Effect of puerarin on glutamine synthetase activity in rat retina following acute intraocular hypertension

This study was conducted to demonstrate whether puerarin regulates glutamine synthetase (GS) activity following intraocular hypertension and has therapeutic potential in ophthalmology for the protection of optic nerves in patients with glaucoma. This study used a Wistar rat model of acute closed-angle glaucoma to investigate the effect of puerarin on GS activity in rat retina following intraocular hypertension. Acute intraocular hypertension was induced by increasing anterior chamber pressure to 110 mmHg for 30 min in the left eyes of 50 Wistar rats, while 5 additional Wistar rats lacking intraocular hypertension were used as a control group. Retinal GS activity was measured at 4, 12, 24, 36 and 72 h after induction of acute intraocular hypertension with/without puerarin treatment. Compared to the control group that lacked intraocular hypertension, GS activity in the intraocular hypertension group significantly decreased at 4 and 12 h (P<0.01), before increasing at 24 to 36 h and restoring to a level similar to the control group at 72 h. However, puerarin significantly (P<0.05) prevented the loss of GS activity seen in the intraocular hypertension group at 4 and 12 h, with no significant (P<0.05) difference in GS activity noted between the control group and rats treated with puerarin at these early time points. GS activity significantly (P<0.05) increased above control values at 24 and 36 h in the puerarin-treated group before eventually restoring to control levels at 72 h. These findings suggest puerarin protects GS activity in the early stages of retinal acute intraocular hypertension and may be of potential therapeutic benefit in acute closed-angle glaucoma. Key words: Puerarin, acute intraocular hypertension, glutathione synthetase.