Figure 2.

Histological changes in the hippocampal CA3 region on the injured side of traumatic brain injury rats after hyperbaric oxygen therapy for 2 weeks (Nissl staining, optical microscopy, scale bars: A, × 25; B–D, × 200).

White arrows indicate Nissl-positive cells, black arrows indicate Nissl bodies. The black squares in B, C and D are the areas enlarged in the insert at the right upper of each image.

(A) Black square in A and B is the observed area.

(B) In the sham surgery group, hippocampal CA3 neurons were arranged tightly and the structure was intact.

(C) In the traumatic brain injury group, hippocampal CA3 neurons were arranged sparsely and disordered. A large number of pyknotic and necrotic neurons exhibited atrophy, and Nissl bodies decreased or disappeared.

(D) In the hyperbaric oxygen therapy group, the number of hippocampal CA3 neurons was increased significantly, and more compact compared with those in the traumatic brain injury group. The number of Nissl bodies was also increased.