Distinct Patterns of Renal Autoregulatory Impairment in Rat Models Susceptible to Hypertensive-Renal Injury
Abstract
Background: Renal autoregulation protects glomeruli from hypertensive injury. Impaired autoregulation has previously been detected under anesthesia in models such as Sprague–Dawley (SD) rats with 3/4 renal mass reduction (RKNX) and Dahl salt-sensitive (SS) rats, both of which are susceptible. In contrast, Spontaneously Hypertensive (SHR) and stroke-prone SHR (SHRsp) rats exhibit intact autoregulation and are protected (PMID: 23132368). Here, we examined the dynamics of renal autoregulation in conscious, chronically instrumented SD, RKNX, Dahl SS, SHR, and SHRsp rats. Methods: We analyzed historical blood pressure (BP) and renal blood flow (RBF) data from SD (n=10), RKNX (n=17), SHR (n=17), and SHRsp (n=20) rats and collected new data from Dahl SS (n=14) rats. All rats (male, 10-13-week-old) were instrumented with a transit-time RBF probe and BP radiotelemeter. After one week of recovery, BP and RBF were sampled (500 Hz) over 1-4 days in the conscious state. Short-segment autoregulatory indices (PMID: 31792155) quantified the kinetics (2.5sec) and magnitude (20sec) of responses to spontaneous BP fluctuations ≥±5 mmHg. Group and segment effects were analyzed by 2-way repeated measures ANOVA with Tukey’s post hoc test. Data are mean±SE, and P<0.05 was considered statistically significant. Results: SHR and SHRsp showed rapid, complete autoregulatory responses by 2.5sec, which were faster (P<0.05) than SD (Fig. 1a). Dahl SS responses were similar to SD at 2.5sec and faster (P<0.05) than RKNX (Fig. 1b). However, while SD and RKNX achieved complete autoregulation by 20sec, Dahl SS failed to reach full magnitude, with no significant difference between 2.5- and 20-sec segments. Conclusions: Distinct autoregulatory defects were observed in susceptible models: RKNX with slowed kinetics and Dahl SS with incomplete magnitude. In contrast, resistant SHR and SHRsp exhibited rapid, complete responses. These findings indicate that different patterns of impaired autoregulation are associated with enhanced susceptibility to hypertensive renal injury.
Start Time
15-4-2026 11:00 AM
End Time
15-4-2026 12:00 PM
Room Number
303
Presentation Type
Oral Presentation
Presentation Subtype
Grad/Comp Orals
Presentation Category
Health
Student Type
Graduate
Faculty Mentor
Aaron Polichnowski
Distinct Patterns of Renal Autoregulatory Impairment in Rat Models Susceptible to Hypertensive-Renal Injury
303
Background: Renal autoregulation protects glomeruli from hypertensive injury. Impaired autoregulation has previously been detected under anesthesia in models such as Sprague–Dawley (SD) rats with 3/4 renal mass reduction (RKNX) and Dahl salt-sensitive (SS) rats, both of which are susceptible. In contrast, Spontaneously Hypertensive (SHR) and stroke-prone SHR (SHRsp) rats exhibit intact autoregulation and are protected (PMID: 23132368). Here, we examined the dynamics of renal autoregulation in conscious, chronically instrumented SD, RKNX, Dahl SS, SHR, and SHRsp rats. Methods: We analyzed historical blood pressure (BP) and renal blood flow (RBF) data from SD (n=10), RKNX (n=17), SHR (n=17), and SHRsp (n=20) rats and collected new data from Dahl SS (n=14) rats. All rats (male, 10-13-week-old) were instrumented with a transit-time RBF probe and BP radiotelemeter. After one week of recovery, BP and RBF were sampled (500 Hz) over 1-4 days in the conscious state. Short-segment autoregulatory indices (PMID: 31792155) quantified the kinetics (2.5sec) and magnitude (20sec) of responses to spontaneous BP fluctuations ≥±5 mmHg. Group and segment effects were analyzed by 2-way repeated measures ANOVA with Tukey’s post hoc test. Data are mean±SE, and P<0.05 was considered statistically significant. Results: SHR and SHRsp showed rapid, complete autoregulatory responses by 2.5sec, which were faster (P<0.05) than SD (Fig. 1a). Dahl SS responses were similar to SD at 2.5sec and faster (P<0.05) than RKNX (Fig. 1b). However, while SD and RKNX achieved complete autoregulation by 20sec, Dahl SS failed to reach full magnitude, with no significant difference between 2.5- and 20-sec segments. Conclusions: Distinct autoregulatory defects were observed in susceptible models: RKNX with slowed kinetics and Dahl SS with incomplete magnitude. In contrast, resistant SHR and SHRsp exhibited rapid, complete responses. These findings indicate that different patterns of impaired autoregulation are associated with enhanced susceptibility to hypertensive renal injury.
