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. 2022 Jan;29(1):324-330.
doi: 10.1016/j.sjbs.2021.08.095. Epub 2021 Sep 6.

Effect of kolaviron on islet dynamics in diabetic rats

Omolola R Oyenihi  1 , Marlon E Cerf  2   3 , Motlalepula G Matsabisa  4 , Nicole L Brooks  5 , Oluwafemi O Oguntibeju  1
Affiliations

Effect of kolaviron on islet dynamics in diabetic rats

Omolola R Oyenihi et al. Saudi J Biol Sci. 2022 Jan.

Abstract

Kolaviron, a biflavonoid isolated from the edible seeds of Garcinia kola, lowers blood glucose in experimental models of diabetes; however, the underlying mechanisms are not yet fully elucidated. The objective of the current study was to assess the effects of kolaviron on islet dynamics in streptozotocin-induced diabetic rats. Using double immunolabeling of glucagon and insulin, we identified insulin-producing β- and glucagon-producing α-cells in the islets of diabetic and control rats and determined the fractional β-cell area, α-cell area and islet number. STZ challenged rats presented with islet hypoplasia and reduced β-cell area concomitant with an increase in α-cell area. Kolaviron restored some islet architecture in diabetic rats through the increased β-cell area. Overall, kolaviron-treated diabetic rats presented a significant (p < 0.05) increase in the number of large and very large islets compared to diabetic control but no difference in islet number and α-cell area. The β-cell replenishment potential of kolaviron and its overall positive effects on glycemic control suggest that it may be a viable target for diabetes treatment.

Keywords: Diabetes; Garcinia kola; Islets; Kolaviron; α-cell; β-cell.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Fig. 1
Fig. 1
Chemical structure of the bioactive compounds in Kolaviron – a Garcinia biflavonoid complex.
Fig. 2
Fig. 2
The effect of kolaviron on glucose level in diabetic and non-diabetic rats over a 6-week treatment period. Data are presented as means ± S.D. Confirmation of diabetes (COD); Non-diabetic control (C), control treated with kolaviron (C + KV), untreated diabetic rats (D), diabetic rats treated with kolaviron (D + KV). * p < 0.05 compared to non-diabetic control rats, # p < 0.05 compared to diabetic control rats.
Fig. 3
Fig. 3
Pancreata immunostained for glucagon-positive α-cells (brown staining) and insulin-positive β-cells (pink staining). Non-diabetic control (C), control treated with kolaviron (C + KV), untreated diabetic rats (D), diabetic rats treated with kolaviron (D + KV). Magnification X20.
Fig. 4
Fig. 4
Total islet number, β-cell and α- cell area. Data are presented as means ± S.D. * p < 0.05 compared to non-diabetic control rats, #p < 0.05 compared to diabetic control rats. Non-diabetic control (C), control treated with kolaviron (C + KV), untreated diabetic rats (D), diabetic rats treated with kolaviron (D + KV).
Fig. 5
Fig. 5
Size distribution of islets in rats. Size distribution of small-medium islets (0–12,500 µm) and large-very large islets (12,501 – >20,000 µm) in normal and diabetic rats. Data are presented as means ± S.D. * p < 0.05 compared to non-diabetic control rats, # p < 0.05 compared to diabetic control rats. Non-diabetic control rats (Black), non-diabetic control rats treated with kolaviron (Grey), untreated diabetic rats (Deep blue), diabetic rats treated with kolaviron (Light blue).
See this image and copyright information in PMC

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