Effects Of Low-dose Radiation On Hippocampal Damage Of Male Diabetic Rats And Its Mechanisms

Diabetic encephalopathy is one of late complications of diabetes mellitus,which is induced by glucose metabolic disorder and change in vessel,associated with moderate cognitive deficits and neurophysiological and structural changes in the brain, and characterised by acquired cognitive and behavioural deficits. The clinical characteristics of diabetic encephalopathy are deficits in learning, memory and cognitive behavior.1. Effects of LDR on body weight and blood glucose in diabetic ratsBoth body weight and blood glucose in diabetic rats were measured at pre- and post-exprement. There was not significant difference in body weight of different groups at pre-exprement. Three months later, the body weight in diabetic rats treated by LDR was lightly higher than that in diabetic rats, but greatly lower than that in normal control rats. Moreover, there was not significant difference in blood glucose of different groups at pre-exprement. The value of blood glucose in different groups was higher than that in normal control and that in diabetic rats was significant higher than that in diabetic rats treated with 75 mGy(P < 0.05)was highest.2. LDR reduces the apoptosis of diabetic rats'hippocampal neurons FCM was applied to detect the change of apoptosis in different groups'hippocampal neurons. The results showed that the rate of apoptosis of diabetic rats'hippocampal neurons was higher than that in normal control rats. As compared with that in diabetic rats, the rates of other groups all were lower significantly in the diabetic rats treated with NAC and 25 mGy (P < 0.05).3. Effects of LDR on the distribution of cell cycle in hippocampal neuronsPI stain and FCM were applied to analyze the distribution of cell cycle in hippocampal neurons of diabetic rats induced by STZ. As compared with that in diabetic rats, the percentages in G0/G1 phase in other groups were lightly higher and significantly in the NAC group; the percentages in S phase in other groups were significantly reduced (P < 0.05); not significantly change in G2/M phase. These results indicated that there was obvious S phase delay in diabetic group, and STZ-induced diabetic rats treated with LDR have similar effects with that treated with NAC to lessen diabetic rats'S phase delay and revive the distribution of cell cycle.4 Effects of LDR on oxidative stress induced by diabete LDR can depress the production of oxygen free radical and elevate the competence of anti oxidative damage.4.1 LDR can reduce the generation of ROS LDR can reduce the generation of MDA in diabetic rats, which indicated that both the generation of ROS in diabetic rats and the level of lipid peroxidation were reduced.4.2 Effects of LDR on the anti-oxygen competence of the bodyThe results showed that the activities of SOD and CAT in diabetic rats treated with LDR were lower than those in diabetic rats. This indicated that the diabetic rats treated with LDR have lower competence in anti-oxygen which was paradox with the former results and needed .to investigate its definite mechanisms.5. Effects of LDR on the hippocampal synaptic plasticityLDR can restrain the release of Glu and block the open of Ca2+-channel, reduced the Ca2+ accumulation in hippocampal neurons,which restrain the activity of NMDA receptor, reduce the content and activity of iNOS, then reduce the generation of NO, maintain the hippocampal synaptic plasticity to protect the cognitive deficits.6. Effects of LDR on apoptosis related proteinFCM was applied to detect the changes of the expressions of Bax and Bcl-2 in diabetic rats'hippocampal neurons. The results showed that LDR can restrain the expressions of Bax and Bcl-2, greater in Bax. So the ratio of Bax and Bcl-2 reduced,which show the effect of anti-apoptosis.The expression of caspase 9 in rats'hippocampus was detected by Western blot. The results showed that the expression of caspase 9 in diabetic rats'hippocampal neurons treated with LDR relatively reduced, as compared with that in diabetic rats, which indicate that the apoptosis level of hippocampal neurons in diabetic rats treated with LDR was lower than that of sham-irradiated diabetic rats.Results of the project will provide the possible evidence for the further reseach on LDR effects in diabete therapy.