Objective-Endothelial dysfunction and vascular dysregulation contribute to the pathological effects of radiation on tissues. The objectives of this study were to assess the acute effect of irradiation on acetylcholine (Ach)-induced dilation of gut submucosal microvessels. Methods and Results-Rats were exposed in vivo to 1 to 9 cGy in 3 fractions per week on alternate days for 3 successive weeks for a total dose of up to 2250 cGy. Submucosal microvessels were isolated after varying levels of irradiation. Diameters of isolated vessels were measured using videomicroscopy, and the dose-response relationship to Ach was determined. Dihydroethidine and 2Ј, 7Ј-dichlorodihydrofluorescein diacetate fluorescent probes were used to assess reactive oxygen species (ROS) production. After constriction (30% to 50%) with endothelin, dilation to graded doses of Ach (10 Ϫ9 Ϫ10 Ϫ4 M) was observed in control vessels (maximal dilation [MD] 87Ϯ3%; nϭ7). However, Ach-induced dilation was reduced in vessels from irradiated rats (MDϭ3Ϯ9%; nϭ7; PϭϽ0.05 versus controls). Significant increases in superoxide and peroxides were observed in irradiated microvessels. Irradiated microvessels pretreated with superoxide dismutase-mimetic demonstrated significant improvement in Ach-induced vasodilation compared with irradiation alone, suggesting that superoxide contributes to impaired dilation to Ach after irradiation. Conclusions-Radiation

Recent evidence suggests that enhanced cell apoptosis is responsible for germ cell loss following testicular ischemia-reperfusion (IR) injury. A nonsteroidal anti-inflammatory drug diclofenac sodium (Voltaren) is a prostaglandin-synthesis inhibitor, which is widely used in many testicular disorders. The purpose of the present study was to examine the effect of diclofenac (DIC) on germ cell apoptosis in the ischemic and contralateral testes following testicular IR in a rat. Forty rats were divided randomly into four experimental groups of ten rats each: group A (Sham)-Sham operated animals; group B (Sham-DIC)-Sham operated rats that were treated with DIC given subcutaneously at a dose of 10 mg/kg, once daily, 24, 48 and 72 h following operation; group C (IR) underwent 90 min of unilateral testicular IR; group D (IR-DIC)-rats underwent 90 min of unilateral testicular IR and were treated with DIC similarly to group B. Ninety-six hours following operation, the rats were sacrificed and testes were harvested. Johnsen's criteria and the number of germinal cell layers were used to categorize the spermatogenesis. TUNEL assay was used to determine germ cell apoptosis in both the ischemic and contralateral testes. Statistical analysis was performed using the non-parametric Kruskal-Wallis ANOVA test, with P less than 0.05 considered statistically significant. Testicular ischemia in rats led to histological damage in the ipsilateral testis. In the contralateral testis, minimal damage was observed. Germ cell apoptosis in both the ischemic and the contralateral testes increased significantly after IR. Treatment with DIC did not change histologic parameters of spermatogenesis in both the ischemic and contralateral testes, but decreased germ cell apoptosis in both testes following testicular IR. We conclude that testicular ischemia causes an increase in germ cell apoptosis in the contralateral testis. Diclofenac may be beneficial for spermatogenesis following testicular IR by decreasing germ cell apoptosis.

SummaryRecent evidence suggests that lipopolysaccharide (LPS) endotoxaemia in a rat causes significant mucosal injury. Our objective was to determine the effects of glutamine (Gln) on Toll-like receptor 4 (TLR-4), myeloid differentiation factor 88 (Myd88) and tumour necrosis factor (TNF)-a receptor-associated factor 6 (TRAF6) expression in intestinal mucosa following LPS endotoxaemia in a rat. For this purpose, male Sprague-Dawley rats were assigned randomly to one of three experimental groups of 10 rats each: (i) control rats underwent intraperitoneal (i.p.) injection of sterile saline once a day; (ii) rats were treated with LPS given i.p. once a day at a dose of 10 mg/kg for 48 h (two doses); and (iii) rats were pretreated with oral Gln given in drinking water (2%) 48 h before and following injection of LPS. Intestinal mucosal parameters, enterocyte proliferation and apoptosis were determined at death. TLR-4 and MyD88 mRNA expression was measured with reverse transcriptionpolymerase chain reaction (RT-PCR). TLR-4 and MyD88 protein expression were analysed by Western immunoblotting. We observed a statistically significant (P < 0·05) decrease in mucosal weight, mucosal DNA and enterocyte proliferation and a significant increase in enterocyte apoptosis in rat intestine, following LPS administration. These changes were attenuated significantly by dietary Gln. Expression of TLR-4, MyD88 and TRAF6 mRNA in the mucosal ileum was significantly higher in LPS rats versus control rats (P = 0·0006, P = 0·0015, P = 0·03, respectively) as well as TLR-4 and MyD88 protein expression. The administration of Gln reduced significantly the expression of TLR-4, MyD88 and TRAF6 (P = 0·023, P = 0·014, P = 0·035, respectively) mRNA as well as TLR-4 and MyD88 protein expression in ileum compared to LPS animals. We did not find a significant change in the expression of TLR-4, MyD88 or TRAF6 in the jejunum of different groups. We conclude that treatment with Gln was associated with down-regulation of TLR-4, MyD88 and TRAF6 expression and concomitant decrease in intestinal mucosal injury caused by LPS endotoxaemia in a rat.