Change in the bladder function of rats with focal cerebral infarction induced by photochemically-induced thrombosis

The photochemically-induced thrombosis(photothrombosis) method can create focal cerebral infarcts anywhere in the relatively superficial layers of the cerebrum; it is easy to implement and minimally invasive. Taking advantage of this versatility, we aimed to establish a new rat model of urinary frequency with focal cerebral infarction, which was characterized by its simplicity, nonlethal nature, and high reproducibility. The prefrontal cortex and the anterior cingulate cortex, which are urinary centers, were targeted for focal cerebral infarction, and urinary parameters were measured by cystometrogram. Cystometric analysis indicated that micturition intervals significantly shortened in photothrombosis-treated rats compared with those in the sham operative group on Days 1 and 7 (P < 0.01), but prolonged after 14 days, with no difference between the two groups. Immunopathological evaluation showed an accumulation of activated microglia, followed by an increase in reactive astrocytes at the peri-infarct zone after photothrombotic stroke. Throughout this study, all postphotothrombosis rats showed cerebral infarction in the prefrontal cortex and anterior cingulate cortex; there were no cases of rats with fatal cerebral infarction. This model corresponded to the clinical presentation, in that the micturition status changed after stroke. In conclusion, this novel model combining nonlethality and high reproducibility may be a suitable model of urinary frequency after focal cerebral infarction.


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Evaluation of infarction area and volume

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As shown in Fig. 2, the sagittal brain sections on Day 1 after photothrombosis 209 revealed infarcted PFC and ACC lesions. All the rats in this study had similar areas of 210 infarction (Fig. S2). No damage was observed in the brain stem, such as PAG or PMC 211 regions, in either group. The mean infarction volume was 147.1 ± 24.1 mm 3 . No evidence 212 of infarction was found in any of the sham rats.

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The body and bladder weights are shown in Table 1 Figure 3 show the results of neurobehavioral assessments with the mNSS test for 222 each rat. All of the individual data points are detailed in the Supporting Information (File 223 S1). Immediately after photothrombosis, the rats showed characteristic motor changes, 224 with bilateral hind limbs flexed when suspended by the tail. Furthermore, rats with 225 cerebral infarction from photothrombosis were observed to have balance disorders in the 226 beam balance test (walking on a 3-cm beam); however, there were no sensory or reflex 227 disturbances. There were no abnormal neurological findings in the sham group at all.
228 Therefore, the mNSS was significantly higher in the PT group than in the sham group at

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In this study, we used a photothrombotic stroke method to induce focal infarcts in 252 PFC and ACC, and we observed decreased ICIs on Days 1 and 7, according to the 253 cystometric analysis. Furthermore, all rats survived after the operation. To the best of our 254 knowledge, this is the first study in which photothrombosis has been applied to measure 255 urinary function.

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The method of inducing a stroke in the cerebral cortex using photochemical 267 or other limbic system, which is necessary to sustain vital functions.

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There was no difference in bladder weight or bladder to body weight ratio between 269 the sham and PT groups, which is the same result as obtained in the MCAO model [16].
270 This suggests that urinary frequency is due to dysfunction of the central nervous system.

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Once necrotic, mature neurons do not recover, but the urinary status of the rats 284 changed after stroke in this study. It is possible that the surrounding tissue near the 285 necrotic lesion, which is called the penumbra, compensated for the loss function.
286 Microglia, the immune cells resident in the brain, are the first to respond to ischemic 287 neurons and promote their survival [29]. Following this, it has been suggested that 288 reactive astrocytes in the penumbra contribute to brain remodeling, such as neuronal 289 circuitry and tissue reorganization [30]. Activations of these glial cells within the peri-290 infarct territory after focal cerebral infarction were reported to occur rapidly within a few

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The authors acknowledge the assistance of Naomi Kasuga in the experiments. This  File S1. All individual data points in modified neurological severity score

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The spreadsheet contains the raw data points used to create the graph.