Effect of taurine on respiratory chain enzyme activities in mitochondria from rats with severe traumatic brain injury

Abstract

Objective To investigate effect of taurine on respiration chain enzyme activity of mitochondria 24 hours after severe traumatic brain injury (TBI) in rats. Methods Fifty-six SD rats weredivided into sham group, TBI group, taurine treatment group, and taurine prevention group according to the random number table, with 14 rats per group. Fluid percussion brain injury models were used. Via the caudal vein, normal saline was administered to animals in sham and traumatic brain injury groups immediately after injury, while taurine(200 mg/kg)was administered to animals in taurine treatment group after injury and in taurine prevention group 4 days before injury. Brains were harvested 24 hours postinjury for assays of HE staining and electron microscopy. Mitochondrial respiratory chain complex Ⅰ-Ⅴ activities were detected. Results TBI group presented swelling neurocytes, cell loss, karyopyknosis, shortened even vanished process, and inflammation cell infiltration at the edge of necrosis in HE staining. By contrast, morphological improvement was significant in taurine treatment group but only some neurons were intact in taurine prevention group. Swelling mitochondria and broken or vanished mitochondrial crests were seen in TBI group under the electron microscope. However, normal or minor swelling mitochondria was seen in taurine treatment group and cytoplasm slightly porous and absence of mitochondrial crests were seen in taurine prevention group. Activities of complex Ⅰ, Ⅱ and Ⅴ were significant lower in TBI group (32.52±2.41, 4.68±0.15, 2.49±0.73) compared to those in sham group (34.03±0.46, 5.04±0.29, 3.20±0.68) and in taurine treatment group (33.95±0.85, 5.12±0.23, 3.53±0.48) (P<0.05). And complex Ⅰ in taurine prevention group was significantly enhanced as well (34.44±0.36, P<0.05). Conclusion Taurine may protect the brain tissues and mitochondrial structure from impairment in TBI rats by improving mitochondrial enzymes activity and reducing secondary energy loss. Key words: Craniocerebral trauma; Taurine; Mitochondria; Enzyme activity