6 gray gamma radiations. Three days post irradiation, right and left mandibular first molars were extracted. The sockets of the left sides were irradiated by (GaAIAs) diode laser device immediately after extraction, while the sockets of the right side were not exposed to the laser and served as control. The rats were randomly assigned into three groups (10 rats each) according to the date of sacrifice, 3, 7 and 10 days into groups I, II and III, respectively. The two sides of each mandible were separated. Each group was further subdivided into subgroups A and B (10 specimens each), where A represents the right side of the mandible and B represents the left side. The specimens were stained with hematoxylin and eosin, and Masson's trichrome. RESULTS: LLLT accelerated bone healing, while, radiotherapy induced delay of bone healing along the three experimental groups. This acceleration was assessed histologically by the presence of mature collagen fibre bundles and early new bone formation in the lased groups. Histomorphometric analysis revealed an increase in the area percentage of bone trabeculae in the lased sockets compared to the control ones in group II. This increase was statistically significant (p = 0.0274). The increase in the area percentage of bone trabeculae between the lased and control sockets of group III was statistically insignificant (p = 0.1903). CONCLUSIONS: In a rat model application of LLLT with a GaAIAs diode laser device can enhance bone healing and mineralisation in sockets subjected to gamma radiation.