Task: Question Answering
Input (English): Context: To determine whether sympathetic nerves regulate expression of known angiogenic growth factors.', 'Surgical sympathectomy (SNX) was used to remove sympathetic innervation to the eye. Real-time PCR was used to measure steady state mRNA expression of VEGF, VEGFR-2, angiopoietin-1, and Tie2. Western blot analysis was performed to assess protein expression. Blood-retinal barrier (BRB) permeability surface area product (PS) was measured using enhanced MRI on a separate group of control and SNX rats.', 'mRNA of both VEGF and VEGFR-2 decreased significantly at 6 weeks after SNX. VEGF protein expression also decreased significantly. VEGFR-2 protein was unchanged. Both angiopoietin-1 and Tie2 mRNA expression increased significantly after SNX. Immunoblot analysis showed that angiopoietin-1 protein expression coincided with its mRNA expression. Tie2 protein expression was unaffected. Sympathetic denervation did not significantly increase BRB PS.\Question: Does superior cervical ganglionectomy induce changes in growth factor expression in the rat retina?
Output (English): Surgical SNX results in a reduction in VEGF gene and protein expression, while increasing protein expression of Ang-1. These findings suggest that sympathetic nerves regulate the expression of angiogenic growth factors in rat retina.