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Effects of rotundine injection on nitric oxide synthase in tissue of different organs after ischemia/reperfusion of brain in rats
Abstract
To explore the protective effect of rotundine injection on lung, liver and kidney damages after cerebral ischemia/reperfusion (I/R) injury in rats based on the activity changes of nitric oxide synthase (NOS).
Seventy-six rats were randomly divided into three groups: sham operation group, I/R injury group and treatment group, and determinations were done at five different time points. The cerebral I/R models were reproduced by improved 4 vessels occlusion method. The activities of NOS in the lung, liver and kidney were measured in all the rats at 2, 6, 12, 24 and 48 hours after reperfusion.
Compared with sham operation group, the activities of total NOS (tNOS) were significantly increased at 2, 12 and 24 hours in I/R injury group (P<0.05 or P<0.01), with the peak value at 12 hours (all P<0.01). The activities of constitutive NOS (cNOS) were increased significantly at 2 hours (all P<0.05), and those of induced NOS (iNOS) were increased at 12 hours (all P<0.01). The activities of iNOS were still high at 24 hours (all P<0.05), and approached the levels of sham operation group at 48 hours. Compared with I/R injury group, the activities of cNOS in various organs increased much higher at 2 hours in treatment group (all P<0.05). But those of iNOS were significantly decreased after 12 hours (P<0.05 or P<0.01).
The various types of NOS play different roles in the lung damages after brain I/R injury at different stages in rats. Rotundine injection can ameliorate the damages by modulating the activities of different types of NOS.
... Several compounds inhibited neutrophil infiltration, TNF-α, and NO biosynthesis in response to ischaemia. After ischaemia/reperfusion in rat brains, rotundine decreased damage by acting on different types of nitric oxide synthase (NOS) (Zeng et al., 2007a). Similarly, l-stepholidine protected the striatal neurons against ischaemic injury in Sprague Dawley rats (Tang et al., 1999). ...
The goal of this study was to investigate the effect of endothelial cell proliferation on the expression and activity of endothelial nitric oxide synthase (eNOS). Bovine atrial endothelial cells (BAtEC) were studied between day 1 and 6 after seeding. During this period the number of cells in S-phase decreased progressively, while cell number and protein content increased, reaching a maximum at confluence (day 4). Expression of eNOS (determined by ELISA) and eNOS activity (determined by L-arginine to L-citrulline conversion) increased with culture duration with a maximum at confluence. Nitric oxide (*NO) release from BAtEC was determined after stimulation with Ca2+ ionophore A23187 (10 microM, 30 min) by .NO chemiluminescence in the absence of a chemical reduction system. Total *NO release (measured in the presence of 100 U/ml superoxide dismutase) did not change with state of cell proliferation/growth, whereas "bioavailable" *NO (measured in the absence of superoxide dismutase) was low in highly proliferating BAtEC. Relative eNOS activity (.NO and L-citrulline production per eNOS protein) was highest in proliferating BAtEC. The novel finding of this study is that the specific eNOS activity is upregulated in proliferating BAtEC and downregulated in quiescent BAtEC. The amount of "bioavailable" *NO is determined by eNOS activity and *NO inactivation (probably by superoxide), both high in proliferating BAtEC.