Alpha-chymotrypcin ameliorates neuroinflammation and apoptosis characterizing Alzheimer's disease-induced in ovarictomized rats.

Objective: Alzheimer's disease (AD) is the most common cause of dementia in the elderly. Very little is known about the causes of AD, except that its end stages involve extensive neuronal loss and the appearance of distinctive neuropathological features. This study was under taken to investigate the role of α-chymotrypcin (α-ch) in management of AD-induced in ovariectomized rats.
Design: Sixty female Sprague Dawley rats were divided into four groups n=15, (1) normal control group (con), (2) group underwent surgery to remove ovaries (ovx control group), (3) ovx group received aluminum chloride in a dose of 17 mg/kg daily for 2 months to induce AD (AD group), (4) AD group treated with α-chymotrypcin (α-ch) at dose (8.1 unit/rat/day) which is equivalent to the recommended human dose (α-ch-treated group) for three months. At the end of the experimental period, rats were sacrificed; brain samples were obtained for different biochemical analyses and histopathological examination. The biochemical analyses included determination of tumor necrosis factor-α (TNF- α), IL-18, monocyte chemo attractant protein-1 MCP-1, FAS, B-cell lymphoma 2 (Bcl2).
Results: In comparison with normal control group, the ovx control group recorded significant increase in the brain levels of TNF-α, IL-18, MCP-1 and FAS. On the other hand, the brain level of Bcl2 was significantly decreased. Also, AD group showed a significant increase in TNF-α, IL-18, MCP-1 and FAS levels in brain tissue. In contrast, significant decrease in brain Bcl2 level was detected in AD group as compared to the ovx control group. However, the treatment of AD group with α-chymotrypcin caused an improvement in the most studied biochemical parameters as indicated by decreased brain levels of TNF-α, IL-18, MCP-1 and FAS accompanied with significant increase in the level of Bcl2 compared to AD group. Histopathological investigation of brain tissue of ovx rats administered with aluminum (AD group) showed AD plaques. While, AD group treated with α-chymotrypcin showed great improvement in the brain morphological structure with the disappearance of amyloid plaques.
Conclusion: This study revealed that α-chymotrypcin significantly ameliorates the neuroinflammation characterizing Alzheimer's disease in ovariectomized rats due to it's proteolytic activity as well as it's anti-inflammatory effect.
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