Abstract Body: Hypertension is known to be associated with water-electrolyte balance disturbances that lead to changes in osmotic pressure. Osmolytes are small organic molecules essential for cellular adaptation to changes in osmotic pressure.
This study investigates the levels of osmolytes in serum and tissues using two well-established rat models of hypertension: spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats with angiotensin II-induced hypertension (WKY-ANG).
Experiments were conducted on male Wistar-Kyoto (WKY) rats, SHRs, and WKY-ANG rats. Blood and tissue samples were collected from all groups for liquid chromatography with mass spectrometry (LC-MS) analysis of selected osmolytes.
Anesthetized SHR and WKY-ANG rats displayed significantly elevated mean arterial blood pressures compared to WKY rats (118.4±1.3, 110.2±0.9, and 76.5±1.2 mmHg, respectively). The serum and tissue levels of sarcosine were significantly decreased in SHRs compared to WKY rats (1.90±0.21 vs. 3.80±0.80 for serum, 55.55±9.79 vs 92.37±10.57 for liver, 6.06±0.78 vs. 10.55±1.19 for renal cortex, 9.14±0.45 vs.13.83±1.14 for renal medulla, 11.59±1.17 vs. 22.34±3.11 for lungs, 1.80±0.14 vs. 3.30±0.39 for heart, respectively). Reduced levels of beta-alanine were observed only in the serum of SHRs compared to WKY and WKY-ANG rats (6.48±0.93 vs. 59.43±9.47, 41.32±3.13 respectively). Additionally, higher levels of L-alanine were noted in the renal cortex and medulla of WKY than in SHRs and WKY-ANG rats (19685±592.3 vs. 14510±456.8, 14289±719.4 for cortex and 14043±560.3 vs. 11520±206.8, 10651±292.4 for medulla, respectively). Conversely, SHR rats exhibited significantly higher levels of serum glycerophosphocholine (GPC) than WKY-ANG rats (38.21±10.02 vs. 12.47±2.25). Simultaneously, lower levels of betaine were observed in the lungs of SHR rats when compared to WKY and WKY-ANG rats (1 and 351.20±36.02, 607.10±64.20, 606.70±55.88 for lungs respectively). All results are indicated in μmol/L and means±SE.
In conclusion significant alterations in osmolyte concentrations are evident in hypertensive rats. These findings suggest that hypertension may be associated with disruptions in osmolyte balance. Further studies are needed to assess the potential clinical significance of osmolyte disturbances in hypertension.